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Boyle MJ, Engwerda CR, Jagannathan P. The impact of Plasmodium-driven immunoregulatory networks on immunity to malaria. Nat Rev Immunol 2024; 24:637-653. [PMID: 38862638 DOI: 10.1038/s41577-024-01041-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 06/13/2024]
Abstract
Malaria, caused by infection with Plasmodium parasites, drives multiple regulatory responses across the immune landscape. These regulatory responses help to protect against inflammatory disease but may in some situations hamper the acquisition of adaptive immune responses that clear parasites. In addition, the regulatory responses that occur during Plasmodium infection may negatively affect malaria vaccine efficacy in the most at-risk populations. Here, we discuss the specific cellular mechanisms of immunoregulatory networks that develop during malaria, with a focus on knowledge gained from human studies and studies that involve the main malaria parasite to affect humans, Plasmodium falciparum. Leveraging this knowledge may lead to the development of new therapeutic approaches to increase protective immunity to malaria during infection or after vaccination.
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Affiliation(s)
- Michelle J Boyle
- Life Sciences Division, Burnet Institute, Melbourne, Victoria, Australia.
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | | | - Prasanna Jagannathan
- Department of Medicine, Stanford University, Stanford, CA, USA.
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA.
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Nikulkova M, Abdrabou W, Carlton JM, Idaghdour Y. Exploiting integrative metabolomics to study host-parasite interactions in Plasmodium infections. Trends Parasitol 2024; 40:313-323. [PMID: 38508901 PMCID: PMC10994734 DOI: 10.1016/j.pt.2024.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 03/22/2024]
Abstract
Despite years of research, malaria remains a significant global health burden, with poor diagnostic tests and increasing antimalarial drug resistance challenging diagnosis and treatment. While 'single-omics'-based approaches have been instrumental in gaining insight into the biology and pathogenicity of the Plasmodium parasite and its interaction with the human host, a more comprehensive understanding of malaria pathogenesis can be achieved through 'multi-omics' approaches. Integrative methods, which combine metabolomics, lipidomics, transcriptomics, and genomics datasets, offer a holistic systems biology approach to studying malaria. This review highlights recent advances, future directions, and challenges involved in using integrative metabolomics approaches to interrogate the interactions between Plasmodium and the human host, paving the way towards targeted antimalaria therapeutics and control intervention methods.
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Affiliation(s)
- Maria Nikulkova
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 11101, USA; Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Wael Abdrabou
- Program in Biology, Division of Science and Mathematics, New York University, Abu Dhabi, United Arab Emirates
| | - Jane M Carlton
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 11101, USA; Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | - Youssef Idaghdour
- Program in Biology, Division of Science and Mathematics, New York University, Abu Dhabi, United Arab Emirates
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Mandal RK, Schmidt NW. Mechanistic insights into the interaction between the host gut microbiome and malaria. PLoS Pathog 2023; 19:e1011665. [PMID: 37824458 PMCID: PMC10569623 DOI: 10.1371/journal.ppat.1011665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023] Open
Abstract
Malaria is a devastating infectious disease and significant global health burden caused by the bite of a Plasmodium-infected female Anopheles mosquito. Gut microbiota was recently discovered as a risk factor of severe malaria. This review entails the recent advances on the impact of gut microbiota composition on malaria severity and consequence of malaria infection on gut microbiota in mammalian hosts. Additionally, this review provides mechanistic insight into interactions that might occur between gut microbiota and host immunity which in turn can modulate malaria severity. Finally, approaches to modulate gut microbiota composition are discussed. We anticipate this review will facilitate novel hypotheses to move the malaria-gut microbiome field forward.
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Affiliation(s)
- Rabindra K. Mandal
- Ryan White Center for Pediatric Infectious Diseases and Global Health, Herman B Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indiana, United States of America
| | - Nathan W. Schmidt
- Ryan White Center for Pediatric Infectious Diseases and Global Health, Herman B Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indiana, United States of America
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Ahmad A, Mohammed NI, Joof F, Affara M, Jawara M, Abubakar I, Okebe J, Ceesay S, Hamid-Adiamoh M, Bradley J, Amambua-Ngwa A, Nwakanma D, D'Alessandro U. Asymptomatic Plasmodium falciparum carriage and clinical disease: a 5-year community-based longitudinal study in The Gambia. Malar J 2023; 22:82. [PMID: 36882754 PMCID: PMC9993664 DOI: 10.1186/s12936-023-04519-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/28/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Carriers of persistent asymptomatic Plasmodium falciparum infections constitute an infectious reservoir that maintains malaria transmission. Understanding the extent of carriage and characteristics of carriers specific to endemic areas could guide use of interventions to reduce infectious reservoir. METHODS In eastern Gambia, an all-age cohort from four villages was followed up from 2012 to 2016. Each year, cross-sectional surveys were conducted at the end of the malaria transmission season (January) and just before the start of the next one (June) to determine asymptomatic P. falciparum carriage. Passive case detection was conducted during each transmission season (August to January) to determine incidence of clinical malaria. Association between carriage at the end of the season and at start of the next one and the risk factors for this were assessed. Effect of carriage before start of the season on risk of clinical malaria during the season was also examined. RESULTS A total of 1403 individuals-1154 from a semi-urban village and 249 from three rural villages were enrolled; median age was 12 years (interquartile range [IQR] 6, 30) and 12 years (IQR 7, 27) respectively. In adjusted analysis, asymptomatic P. falciparum carriage at the end of a transmission season and carriage just before start of the next one were strongly associated (adjusted odds ratio [aOR] = 19.99; 95% CI 12.57-31.77, p < 0.001). The odds of persistent carriage (i.e. infected both in January and in June) were higher in rural villages (aOR = 13.0; 95% CI 6.33-26.88, p < 0.001) and in children aged 5-15 years (aOR = 5.03; 95% CI 2.47-10.23, p = < 0.001). In the rural villages, carriage before start of the season was associated with a lower risk of clinical malaria during the season (incidence risk ratio [IRR] 0.48, 95% CI 0.27-0.81, p = 0.007). CONCLUSIONS Asymptomatic P. falciparum carriage at the end of a transmission season strongly predicted carriage just before start of the next one. Interventions that clear persistent asymptomatic infections when targeted at the subpopulation with high risk of carriage may reduce the infectious reservoir responsible for launching seasonal transmission.
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Affiliation(s)
- Abdullahi Ahmad
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia.
- Global Health Institute, University of Antwerp, Gouverneur Kinsbergencentrum, Campus Drie Eiken, Doornstraat 331, 2610, Wilrijk, Belgium.
| | - Nuredin Ibrahim Mohammed
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Fatou Joof
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Muna Affara
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Musa Jawara
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Ismaela Abubakar
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Joseph Okebe
- International Public Health Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Serign Ceesay
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Majidah Hamid-Adiamoh
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Davis Nwakanma
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia.
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
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Susceptibility to malaria in fulani, Bariba, Otamari and gando individuals living in sympatry in Benin: Role of opsonizing antibodies to Plasmodium falciparum merozoites. Heliyon 2023; 9:e13092. [PMID: 36711279 PMCID: PMC9879790 DOI: 10.1016/j.heliyon.2023.e13092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/17/2022] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Objectives Fulani in Africa are known to be less susceptible to Plasmodium falciparum (Pf) malaria. This study explored a potential involvement of antibody-mediated merozoite phagocytosis mechanism in this natural protection against malaria. Methods Before the start of the malaria transmission season (MTS) in Benin, the functionality of antibodies against Pf merozoites was determined by the opsonic phagocytosis (OP) assay in plasma samples from Fulani, Bariba, Otamari and Gando groups. These individuals were actively followed-up for malaria detection from the beginning to the end of MTS. Anti-GLURP Immunoglobulin G antibody quantification, malaria Rapid Diagnostic Test (RDT) and spleen palpation were performed before and after MTS. Results In Bariba, Otamari and Gando, but not in Fulani, plasma from adults promoted higher levels of OP than the children (P = 0.003; P = 0.012; P = 0.031 and P = 0.122). A high proportion of Fulani children had higher OP and anti-GLURP (P < 0.0001) antibody levels as compared to non-Fulani children; whereas this was not observed for Fulani adults (P = 0.223). High OP levels before MTS were significantly related to negative RDT after MTS (P = 0.011). Conclusion Our results highlight the ability of opsonizing antibodies to potentially enhance natural protection of young Fulani individuals against Pf malaria in Benin.
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Henry B, Volle G, Akpovi H, Gineau L, Roussel C, Ndour PA, Tossou F, Suarez F, Palstra F, Fricot A, Chambrion C, Solinc J, Nguyen J, Garé M, Aussenac F, Cottart CH, Keyser C, Adamou R, Tichit M, Hardy D, Fievet N, Clain J, Garcia A, Courtin D, Hermine O, Sabbagh A, Buffet P. Splenic clearance of rigid erythrocytes as an inherited mechanism for splenomegaly and natural resistance to malaria. EBioMedicine 2022; 82:104167. [PMID: 35843175 PMCID: PMC9297103 DOI: 10.1016/j.ebiom.2022.104167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022] Open
Affiliation(s)
- Benoît Henry
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France; Service des maladies infectieuses et tropicales, APHP, Hôpital Necker Enfants Malades, Centre d'Infectiologie Necker-Pasteur, Institut Imagine, Paris, France; Service des maladies infectieuses et tropicales, APHP. Université Paris Saclay, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Geoffroy Volle
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France
| | - Hilaire Akpovi
- CERPAGE (Centre d'Etude et de Recherche sur les Pathologies Associées à la Grossesse et à l'Enfance), Cotonou, Bénin
| | - Laure Gineau
- Laboratoire d'Excellence Gr-Ex, Paris, France; Université Paris Cité, IRD, MERIT, Paris, France
| | - Camille Roussel
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France
| | - Papa Alioune Ndour
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France
| | - Félicien Tossou
- Centre Interfacultaire de Formation et de Recherche en Environnement pour le Développement Durable (CIFRED), Université d'Abomey-Calavi, Cotonou, Bénin; Ministère de la Santé, Cotonou, Bénin
| | - Felipe Suarez
- Laboratoire d'Excellence Gr-Ex, Paris, France; Service d'hématologie adultes, APHP, Hôpital Necker Enfants Malades, Paris, France; Université Paris Cité, INSERM U1163, CNRS ERL 8654, Paris, France
| | - Friso Palstra
- Laboratoire d'Excellence Gr-Ex, Paris, France; Université Paris Cité, IRD, MERIT, Paris, France
| | - Aurélie Fricot
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France
| | - Charlotte Chambrion
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France
| | - Julien Solinc
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France
| | - Julie Nguyen
- Laboratoire d'Excellence Gr-Ex, Paris, France; Université Paris Cité, IRD, MERIT, Paris, France
| | - Mathilde Garé
- CERPAGE (Centre d'Etude et de Recherche sur les Pathologies Associées à la Grossesse et à l'Enfance), Cotonou, Bénin; Université Paris Cité, IRD, MERIT, Paris, France
| | - Florentin Aussenac
- CERPAGE (Centre d'Etude et de Recherche sur les Pathologies Associées à la Grossesse et à l'Enfance), Cotonou, Bénin; Université Paris Cité, IRD, MERIT, Paris, France
| | - Charles-Henry Cottart
- Service de biochimie générale, APHP, Hôpital Necker Enfants Malades, Faculté de pharmacie, Paris, France
| | | | - Rafiou Adamou
- CERPAGE (Centre d'Etude et de Recherche sur les Pathologies Associées à la Grossesse et à l'Enfance), Cotonou, Bénin
| | - Magali Tichit
- Institut Pasteur, Experimental Neuropathology Unit, Paris, France
| | - David Hardy
- Institut Pasteur, Experimental Neuropathology Unit, Paris, France
| | - Nadine Fievet
- Laboratoire d'Excellence Gr-Ex, Paris, France; CERPAGE (Centre d'Etude et de Recherche sur les Pathologies Associées à la Grossesse et à l'Enfance), Cotonou, Bénin; Université Paris Cité, IRD, MERIT, Paris, France
| | - Jérôme Clain
- Laboratoire d'Excellence Gr-Ex, Paris, France; Université Paris Cité, IRD, MERIT, Paris, France
| | - André Garcia
- Laboratoire d'Excellence Gr-Ex, Paris, France; CERPAGE (Centre d'Etude et de Recherche sur les Pathologies Associées à la Grossesse et à l'Enfance), Cotonou, Bénin; Université Paris Cité, IRD, MERIT, Paris, France
| | - David Courtin
- Laboratoire d'Excellence Gr-Ex, Paris, France; CERPAGE (Centre d'Etude et de Recherche sur les Pathologies Associées à la Grossesse et à l'Enfance), Cotonou, Bénin; Université Paris Cité, IRD, MERIT, Paris, France
| | - Olivier Hermine
- Laboratoire d'Excellence Gr-Ex, Paris, France; Service d'hématologie adultes, APHP, Hôpital Necker Enfants Malades, Paris, France; Université Paris Cité, INSERM U1163, CNRS ERL 8654, Paris, France
| | - Audrey Sabbagh
- Laboratoire d'Excellence Gr-Ex, Paris, France; Université Paris Cité, IRD, MERIT, Paris, France
| | - Pierre Buffet
- Université Paris Cité, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France; Laboratoire d'Excellence Gr-Ex, Paris, France; Institut National de la Transfusion Sanguine, Paris, France; Institut Pasteur, Paris, France.
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Mapunda JA, Tibar H, Regragui W, Engelhardt B. How Does the Immune System Enter the Brain? Front Immunol 2022; 13:805657. [PMID: 35273596 PMCID: PMC8902072 DOI: 10.3389/fimmu.2022.805657] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 01/31/2022] [Indexed: 12/13/2022] Open
Abstract
Multiple Sclerosis (MS) is considered the most frequent inflammatory demyelinating disease of the central nervous system (CNS). It occurs with a variable prevalence across the world. A rich armamentarium of disease modifying therapies selectively targeting specific actions of the immune system is available for the treatment of MS. Understanding how and where immune cells are primed, how they access the CNS in MS and how immunomodulatory treatments affect neuroinflammation requires a proper knowledge on the mechanisms regulating immune cell trafficking and the special anatomy of the CNS. The brain barriers divide the CNS into different compartments that differ with respect to their accessibility to cells of the innate and adaptive immune system. In steady state, the blood-brain barrier (BBB) limits immune cell trafficking to activated T cells, which can reach the cerebrospinal fluid (CSF) filled compartments to ensure CNS immune surveillance. In MS immune cells breach a second barrier, the glia limitans to reach the CNS parenchyma. Here we will summarize the role of the endothelial, epithelial and glial brain barriers in regulating immune cell entry into the CNS and which immunomodulatory treatments for MS target the brain barriers. Finally, we will explore current knowledge on genetic and environmental factors that may influence immune cell entry into the CNS during neuroinflammation in Africa.
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Affiliation(s)
| | - Houyam Tibar
- Medical School of Rabat, Mohamed 5 University, Rabat, Morocco.,Hôpital des spécialités de Rabat, Ibn Sina University Hospital of Rabat, Rabat, Morocco
| | - Wafa Regragui
- Medical School of Rabat, Mohamed 5 University, Rabat, Morocco.,Hôpital des spécialités de Rabat, Ibn Sina University Hospital of Rabat, Rabat, Morocco
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Immunosuppression in Malaria: Do Plasmodium falciparum Parasites Hijack the Host? Pathogens 2021; 10:pathogens10101277. [PMID: 34684226 PMCID: PMC8536967 DOI: 10.3390/pathogens10101277] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/13/2022] Open
Abstract
Malaria reflects not only a state of immune activation, but also a state of general immune defect or immunosuppression, of complex etiology that can last longer than the actual episode. Inhabitants of malaria-endemic regions with lifelong exposure to the parasite show an exhausted or immune regulatory profile compared to non- or minimally exposed subjects. Several studies and experiments to identify and characterize the cause of this malaria-related immunosuppression have shown that malaria suppresses humoral and cellular responses to both homologous (Plasmodium) and heterologous antigens (e.g., vaccines). However, neither the underlying mechanisms nor the relative involvement of different types of immune cells in immunosuppression during malaria is well understood. Moreover, the implication of the parasite during the different stages of the modulation of immunity has not been addressed in detail. There is growing evidence of a role of immune regulators and cellular components in malaria that may lead to immunosuppression that needs further research. In this review, we summarize the current evidence on how malaria parasites may directly and indirectly induce immunosuppression and investigate the potential role of specific cell types, effector molecules and other immunoregulatory factors.
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Abdrabou W, Dieng MM, Diawara A, Sermé SS, Almojil D, Sombié S, Henry NB, Kargougou D, Manikandan V, Soulama I, Idaghdour Y. Metabolome modulation of the host adaptive immunity in human malaria. Nat Metab 2021; 3:1001-1016. [PMID: 34113019 DOI: 10.1038/s42255-021-00404-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 05/07/2021] [Indexed: 02/06/2023]
Abstract
Host responses to infection with the malaria parasite Plasmodium falciparum vary among individuals for reasons that are poorly understood. Here we reveal metabolic perturbations as a consequence of malaria infection in children and identify an immunosuppressive role of endogenous steroid production in the context of P. falciparum infection. We perform metabolomics on matched samples from children from two ethnic groups in West Africa, before and after infection with seasonal malaria. Analysing 306 global metabolomes, we identify 92 parasitaemia-associated metabolites with impact on the host adaptive immune response. Integrative metabolomic and transcriptomic analyses, and causal mediation and moderation analyses, reveal an infection-driven immunosuppressive role of parasitaemia-associated pregnenolone steroids on lymphocyte function and the expression of key immunoregulatory lymphocyte genes in the Gouin ethnic group. In children from the less malaria-susceptible Fulani ethnic group, we observe opposing responses following infection, consistent with the immunosuppressive role of endogenous steroids in malaria. These findings advance our understanding of P. falciparum pathogenesis in humans and identify potential new targets for antimalarial therapeutic interventions.
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Affiliation(s)
- Wael Abdrabou
- Program in Biology, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Department of Biology, New York University, New York, NY, USA
| | - Mame Massar Dieng
- Program in Biology, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Aïssatou Diawara
- Program in Biology, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Samuel Sindié Sermé
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Dareen Almojil
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Salif Sombié
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Noelie Bere Henry
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Désiré Kargougou
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Vinu Manikandan
- Program in Biology, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Youssef Idaghdour
- Program in Biology, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
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Identification of chlorophyll a-b binding protein AB96 as a novel TGFβ1 neutralizing agent. Sci Rep 2021; 11:7740. [PMID: 33833368 PMCID: PMC8032758 DOI: 10.1038/s41598-021-87454-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/15/2021] [Indexed: 11/12/2022] Open
Abstract
The discovery of compounds and proteins from plants has greatly contributed to modern medicine. Vernonia amygdalina Del. (Compositae) is used by humans and primates for a variety of conditions including parasitic infection. This paper describes the serendipitous discovery that V. amygdalina extract was able to bind to, and functionally inhibit, active TGFβ1. The binding agent was isolated and identified as chlorophyll a-b binding protein AB96. Given that active TGFβ1 contributes to the pathology of many infectious diseases, inhibiting these processes may explain some of the benefits associated with the ingestion of this species. This is the first plant-derived cytokine-neutralizing protein to be described and paves the way for further such discoveries.
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Lamsfus Calle C, Fendel R, Singh A, Richie TL, Hoffman SL, Kremsner PG, Mordmüller B. Expansion of Functional Myeloid-Derived Suppressor Cells in Controlled Human Malaria Infection. Front Immunol 2021; 12:625712. [PMID: 33815377 PMCID: PMC8017236 DOI: 10.3389/fimmu.2021.625712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/22/2021] [Indexed: 12/12/2022] Open
Abstract
Malaria can cause life-threatening complications which are often associated with inflammatory reactions. More subtle, but also contributing to the burden of disease are chronic, often subclinical infections, which result in conditions like anemia and immunologic hyporesponsiveness. Although very frequent, such infections are difficult to study in endemic regions because of interaction with concurrent infections and immune responses. In particular, knowledge about mechanisms of malaria-induced immunosuppression is scarce. We measured circulating immune cells by cytometry in healthy, malaria-naïve, adult volunteers undergoing controlled human malaria infection (CHMI) with a focus on potentially immunosuppressive cells. Infectious Plasmodium falciparum (Pf) sporozoites (SPZ) (PfSPZ Challenge) were inoculated during two independent studies to assess malaria vaccine efficacy. Volunteers were followed daily until parasites were detected in the circulation by RT-qPCR. This allowed us to analyze immune responses during pre-patency and at very low parasite densities in malaria-naïve healthy adults. We observed a consistent increase in circulating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) in volunteers who developed P. falciparum blood stage parasitemia. The increase was independent of preceding vaccination with a pre-erythrocytic malaria vaccine. PMN-MDSC were functional, they suppressed CD4+ and CD8+ T cell proliferation as shown by ex-vivo co-cultivation with stimulated T cells. PMN-MDSC reduced T cell proliferation upon stimulation by about 50%. Interestingly, high circulating PMN-MDSC numbers were associated with lymphocytopenia. The number of circulating regulatory T cells (Treg) and monocytic MDSC (M-MDSC) showed no significant parasitemia-dependent variation. These results highlight PMN-MDSC in the peripheral circulation as an early indicator of infection during malaria. They suppress CD4+ and CD8+ T cell proliferation in vitro. Their contribution to immunosuppression in vivo in subclinical and uncomplicated malaria will be the subject of further research. Pre-emptive antimalarial pre-treatment of vaccinees to reverse malaria-associated PMN-MDSC immunosuppression could improve vaccine response in exposed individuals.
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Affiliation(s)
| | - Rolf Fendel
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Anurag Singh
- Department of Pediatrics 1, University Children's Hospital Tübingen, Tübingen, Germany.,Institute for Clinical and Experimental Transfusion Medicine, University Hospital Tübingen, Tübingen, Germany
| | | | | | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
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12
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Mario-Vásquez JE, Naranjo-González CA, Montiel J, Zuluaga LM, Vásquez AM, Tobón-Castaño A, Bedoya G, Segura C. Association of variants in IL1B, TLR9, TREM1, IL10RA, and CD3G and Native American ancestry on malaria susceptibility in Colombian populations. INFECTION GENETICS AND EVOLUTION 2020; 87:104675. [PMID: 33316430 DOI: 10.1016/j.meegid.2020.104675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 11/19/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022]
Abstract
Host genetics is an influencing factor in the manifestation of infectious diseases. In this study, the association of mild malaria with 28 variants in 16 genes previously reported in other populations and/or close to ancestry-informative markers (AIMs) selected was evaluated in an admixed 736 Colombian population sample. Additionally, the effect of genetic ancestry on phenotype expression was explored. For this purpose, the ancestral genetic composition of Turbo and El Bagre was determined. A higher Native American ancestry trend was found in the population with lower malaria susceptibility [odds ratio (OR) = 0.416, 95% confidence interval (95% CI) = 0.234-0.740, P = 0.003]. Three AIMs presented significant associations with the disease phenotype (MID1752, MID921, and MID1586). The first two were associated with greater malaria susceptibility (D/D, OR = 2.23, 95% CI = 1.06-4.69, P = 0.032 and I/D-I/I, OR = 2.14, 95% CI = 1.18-3.87, P = 0.011, respectively), and the latter has a protective effect on the appearance of malaria (I/I, OR = 0.18, 95% CI = 0.08-0.40, P < 0.0001). After adjustment by age, sex, municipality, and genetic ancestry, genotype association analysis showed evidence of association with malaria susceptibility for variants in or near IL1B, TLR9, TREM1, IL10RA, and CD3G genes: rs1143629-IL1B (G/A-A/A, OR = 0.41, 95% CI = 0.21-0.78, P = 0.0051), rs352139-TLR9 (T/T, OR = 0.28, 95% CI = 0.11-0.72, P = 0.0053), rs352140-TLR9 (C/C, OR = 0.41, 95% CI = 0.20-0.87, P = 0.019), rs2234237-TREM1 (T/A-A/A, OR = 0.43, 95% CI = 0.23-0.79, P = 0.0056), rs4252246-IL10RA (C/A-A/A, OR = 2.11, 95% CI = 1.18-3.75, P = 0.01), and rs1561966-CD3G (A/A, OR = 0.20, 95% CI = 0.06-0.69, P = 0.0058). The results showed the participation of genes involved in immunological processes and suggested an effect of ancestral genetic composition over the traits analyzed. Compared to the paisa population (Antioquia), Turbo and El Bagre showed a strong decrease in European ancestry and an increase in African and Native American ancestries. Also, a novel association of two single nucleotide polymorphisms with malaria susceptibility was identified in this study.
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Affiliation(s)
- Jorge Eliécer Mario-Vásquez
- Grupo Genética Molecular (GENMOL), Universidad de Antioquia, Carrera 53 No. 61-30, Lab 430. Medellín, Colombia
| | | | - Jehidys Montiel
- Grupo Malaria-Facultad de Medicina, Universidad de Antioquia, Carrera 53 No. 61-30, Lab 610, Medellín, Colombia
| | - Lina M Zuluaga
- Grupo Malaria-Facultad de Medicina, Universidad de Antioquia, Carrera 53 No. 61-30, Lab 610, Medellín, Colombia
| | - Ana M Vásquez
- Grupo Malaria-Facultad de Medicina, Universidad de Antioquia, Carrera 53 No. 61-30, Lab 610, Medellín, Colombia
| | - Alberto Tobón-Castaño
- Grupo Malaria-Facultad de Medicina, Universidad de Antioquia, Carrera 53 No. 61-30, Lab 610, Medellín, Colombia
| | - Gabriel Bedoya
- Grupo Genética Molecular (GENMOL), Universidad de Antioquia, Carrera 53 No. 61-30, Lab 430. Medellín, Colombia
| | - Cesar Segura
- Grupo Malaria-Facultad de Medicina, Universidad de Antioquia, Carrera 53 No. 61-30, Lab 610, Medellín, Colombia.
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13
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Cai C, Hu Z, Yu X. Accelerator or Brake: Immune Regulators in Malaria. Front Cell Infect Microbiol 2020; 10:610121. [PMID: 33363057 PMCID: PMC7758250 DOI: 10.3389/fcimb.2020.610121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/09/2020] [Indexed: 12/15/2022] Open
Abstract
Malaria is a life-threatening infectious disease, affecting over 250 million individuals worldwide each year, eradicating malaria has been one of the greatest challenges to public health for a century. Growing resistance to anti-parasitic therapies and lack of effective vaccines are major contributing factors in controlling this disease. However, the incomplete understanding of parasite interactions with host anti-malaria immunity hinders vaccine development efforts to date. Recent studies have been unveiling the complexity of immune responses and regulators against Plasmodium infection. Here, we summarize our current understanding of host immune responses against Plasmodium-derived components infection and mainly focus on the various regulatory mechanisms mediated by recent identified immune regulators orchestrating anti-malaria immunity.
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Affiliation(s)
- Chunmei Cai
- Research Center for High Altitude Medicine, School of Medical, Qinghai University, Xining, China
- Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province, Qinghai University, Xining, China
| | - Zhiqiang Hu
- Department of Immunology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xiao Yu
- Department of Immunology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Lab of Single Cell Technology and Application, Southern Medical University, Guangzhou, China
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14
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Troye-Blomberg M, Arama C, Quin J, Bujila I, Östlund Farrants AK. What will studies of Fulani individuals naturally exposed to malaria teach us about protective immunity to malaria? Scand J Immunol 2020; 92:e12932. [PMID: 32652609 PMCID: PMC7583377 DOI: 10.1111/sji.12932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/18/2020] [Accepted: 07/06/2020] [Indexed: 12/27/2022]
Abstract
There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub‐Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide‐treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.
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Affiliation(s)
- Marita Troye-Blomberg
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Charles Arama
- Department of Epidemiology of Parasitic Diseases, International Center of Excellence in Research, Malaria Research and Training Centre, University of Sciences, Technique and Technology of Bamako, Bamako, Mali
| | - Jaclyn Quin
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.,CEITEC Masaryk University, Brno, Czech Republic
| | - Ioana Bujila
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.,Department of Microbiology, Public Health Agency of Sweden, Solna, Sweden
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15
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Mangano VD, Bianchi C, Ouedraogo M, Kabore Y, Corran P, Silva N, Sirima SB, Nebie I, Bruschi F, Modiano D. Antibody response to Schistosoma haematobium and other helminth species in malaria-exposed populations from Burkina Faso. Acta Trop 2020; 205:105381. [PMID: 32007449 DOI: 10.1016/j.actatropica.2020.105381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 10/25/2022]
Abstract
Infection with helminths in sub-Saharan Africa could modulate the immune response towards Plasmodium falciparum as well as susceptibility to malaria infection and disease. The aim of this study is to assess the antibody responses to helminths species in malaria-exposed populations from Burkina Faso. Plasma samples were collected in rural villages inhabited by Fulani, Mossi and Rimaibe communities, and IgG against parasitic helminths were measured by ELISA. The prevalence of IgG against antigens of Strongyloides stercoralis, Wuchereria bancrofti and Schistosoma haematobium (Soluble Egg Antigen, SEA) was 5%, 16% and 63% respectively, in line with estimates of infection prevalence in the region for the three parasites. Anti-SEA IgG prevalence was highest at 10-20 years of age, higher in males than females, and did not show differences between ethnic groups. However, the Fulani showed lower levels of anti-SEA IgG suggesting that lighter S. haematobium infections may occur in the ethnic group known for a marked lower susceptibility to P. falciparum. The present data support the use of serological methods for integrated surveillance of neglected tropical diseases such as soil-transmitted helminths, lymphatic filariasis and bilharzia. Furthermore, as helminth infections might promote downregulation of immune responses against intracellular pathogens, the observation of lower anti-SEA IgG levels in the malaria resistant Fulani population warrants further investigation into the immunological cross-talk between S. haematobium and P. falciparum in this geographical region.
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16
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The Human Spleen in Malaria: Filter or Shelter? Trends Parasitol 2020; 36:435-446. [PMID: 32298631 DOI: 10.1016/j.pt.2020.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 02/10/2020] [Accepted: 03/04/2020] [Indexed: 12/18/2022]
Abstract
The human spleen is an immune sentinel and controls red blood cell (RBC) quality. By mechanically retaining subsets of infected RBCs, the spleen may reduce the pace at which the parasite biomass increases before the adaptive immune response operates. Conversely, the spleen may contribute to malaria pathogenesis, particularly anemia that is associated with splenomegaly. Large spleens may also shelter parasites in chronic carriers. Upon treatment with artemisinins, the spleen clears circulating parasites by pitting and releases 'once-infected' RBCs in circulation. This triggers postartesunate delayed hemolysis and explains the long post-treatment positivity of histidine-rich protein 2 (HRP2)-based dipsticks. Importantly, splenic retention of RBCs also applies to gametocytes, the clearance of which may be enhanced by stiffening them with drugs, a potential way to block malaria transmission.
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17
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Abstract
Immunity to malaria has been linked to the availability and function of helper CD4+ T cells, cytotoxic CD8+ T cells and γδ T cells that can respond to both the asymptomatic liver stage and the symptomatic blood stage of Plasmodium sp. infection. These T cell responses are also thought to be modulated by regulatory T cells. However, the precise mechanisms governing the development and function of Plasmodium-specific T cells and their capacity to form tissue-resident and long-lived memory populations are less well understood. The field has arrived at a point where the push for vaccines that exploit T cell-mediated immunity to malaria has made it imperative to define and reconcile the mechanisms that regulate the development and functions of Plasmodium-specific T cells. Here, we review our current understanding of the mechanisms by which T cell subsets orchestrate host resistance to Plasmodium infection on the basis of observational and mechanistic studies in humans, non-human primates and rodent models. We also examine the potential of new experimental strategies and human infection systems to inform a new generation of approaches to harness T cell responses against malaria.
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18
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Gbedande K, Carpio VH, Stephens R. Using two phases of the CD4 T cell response to blood-stage murine malaria to understand regulation of systemic immunity and placental pathology in Plasmodium falciparum infection. Immunol Rev 2020; 293:88-114. [PMID: 31903675 PMCID: PMC7540220 DOI: 10.1111/imr.12835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/08/2019] [Accepted: 12/09/2019] [Indexed: 02/06/2023]
Abstract
Plasmodium falciparum infection and malaria remain a risk for millions of children and pregnant women. Here, we seek to integrate knowledge of mouse and human T helper cell (Th) responses to blood-stage Plasmodium infection to understand their contribution to protection and pathology. Although there is no complete Th subset differentiation, the adaptive response occurs in two phases in non-lethal rodent Plasmodium infection, coordinated by Th cells. In short, cellular immune responses limit the peak of parasitemia during the first phase; in the second phase, humoral immunity from T cell-dependent germinal centers is critical for complete clearance of rapidly changing parasite. A strong IFN-γ response kills parasite, but an excess of TNF compared with regulatory cytokines (IL-10, TGF-β) can cause immunopathology. This common pathway for pathology is associated with anemia, cerebral malaria, and placental malaria. These two phases can be used to both understand how the host responds to rapidly growing parasite and how it attempts to control immunopathology and variation. This dual nature of T cell immunity to Plasmodium is discussed, with particular reference to the protective nature of the continuous generation of effector T cells, and the unique contribution of effector memory T cells.
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Affiliation(s)
- Komi Gbedande
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Victor H Carpio
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
| | - Robin Stephens
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
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19
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Frimpong A, Kusi KA, Tornyigah B, Ofori MF, Ndifon W. Characterization of T cell activation and regulation in children with asymptomatic Plasmodium falciparum infection. Malar J 2018; 17:263. [PMID: 30005684 PMCID: PMC6045887 DOI: 10.1186/s12936-018-2410-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/07/2018] [Indexed: 02/08/2023] Open
Abstract
Background Asymptomatic Plasmodium infections are characterized by the absence of clinical disease and the ability to restrict parasite replication. Increasing levels of regulatory T cells (Tregs) in Plasmodium falciparum infections have been associated with the risk of developing clinical disease, suggesting that individuals with asymptomatic infections may have reduced Treg frequency. However, the relationship between Tregs, cellular activation and parasite control in asymptomatic malaria remains unclear. Methods In a cross-sectional study, the levels of Tregs and other T cell activation phenotypes were compared using flow cytometry in symptomatic, asymptomatic and uninfected children before and after stimulation with infected red blood cell lysates (iRBCs). In addition, the association between these T cell phenotypes and parasitaemia were investigated. Results In children with asymptomatic infections, levels of Tregs and activated T cells were comparable to those in healthy controls but significantly lower than those in symptomatic children. After iRBC stimulation, levels of Tregs remained lower for asymptomatic versus symptomatic children. In contrast, levels of activated T cells were higher for asymptomatic children. Strikingly, the pre-stimulation levels of two T cell activation phenotypes (CD8+CD69+ and CD8+CD25+CD69+) and the post-stimulation levels of two regulatory phenotypes (CD4+CD25+Foxp3+ and CD8+CD25+Foxp3+) were significantly positively correlated with and explained 68% of the individual variation in parasitaemia. A machine-learning model based on levels of these four phenotypes accurately distinguished between asymptomatic and symptomatic children (sensitivity = 86%, specificity = 94%), suggesting that these phenotypes govern the observed variation in disease status. Conclusion Compared to symptomatic P. falciparum infections, in children asymptomatic infections are characterized by lower levels of Tregs and activated T cells, which are associated with lower parasitaemia. The results indicate that T cell regulatory and activation phenotypes govern both parasitaemia and disease status in paediatric malaria in the studied sub-Saharan African population. Electronic supplementary material The online version of this article (10.1186/s12936-018-2410-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Augustina Frimpong
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, P. O. Box LG 54, Accra, Ghana. .,Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P.O. Box LG 581, Accra, Ghana. .,African Institute for Mathematical Sciences, P.O. Box DL 676, Cape-Coast, Ghana.
| | - Kwadwo Asamoah Kusi
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, P. O. Box LG 54, Accra, Ghana.,Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P.O. Box LG 581, Accra, Ghana
| | - Bernard Tornyigah
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P.O. Box LG 581, Accra, Ghana
| | - Michael Fokuo Ofori
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, P. O. Box LG 54, Accra, Ghana.,Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P.O. Box LG 581, Accra, Ghana
| | - Wilfred Ndifon
- African Institute for Mathematical Sciences, P.O. Box DL 676, Cape-Coast, Ghana. .,African Institute for Mathematical Sciences, University of Stellenbosch, 7 Melrose Rd, Muizenberg, Cape Town, 7945, South Africa.
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20
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Sanchez-Mazas A, Černý V, Di D, Buhler S, Podgorná E, Chevallier E, Brunet L, Weber S, Kervaire B, Testi M, Andreani M, Tiercy JM, Villard J, Nunes JM. The HLA-B landscape of Africa: Signatures of pathogen-driven selection and molecular identification of candidate alleles to malaria protection. Mol Ecol 2017; 26:6238-6252. [PMID: 28950417 DOI: 10.1111/mec.14366] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/11/2017] [Indexed: 11/30/2022]
Abstract
Human leukocyte antigen (HLA) genes play a key role in the immune response to infectious diseases, some of which are highly prevalent in specific environments, like malaria in sub-Saharan Africa. Former case-control studies showed that one particular HLA-B allele, B*53, was associated with malaria protection in Gambia, but this hypothesis was not tested so far within a population genetics framework. In this study, our objective was to assess whether pathogen-driven selection associated with malaria contributed to shape the HLA-B genetic landscape of Africa. To that aim, we first typed the HLA-A and -B loci in 484 individuals from 11 populations living in different environments across the Sahel, and we analysed these data together with those available for 29 other populations using several approaches including linear modelling on various genetic, geographic and environmental parameters. In addition to relevant signatures of populations' demography and migrations history in the genetic differentiation patterns of both HLA-A and -B loci, we found that the frequencies of three HLA alleles, B*53, B*78 and A*74, were significantly associated with Plasmodium falciparum malaria prevalence, suggesting their increase through pathogen-driven selection in malaria-endemic environments. The two HLA-B alleles were further identified, by high-throughput sequencing, as B*53:01:01 (in putative linkage disequilibrium with one HLA-C allele, C*04:01:01:01) and B*78:01 in all but one individuals tested, making them appropriate candidates to malaria protection. These results highlight the role of environmental factors in the evolution of the HLA polymorphism and open key perspectives for functional studies focusing on HLA peptide-binding properties.
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Affiliation(s)
- Alicia Sanchez-Mazas
- Department of Genetics and Evolution - Anthropology Unit, Laboratory of Anthropology, Genetics and Peopling History (AGP), University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva (IGE3), Geneva, Switzerland
| | - Viktor Černý
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
| | - Da Di
- Department of Genetics and Evolution - Anthropology Unit, Laboratory of Anthropology, Genetics and Peopling History (AGP), University of Geneva, Geneva, Switzerland
| | - Stéphane Buhler
- Department of Genetics and Evolution - Anthropology Unit, Laboratory of Anthropology, Genetics and Peopling History (AGP), University of Geneva, Geneva, Switzerland.,Department of Genetic and Laboratory Medicine, Transplantation Immunology Unit and National Reference Laboratory for Histocompatibility (UIT/LNRH), Geneva University Hospitals, Geneva, Switzerland
| | - Eliška Podgorná
- Department of the Archaeology of Landscape and Archaeobiology, Archaeogenetics Laboratory, Institute of Archaeology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Elodie Chevallier
- Department of Genetics and Evolution - Anthropology Unit, Laboratory of Anthropology, Genetics and Peopling History (AGP), University of Geneva, Geneva, Switzerland
| | - Lydie Brunet
- Department of Genetics and Evolution - Anthropology Unit, Laboratory of Anthropology, Genetics and Peopling History (AGP), University of Geneva, Geneva, Switzerland.,Department of Genetic and Laboratory Medicine, Transplantation Immunology Unit and National Reference Laboratory for Histocompatibility (UIT/LNRH), Geneva University Hospitals, Geneva, Switzerland
| | - Stephan Weber
- Department of Genetics and Evolution - Anthropology Unit, Laboratory of Anthropology, Genetics and Peopling History (AGP), University of Geneva, Geneva, Switzerland
| | - Barbara Kervaire
- Department of Genetic and Laboratory Medicine, Transplantation Immunology Unit and National Reference Laboratory for Histocompatibility (UIT/LNRH), Geneva University Hospitals, Geneva, Switzerland
| | - Manuela Testi
- Laboratory of Immunogenetics and Transplant Biology, IME Foundation, Policlinic of the University of Tor Vergata, Rome, Italy
| | - Marco Andreani
- Laboratory of Immunogenetics and Transplant Biology, IME Foundation, Policlinic of the University of Tor Vergata, Rome, Italy
| | - Jean-Marie Tiercy
- Institute of Genetics and Genomics in Geneva (IGE3), Geneva, Switzerland.,Department of Genetic and Laboratory Medicine, Transplantation Immunology Unit and National Reference Laboratory for Histocompatibility (UIT/LNRH), Geneva University Hospitals, Geneva, Switzerland
| | - Jean Villard
- Institute of Genetics and Genomics in Geneva (IGE3), Geneva, Switzerland.,Department of Genetic and Laboratory Medicine, Transplantation Immunology Unit and National Reference Laboratory for Histocompatibility (UIT/LNRH), Geneva University Hospitals, Geneva, Switzerland
| | - José Manuel Nunes
- Department of Genetics and Evolution - Anthropology Unit, Laboratory of Anthropology, Genetics and Peopling History (AGP), University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva (IGE3), Geneva, Switzerland
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21
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Quin JE, Bujila I, Chérif M, Sanou GS, Qu Y, Vafa Homann M, Rolicka A, Sirima SB, O'Connell MA, Lennartsson A, Troye-Blomberg M, Nebie I, Östlund Farrants AK. Major transcriptional changes observed in the Fulani, an ethnic group less susceptible to malaria. eLife 2017; 6:29156. [PMID: 28923166 PMCID: PMC5629023 DOI: 10.7554/elife.29156] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/05/2017] [Indexed: 12/12/2022] Open
Abstract
The Fulani ethnic group has relatively better protection from Plasmodium falciparum malaria, as reflected by fewer symptomatic cases of malaria, lower infection rates, and lower parasite densities compared to sympatric ethnic groups. However, the basis for this lower susceptibility to malaria by the Fulani is unknown. The incidence of classic malaria resistance genes are lower in the Fulani than in other sympatric ethnic populations, and targeted SNP analyses of other candidate genes involved in the immune response to malaria have not been able to account for the observed difference in the Fulani susceptibility to P.falciparum. Therefore, we have performed a pilot study to examine global transcription and DNA methylation patterns in specific immune cell populations in the Fulani to elucidate the mechanisms that confer the lower susceptibility to P.falciparum malaria. When we compared uninfected and infected Fulani individuals, in contrast to uninfected and infected individuals from the sympatric ethnic group Mossi, we observed a key difference: a strong transcriptional response was only detected in the monocyte fraction of the Fulani, where over 1000 genes were significantly differentially expressed upon P.falciparum infection.
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Affiliation(s)
- Jaclyn E Quin
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Ioana Bujila
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Mariama Chérif
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.,Université Polytechnique de Bobo-Dioulasso, Bobo-Dioulasso, Burkina Faso
| | - Guillaume S Sanou
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Ying Qu
- Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden
| | - Manijeh Vafa Homann
- Unit of Infectious Diseases, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Anna Rolicka
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - Andreas Lennartsson
- Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden
| | - Marita Troye-Blomberg
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Issa Nebie
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
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Regulatory T cells impede acute and long-term immunity to blood-stage malaria through CTLA-4. Nat Med 2017; 23:1220-1225. [PMID: 28892065 DOI: 10.1038/nm.4395] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/05/2017] [Indexed: 02/07/2023]
Abstract
Malaria, caused by the protozoan Plasmodium, is a devastating mosquito-borne disease with the potential to affect nearly half the world's population. Despite mounting substantial T and B cell responses, humans fail to efficiently control blood-stage malaria or develop sterilizing immunity to reinfections. Although forkhead box P3 (FOXP3)+CD4+ regulatory T (Treg) cells form a part of these responses, their influence remains disputed and their mode of action is unknown. Here we show that Treg cells expand in both humans and mice in blood-stage malaria and interfere with conventional T helper cell responses and follicular T helper (TFH)-B cell interactions in germinal centers. Mechanistically, Treg cells function in a critical temporal window to impede protective immunity through cytotoxic-T-lymphocyte-associated protein-4 (CTLA-4). Targeting Treg cells or CTLA-4 in this precise window accelerated parasite clearance and generated species-transcending immunity to blood-stage malaria in mice. Our study uncovers a critical mechanism of immunosuppression associated with blood-stage malaria that delays parasite clearance and prevents development of potent adaptive immunity to reinfection. These data also reveal a temporally discrete and potentially therapeutically amenable functional role for Treg cells and CTLA-4 in limiting antimalarial immunity.
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Stephen-Victor E, Bosschem I, Haesebrouck F, Bayry J. The Yin and Yang of regulatory T cells in infectious diseases and avenues to target them. Cell Microbiol 2017; 19. [DOI: 10.1111/cmi.12746] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Emmanuel Stephen-Victor
- Institut National de la Santé et de la Recherche Médicale; Paris France
- Centre de Recherche des Cordeliers; Equipe-Immunopathologie et Immunointervention Thérapeutique; Paris France
- Sorbonne Universités; Université Pierre et Marie Curie; Paris France
| | - Iris Bosschem
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine; Ghent University; Merelbeke Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine; Ghent University; Merelbeke Belgium
| | - Jagadeesh Bayry
- Institut National de la Santé et de la Recherche Médicale; Paris France
- Centre de Recherche des Cordeliers; Equipe-Immunopathologie et Immunointervention Thérapeutique; Paris France
- Sorbonne Universités; Université Pierre et Marie Curie; Paris France
- Université Paris Descartes; Sorbonne Paris Cité; Paris France
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Endo N, Eltahir EAB. Environmental determinants of malaria transmission in African villages. Malar J 2016; 15:578. [PMID: 27903266 PMCID: PMC5131557 DOI: 10.1186/s12936-016-1633-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 11/23/2016] [Indexed: 12/02/2022] Open
Abstract
Background Malaria transmission is complex, involving a range of hydroclimatological, biological, and environmental processes. The high degree of non-linearity in these processes makes it difficult to predict and intervene against malaria. This study seeks both to define a minimal number of malaria transmission determinants, and to provide a theoretical basis for sustainable environmental manipulation to prevent malaria transmission. Methods Using a field-tested mechanistic malaria model, HYDREMATS, a theoretical study was conducted under hypothetical conditions. Simulations were conducted with a range of hydroclimatological and environmental conditions: temperature (t), length of wet season (Twet), storm inter-arrival time (Tint), persistence of vector breeding pools (Ton), and distribution of houses from breeding pools and from each other (Xdist and Ydist, respectively). Based on the theoretical study, a malaria time scale, To, and a predictive theory of malaria transmission were introduced. The performance of the predictive theory was compared against the observational malaria transmission data in West Africa. Population density was used to estimate the scale that describes the spatial distribution of houses. Results The predictive theory shows a universality in malaria endemic conditions when plotted using two newly-introduced dimension-less parameters. The projected malaria transmission potential compared well with the observation data, and the apparent differences were discussed. The results illustrate the importance of spatial aspects in malaria transmission. Conclusions The predictive theory is useful in measuring malaria transmission potential, and it can also provide guidelines on how to plan the layout of human habitats in order to prevent endemic malaria. Malaria-resistant villages can be designed by locating houses further than critical distances away from breeding pools or by removing pools within a critical distance from houses; the critical distance is described in the context of local climatology and hydrology. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1633-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Noriko Endo
- Ralph M. Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Elfatih A B Eltahir
- Ralph M. Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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25
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Van Braeckel-Budimir N, Kurup SP, Harty JT. Regulatory issues in immunity to liver and blood-stage malaria. Curr Opin Immunol 2016; 42:91-97. [PMID: 27351448 DOI: 10.1016/j.coi.2016.06.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 06/10/2016] [Accepted: 06/15/2016] [Indexed: 02/01/2023]
Abstract
T cells play a major role in control of both blood and liver stage of plasmodium infection. While immunization with certain attenuated whole-parasite vaccines that are attenuated at the liver stage of the infection induces protective T cell responses, even multiple exposures to natural infection in endemic areas do not lead to stable T cell memory or humoral immunity and sterilizing protection. One of the key differences between vaccination and natural exposure is the absence of blood stage during vaccination. Here we will discuss possible immunoregulatory strategies employed by blood stage of malaria leading to generation of severely compromised T cell and humoral immune responses and subsequent lack of sterilizing immunity.
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Affiliation(s)
| | - Samarchith P Kurup
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
| | - John T Harty
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA; Department of Pathology, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA 52242, USA.
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26
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Cherif M, Amoako-Sakyi D, Dolo A, Pearson JO, Gyan B, Obiri-Yeboah D, Nebie I, Sirima SB, Doumbo O, Troye-Blomberg M, Bakary M. Distribution of FcγR gene polymorphisms among two sympatric populations in Mali: differing allele frequencies, associations with malariometric indices and implications for genetic susceptibility to malaria. Malar J 2016; 15:29. [PMID: 26785902 PMCID: PMC4717667 DOI: 10.1186/s12936-015-1082-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/31/2015] [Indexed: 11/18/2022] Open
Abstract
Background Genetic polymorphisms in the complex gene cluster encoding human Fc-gamma receptors (FcγRs) may influence malaria susceptibility and pathogenesis. Studying genetic susceptibility to malaria is ideal among sympatric populations because the distribution of polymorphic genes among such populations can help in the identification malaria candidate genes. This study determined the distribution of three FcyRs single nucleotide polymorphisms (SNPs) (FcγRIIB-rs1050519, FcγRIIC-rs3933769 and FcγRIIIA-rs396991) among sympatric Fulani and Dogon children with uncomplicated malaria. The association of these SNPs with clinical, malariometric and immunological indices was also tested. Methods This study involved 242 Fulani and Dogon volunteers from Mali age under 15 years. All SNPs were genotyped with predesigned TaqMan® SNP Genotyping Assays. Genotypic and allelic distribution of SNPs was compared across ethnic groups using the Fisher exact test. Variations in clinical, malariometric and immunologic indices between groups were tested with Kruskal–Wallis H, Mann–Whitney U test and Fisher exact test where appropriate. Results The study confirmed known malariometric and immunologic differences between sympatric Fulani and non-Fulani tribes. Parasite density was lower in the Fulani than the Dogon (p < 0.0001). The mutant allele of FcγRIIC (rs3933769) was found more frequently in the Fulani than the Dogon (p < 0.0001) while that of FcγRIIIA (rs396991) occurred less frequently in the Fulani than Dogon (p = 0.0043). The difference in the mutant allele frequency of FcγRIIB (rs1050519) between the two ethnic groups was however not statistically significant (p = 0.064). The mutant allele of rs396991 was associated with high malaria-specific IgG1 and IgG3 in the entire study population and Dogon tribe, p = 0.023 and 0.015, respectively. Parasite burden was lower in carriers of the FcγRIIC (rs3933769) mutant allele than non-carriers in the entire study population (p < 0.0001). Carriers of this allele harboured less than half the parasites found in non-carriers. Conclusion Differences in the allelic frequencies of rs3933769 and rs396991 among Fulani and Dogon indirectly suggest that these SNPs may influence malaria susceptibility and pathogenesis in the study population. The high frequency of the FcγRIIC (rs3933769) mutant allele in the Fulani and its subsequent association with low parasite burden in the entire study population is noteworthy.
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Affiliation(s)
- Mariama Cherif
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso. .,Polytechnic University of Bobo Dioulasso, Bobo Dioulasso, Burkina Faso.
| | - Daniel Amoako-Sakyi
- Department of Microbiology and Immunology, College of Health and Allied Sciences, School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana. .,Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana.
| | - Amagana Dolo
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odonto-Stomatology, Malaria Research and Training Centre, USTTB, Bamako, Mali.
| | - Jan-Olov Pearson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
| | - Ben Gyan
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana.
| | - Dorcas Obiri-Yeboah
- Department of Microbiology and Immunology, College of Health and Allied Sciences, School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana.
| | - Issa Nebie
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.
| | - Ogobara Doumbo
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odonto-Stomatology, Malaria Research and Training Centre, USTTB, Bamako, Mali.
| | - Marita Troye-Blomberg
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
| | - Maiga Bakary
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Odonto-Stomatology, Malaria Research and Training Centre, USTTB, Bamako, Mali.
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Abstract
Naturally acquired immunity to the blood-stage of the malaria parasite develops slowly in areas of high endemicity, but is not sterilizing. It manifests as a reduction in parasite density and clinical symptoms. Immunity as a result of blood-stage vaccination has not yet been achieved in humans, although there are many animal models where vaccination has been successful. The development of a blood-stage vaccine has been complicated by a number of factors including limited knowledge of human-parasite interactions and which antigens and immune responses are critical for protection. Opinion is divided as to whether this vaccine should aim to accelerate the acquisition of responses acquired following natural exposure, or whether it should induce a different response. Animal and experimental human models suggest that cell-mediated immune responses can control parasite growth, but these responses can also contribute to significant immunopathology if unregulated. They are largely ignored in most blood-stage malaria vaccine development strategies. Here, we discuss key observations relating to cell-mediated immune responses in the context of experimental human systems and field studies involving naturally exposed individuals and how this may inform the development of a blood-stage malaria vaccine.
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28
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Jaafar RM, Chettri JK, Dalsgaard I, Al-Jubury A, Kania PW, Skov J, Buchmann K. Effects of adjuvant Montanide™ ISA 763 A VG in rainbow trout injection vaccinated against Yersinia ruckeri. FISH & SHELLFISH IMMUNOLOGY 2015; 47:797-806. [PMID: 26492991 DOI: 10.1016/j.fsi.2015.10.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 05/04/2023]
Abstract
Enteric redmouth disease (ERM) caused by the fish pathogen Yersinia ruckeri is a major threat to freshwater production of rainbow trout (Oncorhynchus mykiss) throughout all life stages. Injection vaccination of rainbow trout against Y. ruckeri infection has been shown to confer better protection compared to the traditionally applied immersion vaccination. It may be hypothesized, based on experience from other vaccines, that adjuvants may increase the protective level of ERM injection vaccines even more. Controlled comparative vaccination studies have been performed to investigate effects of the oil adjuvant Montanide™ ISA 763 A VG (Seppic) when added to an experimental Y. ruckeri bacterin (containing both biotype 1 and 2 of serotype O1). A total of 1000 fish with mean weight 19 g was divided into five different groups (in duplicated tanks 2 × 100 fish per group) 1) non-vaccinated control fish (NonVac), 2) fish injected with a commercial vaccine (AquaVac(®) Relera™) (ComVac), 3) fish injected with an experimental vaccine (ExpVac), 4) fish injected with an experimental vaccine + adjuvant (ExpVacAdj) and 5) fish injected with adjuvant alone (Adj). Injection of the experimental vaccine (both adjuvanted and non-adjuvanted) induced a significantly higher antibody (IgM) level, increased occurrence of IgM(+) cells in spleen tissue and significant up-regulation of several immune genes. Additional experiments using a higher challenge dosage suggested an immune enhancing effect of the adjuvant as the challenge produced 100% mortality in the NonVac group, 60% mortality in both of ComVac and Adj groups and only 13 and 2.5% mortalities in the ExpVac and the ExpVacAdj groups, respectively.
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Affiliation(s)
- Rzgar M Jaafar
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark.
| | - Jiwan K Chettri
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Inger Dalsgaard
- National Veterinary Institute, Technical University of Denmark, Frederiksberg C, Denmark
| | - Azmi Al-Jubury
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Per W Kania
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Jakob Skov
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Kurt Buchmann
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
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29
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Nyirenda TS, Molyneux ME, Kenefeck R, Walker LSK, MacLennan CA, Heyderman RS, Mandala WL. T-Regulatory Cells and Inflammatory and Inhibitory Cytokines in Malawian Children Residing in an Area of High and an Area of Low Malaria Transmission During Acute Uncomplicated Malaria and in Convalescence. J Pediatric Infect Dis Soc 2015; 4:232-41. [PMID: 26335932 PMCID: PMC4554200 DOI: 10.1093/jpids/piu140] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 12/10/2014] [Indexed: 11/13/2022]
Abstract
BACKGROUND Malaria still infects many Malawian children, and it is a cause of death in some of them. Regulatory T cells (Tregs) help in negating immune-related pathology, it but can also favor multiplication of malaria parasites. The question remains whether children recovering from uncomplicated malaria (UCM) have higher Tregs and interleukin (IL)-10 levels in convalescence. METHODS We recruited children between the ages of 6 and 60 months presenting with acute UCM in Blantyre (low transmission area) and Chikwawa (high transmission area). We observed the children after 1 month and 3 months and analyzed their blood samples for parasitemia, lymphocyte subsets, and levels of the cytokines interferon (IFN)-γ, IL-10, and transforming growth factor (TGF)-β. Blood samples from age-matched controls were also analyzed for the same parameters. RESULTS Compared with controls, acute UCM was associated with mild lymphopenia, splenomegaly, and high levels of IFN-γ, tumor necrosis factor-α, and IL-10, which normalized in convalescence. In Chikwawa, Treg counts were significantly (P < .0001) higher in convalescence compared with acute disease, whereas in Blantyre, these were as low as in healthy controls both during acute disease and in convalescence. Blantyre had a higher percentage of parasiteamic children (15% versus 12%) in convalescence compared with Chikwawa, but none of these developed symptomatic malaria during the study duration. Concentrations of TGF-β were higher at time points for the study participants and in controls from Blantyre compared with those recruited in Chikwawa. CONCLUSIONS The high transmission area was associated with high Tregs counts and IL-10 concentrations in convalescence, which could have an effect on parasite clearance. We recommend that children recovering from UCM, especially those from high transmission area, should sleep under insecticide-treated nets, be screened for parasitemia, and a provision of antimalarial prophylaxis should be considered.
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Affiliation(s)
- Tonney S. Nyirenda
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre
| | - Malcolm E. Molyneux
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre,Liverpool School of Tropical Medicine, United Kingdom
| | - Rupert Kenefeck
- Institute of Immunity and Transplantation, University College London, Division of Infection and Immunity, United Kingdom
| | - Lucy S. K. Walker
- Institute of Immunity and Transplantation, University College London, Division of Infection and Immunity, United Kingdom
| | - Calman A. MacLennan
- The Medical Research Council Centre for Immune Regulation and Clinical Immunology, Service, School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, United Kingdom
| | - Robert S. Heyderman
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre,Liverpool School of Tropical Medicine, United Kingdom
| | - Wilson L. Mandala
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre,Basic Medical Sciences Department, College of Medicine, Blantyre, Malawi
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Maazoun F, Deschamps O, Barros-Kogel E, Ngwem E, Fauchet N, Buffet P, Froissart A. [Hyper-reactive malarial splenomegaly]. Rev Med Interne 2015; 36:753-9. [PMID: 26119345 DOI: 10.1016/j.revmed.2015.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 04/25/2015] [Accepted: 06/02/2015] [Indexed: 12/18/2022]
Abstract
Hyper-reactive malarial splenomegaly is a rare and severe form of chronic malaria. This condition is a common cause of splenomegaly in endemic areas. The pathophysiology of hyper-reactive malarial splenomegaly involves an intense immune reaction (predominantly B cell-driven) to repeated/chronic infections with Plasmodium sp. The diagnosis may be difficult, due to a poorly specific clinical presentation (splenomegaly, fatigue, cytopenias), a long delay between residence in a malaria-endemic area and onset of symptoms, and a frequent absence of parasites on conventional thin and thick blood smears. A strongly contributive laboratory parameter is the presence of high levels of total immunoglobulin M. When the diagnostic of hyper-reactive malarial splenomegaly is considered, search for anti-Plasmodium antibodies and Plasmodium nucleic acids (genus and species) by PCR is useful. Diagnosis of hyper-reactive malarial splenomegaly relies on the simultaneous presence of epidemiological, clinical, biological and follow-up findings. Regression of both splenomegaly and hypersplenism following antimalarial therapy allows the differential diagnosis with splenic lymphoma, a common complication of hyper-reactive malarial splenomegaly. Although rare in Western countries, hyper-reactive malarial splenomegaly deserves increased medical awareness to reduce the incidence of incorrect diagnosis, to prevent progression to splenic lymphoma and to avoid splenectomy.
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Affiliation(s)
- F Maazoun
- Service de médecine interne, centre hospitalier intercommunal de Créteil, 40, avenue de Verdun, 94010 Créteil cedex, France
| | - O Deschamps
- Service de médecine interne, centre hospitalier intercommunal de Créteil, 40, avenue de Verdun, 94010 Créteil cedex, France
| | - E Barros-Kogel
- Service de médecine interne, centre hospitalier intercommunal de Créteil, 40, avenue de Verdun, 94010 Créteil cedex, France
| | - E Ngwem
- Service de médecine interne, centre hospitalier intercommunal de Créteil, 40, avenue de Verdun, 94010 Créteil cedex, France
| | - N Fauchet
- Service de microbiologie, centre hospitalier intercommunal de Créteil, 94010 Créteil, France
| | - P Buffet
- Service de parasitologie, CHU Pitié-Salpêtrière, AP-HP, 75013 Paris, France; Laboratoire d'excellence GR-Ex, 75015 Paris, France
| | - A Froissart
- Service de médecine interne, centre hospitalier intercommunal de Créteil, 40, avenue de Verdun, 94010 Créteil cedex, France.
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Arama C, Maiga B, Dolo A, Kouriba B, Traoré B, Crompton PD, Pierce SK, Troye-Blomberg M, Miller LH, Doumbo OK. Ethnic differences in susceptibility to malaria: what have we learned from immuno-epidemiological studies in West Africa? Acta Trop 2015; 146:152-6. [PMID: 25820030 DOI: 10.1016/j.actatropica.2015.03.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/05/2015] [Accepted: 03/19/2015] [Indexed: 01/10/2023]
Abstract
There are many fundamental aspects of the immunobiology of Plasmodium falciparum infections that are not fully understood, therefore limiting our comprehension of how people become immune to malaria and why some ethnic groups living in malaria endemic areas are less susceptible than others. The complexity of parasite-host interactions and the genetic diversity of the parasites as well as the human host complicate our strategy to address this issue. In this mini-review we discuss and summarize what we have learned about African ethnic differences in susceptibility to malaria from immuno-epidemiological studies. Additionally, we suggest research topics that might be of great value for dissecting the mechanisms of protection by providing new insights into molecular interactions between the parasite and the host.
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32
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Boer MC, Joosten SA, Ottenhoff THM. Regulatory T-Cells at the Interface between Human Host and Pathogens in Infectious Diseases and Vaccination. Front Immunol 2015; 6:217. [PMID: 26029205 PMCID: PMC4426762 DOI: 10.3389/fimmu.2015.00217] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/20/2015] [Indexed: 12/20/2022] Open
Abstract
Regulatory T-cells (Tregs) act at the interface of host and pathogen interactions in human infectious diseases. Tregs are induced by a wide range of pathogens, but distinct effects of Tregs have been demonstrated for different pathogens and in different stages of infection. Moreover, Tregs that are induced by a specific pathogen may non-specifically suppress immunity against other microbes and parasites. Thus, Treg effects need to be assessed not only in homologous but also in heterologous infections and vaccinations. Though Tregs protect the human host against excessive inflammation, they probably also increase the risk of pathogen persistence and chronic disease, and the possibility of disease reactivation later in life. Mycobacterium leprae and Mycobacterium tuberculosis, causing leprosy and tuberculosis, respectively, are among the most ancient microbes known to mankind, and are master manipulators of the immune system toward tolerance and pathogen persistence. The majority of mycobacterial infections occur in settings co-endemic for viral, parasitic, and (other) bacterial coinfections. In this paper, we discuss recent insights in the activation and activity of Tregs in human infectious diseases, with emphasis on early, late, and non-specific effects in disease, coinfections, and vaccination. We highlight mycobacterial infections as important models of modulation of host responses and vaccine-induced immunity by Tregs.
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Affiliation(s)
- Mardi C Boer
- Department of Infectious Diseases, Leiden University Medical Center , Leiden , Netherlands
| | - Simone A Joosten
- Department of Infectious Diseases, Leiden University Medical Center , Leiden , Netherlands
| | - Tom H M Ottenhoff
- Department of Infectious Diseases, Leiden University Medical Center , Leiden , Netherlands
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Pinder M, Jawara M, Jarju LBS, Salami K, Jeffries D, Adiamoh M, Bojang K, Correa S, Kandeh B, Kaur H, Conway DJ, D'Alessandro U, Lindsay SW. Efficacy of indoor residual spraying with dichlorodiphenyltrichloroethane against malaria in Gambian communities with high usage of long-lasting insecticidal mosquito nets: a cluster-randomised controlled trial. Lancet 2015; 385:1436-46. [PMID: 25498847 DOI: 10.1016/s0140-6736(14)61007-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Although many malaria control programmes in sub-Saharan Africa use indoor residual spraying with long-lasting insecticidal nets (LLINs), the two studies assessing the benefit of the combination of these two interventions gave conflicting results. We aimed to assess whether the addition of indoor residual spraying to LLINs provided a significantly different level of protection against clinical malaria in children or against house entry by vector mosquitoes. METHODS In this two-arm cluster, randomised, controlled efficacy trial we randomly allocated clusters of Gambian villages using a computerised algorithm to LLINs alone (n=35) or indoor residual spraying with dichlorodiphenyltrichloroethane plus LLINs (n=35). In each cluster, 65-213 children, aged 6 months to 14 years, were surveyed at the start of the 2010 transmission season and followed in 2010 and 2011 by passive case detection for clinical malaria. Exposure to parasite transmission was assessed by collection of vector mosquitoes with both light and exit traps indoors. Primary endpoints were the incidence of clinical malaria assessed by passive case detection and number of Anopheles gambiae sensu lato mosquitoes collected per light trap per night. Intervention teams had no role in data collection and the data collection teams were not informed of the spray status of villages. The trial is registered at the ISRCTN registry, number ISRCTN01738840. FINDINGS LLIN coverage in 2011 was 3510 (93%) of 3777 children in the indoor residual spraying plus LLIN group and 3622 (95.5%) of 3791 in the LLIN group. In 2010, 7845 children were enrolled, 7829 completed passive case detection, and 7697 (98%) had complete clinical and covariate data. In 2011, 7009 children remained in the study, 648 more were enrolled, 7657 completed passive case detection, and 7545 (98.5%) had complete data. Indoor residual spraying coverage per cluster was more than 80% for both years in the indoor residual spraying plus LLIN group. Incidence of clinical malaria was 0.047 per child-month at risk in the LLIN group and 0.044 per child-month at risk in the indoor residual spraying plus LLIN group in 2010, and 0.032 per child-month at risk in the LLIN group and 0.034 per child-month at risk in the indoor residual spraying plus LLIN group in 2011. The incident rate ratio was 1.08 (95% CI 0.80-1.46) controlling for confounders and cluster by mixed-effect negative binomial regression on all malaria attacks for both years. No significant difference was recorded in the density of vector mosquitoes caught in light traps in houses over the two transmission seasons; the mean number of A gambiae sensu lato mosquitoes per trap per night was 6.7 (4.0-10.1) in the LLIN group and 4.5 (2.4-7.4) in the indoor residual spraying plus LLIN group (p=0.281 in the random-effects linear regression model). INTERPRETATION We identified no significant difference in clinical malaria or vector density between study groups. In this area with high LLIN coverage, moderate seasonal transmission, and susceptible vectors, indoor residual spraying did not provide additional benefit. FUNDING UK Medical Research Council.
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Affiliation(s)
- Margaret Pinder
- Medical Research Council Unit, Banjul, The Gambia; London School of Hygiene and Tropical Medicine, London, UK; Durham University, Durham, UK
| | - Musa Jawara
- Medical Research Council Unit, Banjul, The Gambia
| | | | | | | | | | | | - Simon Correa
- Medical Research Council Unit, Banjul, The Gambia
| | - Balla Kandeh
- National Malaria Control Programme, Banjul, The Gambia
| | | | - David J Conway
- Medical Research Council Unit, Banjul, The Gambia; London School of Hygiene and Tropical Medicine, London, UK
| | - Umberto D'Alessandro
- Medical Research Council Unit, Banjul, The Gambia; Institute of Tropical Medicine, Antwerp, Belgium
| | - Steve W Lindsay
- London School of Hygiene and Tropical Medicine, London, UK; Durham University, Durham, UK.
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Lopera-Mesa TM, Doumbia S, Konaté D, Anderson JM, Doumbouya M, Keita AS, Diakité SAS, Traoré K, Krause MA, Diouf A, Moretz SE, Tullo GS, Miura K, Gu W, Fay MP, Taylor SM, Long CA, Diakité M, Fairhurst RM. Effect of red blood cell variants on childhood malaria in Mali: a prospective cohort study. Lancet Haematol 2015; 2:e140-9. [PMID: 26687956 PMCID: PMC4418020 DOI: 10.1016/s2352-3026(15)00043-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 02/27/2015] [Accepted: 02/27/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND Red blood cell variants protect African children from severe falciparum malaria. However, their individual and interactive effects on mild disease and parasite density, and their modification by age-dependent immunity, are poorly understood. In this study, we address these knowledge gaps in a prospective cohort study of malaria risk and Plasmodium falciparum densities in Malian children. METHODS The Kenieroba Innate Defense Study for Malaria (KIDS-Malaria) was a 4-year prospective cohort study of children aged 6 months to 17 years undertaken in Mali between 2008 and 2011. Red blood cell variants were haemoglobin S (HbS), haemoglobin C (HbC), α thalassaemia, ABO blood groups, and glucose-6-phosphate dehydrogenase (G6PD) deficiency encoded by the X-linked A- allele. The primary outcome was malaria incidence, measured as the number of uncomplicated or severe malaria episodes over time. The secondary outcome was parasite density at the time of a malaria episode. We modelled incidence rate ratios with quasi-Poisson regression and we analysed parasite densities using generalised estimating equations. This study is registered with ClinicalTrials.gov, number NCT00669084. FINDINGS Between May 1, 2008, and Dec 29, 2011, we enrolled 1586 children into the study. We successfully typed all five red blood cell variants for 1543 of these children, who therefore constituted the evaluable population and in whom we diagnosed 4091 malaria episodes over 2656 child-years of follow-up. In these 1543 children, red blood cell variants were common, and occurred at the following frequencies: sickle cell trait (HbAS) 220 (14%), HbC heterozygosity (HbAC) 103 (7%), α thalassaemia 438 (28%), type O blood group 621 (40%), and G6PD deficiency 72 (9%) in 767 boys and 158 (20%) in 776 girls. The overall incidence of malaria was 1.54 episodes per child-year of follow-up, ranging from 2.78 episodes per child-year at age 3 years to 0.40 episodes per child-year at age 17 years. The malaria incidence was lower in HbAS children than in HbAA children with normal haemoglobin (adjusted incidence rate ratio [aIRR] 0.66 [95% CI 0.59-0.75], p<0.0001) and lower in G6PD A-/A- homozygous girls than in G6PD A+/A+ girls (0.51 [0.29-0.90], p=0.020), but was higher in HbAC children than in HbAA children (1.15 [1.01-1.32], p=0.039). Parasite density was lower in HbAS children (median 10,550 parasites per μL [IQR 1350-26,250]) than in HbAA children (15,150 parasites per μL [4250-31,050]; p=0.0004). The HbAS-associated reductions in malaria risk and parasite density were greatest in early childhood. INTERPRETATION The individual and interactive effects of HbAS, HbAC, and G6PD A-/A- genotypes on malaria risk and parasite density define clinical and cellular correlates of protection. Further identification of the molecular mechanisms of these protective effects might uncover new targets for intervention. FUNDING Intramural Research Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health.
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Affiliation(s)
- Tatiana M Lopera-Mesa
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Saibou Doumbia
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Drissa Konaté
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Jennifer M Anderson
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mory Doumbouya
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Abdoul S Keita
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | | | - Karim Traoré
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Michael A Krause
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Samuel E Moretz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Gregory S Tullo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Wenjuan Gu
- Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research Inc, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Michael P Fay
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Steve M Taylor
- Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, NC, USA; Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mahamadou Diakité
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
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Impact of malaria preexposure on antiparasite cellular and humoral immune responses after controlled human malaria infection. Infect Immun 2015; 83:2185-96. [PMID: 25776749 DOI: 10.1128/iai.03069-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/09/2015] [Indexed: 11/20/2022] Open
Abstract
To understand the effect of previous malaria exposure on antiparasite immune responses is important for developing successful immunization strategies. Controlled human malaria infections (CHMIs) using cryopreserved Plasmodium falciparum sporozoites provide a unique opportunity to study differences in acquisition or recall of antimalaria immune responses in individuals from different transmission settings and genetic backgrounds. In this study, we compared antiparasite humoral and cellular immune responses in two cohorts of malaria-naive Dutch volunteers and Tanzanians from an area of low malarial endemicity, who were subjected to the identical CHMI protocol by intradermal injection of P. falciparum sporozoites. Samples from both trials were analyzed in parallel in a single center to ensure direct comparability of immunological outcomes. Within the Tanzanian cohort, we distinguished one group with moderate levels of preexisting antibodies to asexual P. falciparum lysate and another that, based on P. falciparum serology, resembled the malaria-naive Dutch cohort. Positive P. falciparum serology at baseline was associated with a lower parasite density at first detection by quantitative PCR (qPCR) after CHMI than that for Tanzanian volunteers with negative serology. Post-CHMI, both Tanzanian groups showed a stronger increase in anti-P. falciparum antibody titers than Dutch volunteers, indicating similar levels of B-cell memory independent of serology. In contrast to the Dutch, Tanzanians failed to increase P. falciparum-specific in vitro recall gamma interferon (IFN-γ) production after CHMI, and innate IFN-γ responses were lower in P. falciparum lysate-seropositive individuals than in seronegative individuals. In conclusion, positive P. falciparum lysate serology can be used to identify individuals with better parasite control but weaker IFN-γ responses in circulating lymphocytes, which may help to stratify volunteers in future CHMI trials in areas where malaria is endemic.
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Mangano VD, Kabore Y, Bougouma EC, Verra F, Sepulveda N, Bisseye C, Santolamazza F, Avellino P, Tiono AB, Diarra A, Nebie I, Rockett KA, Sirima SB, Modiano D. Novel Insights Into the Protective Role of Hemoglobin S and C Against Plasmodium falciparum Parasitemia. J Infect Dis 2015; 212:626-34. [PMID: 25712976 PMCID: PMC4512610 DOI: 10.1093/infdis/jiv098] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/13/2015] [Indexed: 02/04/2023] Open
Abstract
Although hemoglobin S (HbS) and hemoglobin C (HbC) are well known to protect against severe Plasmodium falciparum malaria, conclusive evidence on their role against infection has not yet been obtained. Here we show, in 2 populations from Burkina Faso (2007-2008), that HbS is associated with a 70% reduction of harboring P. falciparum parasitemia at the heterozygous state (odds ratio [OR] for AS vs AA, 0.27; 95% confidence interval [CI], .11-.66; P = .004). There is no evidence of protection for HbC in the heterozygous state (OR for AC vs AA, 1.49; 95% CI, .69-3.21; P = .31), whereas protection even higher than that observed with AS is observed in the homozygous and double heterozygous states (OR for CC + SC vs AA, 0.04; 95% CI, .01-.29; P = .002). The abnormal display of parasite-adhesive molecules on the surface of HbS and HbC infected erythrocytes, disrupting the pathogenic process of sequestration, might displace the parasite from the deep to the peripheral circulation, promoting its elimination at the spleen level.
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Affiliation(s)
- Valentina D Mangano
- Department of Public Health and Infectious Diseases Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy
| | - Youssouf Kabore
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Edith C Bougouma
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - Nuno Sepulveda
- London School of Hygiene and Tropical Medicine Center of Statistics and Applications of University of Lisbon, Portugal
| | - Cyrille Bisseye
- Department of Public Health and Infectious Diseases Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | | | - Alfred B Tiono
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Amidou Diarra
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issa Nebie
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Kirk A Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Sodiomon B Sirima
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - David Modiano
- Department of Public Health and Infectious Diseases Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy
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Grant CR, Liberal R, Mieli-Vergani G, Vergani D, Longhi MS. Regulatory T-cells in autoimmune diseases: challenges, controversies and--yet--unanswered questions. Autoimmun Rev 2014; 14:105-16. [PMID: 25449680 DOI: 10.1016/j.autrev.2014.10.012] [Citation(s) in RCA: 202] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 09/26/2014] [Indexed: 02/07/2023]
Abstract
Regulatory T cells (Tregs) are central to the maintenance of self-tolerance and tissue homeostasis. Markers commonly used to define human Tregs in the research setting include high expression of CD25, FOXP3 positivity and low expression/negativity for CD127. Many other markers have been proposed, but none unequivocally identifies bona fide Tregs. Tregs are equipped with an array of mechanisms of suppression, including the modulation of antigen presenting cell maturation and function, the killing of target cells, the disruption of metabolic pathways and the production of anti-inflammatory cytokines. Treg impairment has been reported in a number of human autoimmune conditions and includes Treg numerical and functional defects and conversion into effector cells in response to inflammation. In addition to intrinsic Treg impairment, resistance of effector T cells to Treg control has been described. Discrepancies in the literature are common, reflecting differences in the choice of study participants and the technical challenges associated with investigating this cell population. Studies differ in terms of the methodology used to define and isolate putative regulatory cells and to assess their suppressive function. In this review we outline studies describing Treg frequency and suppressive function in systemic and organ specific autoimmune diseases, with a specific focus on the challenges faced when investigating Tregs in these conditions.
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Affiliation(s)
- Charlotte R Grant
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King's College London, London, United Kingdom; Faculty of Life Sciences and Medicine, King's College Hospital, London, United Kingdom.
| | - Rodrigo Liberal
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King's College London, London, United Kingdom; Faculty of Life Sciences and Medicine, King's College Hospital, London, United Kingdom.
| | - Giorgina Mieli-Vergani
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King's College London, London, United Kingdom; Faculty of Life Sciences and Medicine, King's College Hospital, London, United Kingdom.
| | - Diego Vergani
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King's College London, London, United Kingdom; Faculty of Life Sciences and Medicine, King's College Hospital, London, United Kingdom.
| | - Maria Serena Longhi
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King's College London, London, United Kingdom; Faculty of Life Sciences and Medicine, King's College Hospital, London, United Kingdom.
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van den Bogaart E, Talha ABA, Straetemans M, Mens PF, Adams ER, Grobusch MP, Nour BYM, Schallig HDFH. Cytokine profiles amongst Sudanese patients with visceral leishmaniasis and malaria co-infections. BMC Immunol 2014; 15:16. [PMID: 24886212 PMCID: PMC4024313 DOI: 10.1186/1471-2172-15-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/16/2014] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The immune system plays a critical role in the development of co-infections, promoting or preventing establishment of multiple infections and shaping the outcome of pathogen-host interactions. Its ability to mediate the interplay between visceral leishmaniasis (VL) and malaria has been suggested, but poorly documented. The present study investigated whether concomitant infection with Leishmania donovani complex and Plasmodium falciparum in naturally co-infected patients altered the immunological response elicited by the two pathogens individually. RESULTS Circulating levels of interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12p70, IL-13, IL-17A and tumor necrosis factor (TNF) were assessed in sera of patients infected with active VL and/or malaria and healthy individuals from Gedarif State, Sudan. Comparative analysis of cytokine profiles from co- and mono-infected patients highlighted significant differences in the immune response mounted upon co-infection, confirming the ability of L. donovani and P. falciparum to mutually interact at the immunological level. Progressive polarization towards type-1 and pro-inflammatory cytokine patterns characterized the co-infected patients, whose response partly reflected the effect elicited by VL (IFN-γ, TNF) and malaria (IL-2, IL-13), and partly resulted from a synergistic interaction of the two diseases upon each other (IL-17A). Significantly reduced levels of P. falciparum parasitaemia (P <0.01) were detected in the co-infected group as opposed to the malaria-only patients, suggesting either a protective or a non-detrimental effect of the co-infection against P. falciparum infection. CONCLUSIONS These findings suggest that a new immunological scenario may occur when L. donovani and P. falciparum co-infect the same patient, with potential implications on the course and resolution of these diseases.
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Affiliation(s)
- Erika van den Bogaart
- Department of Biomedical Research, Royal Tropical Institute (KIT), Amsterdam, The Netherlands.
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Rizzo C, Ronca R, Lombardo F, Mangano V, Sirima SB, Nèbiè I, Fiorentino G, Troye-Blomberg M, Modiano D, Arcà B. IgG1 and IgG4 antibody responses to the Anopheles gambiae salivary protein gSG6 in the sympatric ethnic groups Mossi and Fulani in a malaria hyperhendemic area of Burkina Faso. PLoS One 2014; 9:e96130. [PMID: 24760038 PMCID: PMC3997568 DOI: 10.1371/journal.pone.0096130] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/02/2014] [Indexed: 12/16/2022] Open
Abstract
Human antibody response to the Anopheles gambiae salivary protein gSG6 has recently emerged as a potentially useful tool for malaria epidemiological studies and for the evaluation of vector control interventions. However, the current understanding of the host immune response to mosquito salivary proteins and of the possible crosstalk with early response to Plasmodium parasites is still very limited. We report here the analysis of IgG1 and IgG4 subclasses among anti-gSG6 IgG responders belonging to Mossi and Fulani from Burkina Faso, two ethnic groups which are known for their differential humoral response to parasite antigens and for their different susceptibility to malaria. The IgG1 antibody response against the gSG6 protein was comparable in the two groups. On the contrary, IgG4 titers were significantly higher in the Fulani where, in addition, anti-gSG6 IgG4 antibodies appeared in younger children and the ratio IgG4/IgG1 stayed relatively stable throughout adulthood. Both gSG6-specific IgG1 and IgG4 antibodies showed a tendency to decrease with age whereas, as expected, the IgG response to the Plasmodium circumsporozoite protein (CSP) exhibited an opposite trend in the same individuals. These observations are in line with the idea that the An. gambiae gSG6 salivary protein induces immune tolerance, especially after intense and prolonged exposure as is the case for the area under study, suggesting that gSG6 may trigger in exposed individuals a Th2-oriented immune response.
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Affiliation(s)
- Cinzia Rizzo
- Department of Public Health and Infectious Diseases - Parasitology Section, “Sapienza” University, Rome, Italy
| | - Raffaele Ronca
- Department of Biology, “Federico II” University, Naples, Italy
| | - Fabrizio Lombardo
- Department of Public Health and Infectious Diseases - Parasitology Section, “Sapienza” University, Rome, Italy
| | - Valentina Mangano
- Department of Public Health and Infectious Diseases - Parasitology Section, “Sapienza” University, Rome, Italy
| | | | - Issa Nèbiè
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - Marita Troye-Blomberg
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - David Modiano
- Department of Public Health and Infectious Diseases - Parasitology Section, “Sapienza” University, Rome, Italy
- Istituto Pasteur Fondazione Cenci-Bolognetti, Sapienza University, Rome, Italy
| | - Bruno Arcà
- Department of Public Health and Infectious Diseases - Parasitology Section, “Sapienza” University, Rome, Italy
- Department of Biology, “Federico II” University, Naples, Italy
- * E-mail:
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Torres KJ, Villasis E, Bendezú J, Chauca J, Vinetz JM, Gamboa D. Relationship of regulatory T cells to Plasmodium falciparum malaria symptomatology in a hypoendemic region. Malar J 2014; 13:108. [PMID: 24642188 PMCID: PMC3976150 DOI: 10.1186/1475-2875-13-108] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 03/14/2014] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Previous data have suggested that regulatory T cells (Tregs) balance protective immune responses with immune mediated pathology in malaria. This study aimed to determine to test the hypothesis that Treg proportions or absolute levels are associated with parasitaemia and malaria symptoms. METHODS Treg cells were quantified by flow cytometry as CD4+ CD25+, Foxp3+, CD127(low) T cells. Three patient groups were assessed: patients with symptomatic Plasmodium falciparum malaria (S), subjects with asymptomatic P. falciparum parasitaemia (AS) and uninfected control individuals (C). RESULTS S, AS and C groups had similar absolute numbers and percentage of Tregs (3.9%, 3.5% and 3.5% respectively). Levels of parasitaemia were not associated with Treg percentage (p = 0.47). CONCLUSION Neither relative nor absolute regulatory T cell numbers were found to be associated with malaria-related symptomatology in this study. Immune mechanisms other than Tregs are likely to be responsible for the state of asymptomatic P. falciparum parasitaemia in the Peruvian Amazon; but further study to explore these mechanisms is needed.
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Affiliation(s)
| | | | | | | | - Joseph M Vinetz
- Instituto de Medicina Tropical "Alexander Von Humboldt", Universidad Peruana, Cayetano Heredia, AP 4314, Lima 100, Peru.
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Azcárate IG, Marín-García P, Kamali AN, Pérez-Benavente S, Puyet A, Diez A, Bautista JM. Differential immune response associated to malaria outcome is detectable in peripheral blood following Plasmodium yoelii infection in mice. PLoS One 2014; 9:e85664. [PMID: 24465641 PMCID: PMC3900426 DOI: 10.1371/journal.pone.0085664] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 12/01/2013] [Indexed: 11/18/2022] Open
Abstract
Malaria infection in humans elicits a wide range of immune responses that can be detected in peripheral blood, but we lack detailed long-term follow-up data on the primary and subsequent infections that lead to naturally acquired immunity. Studies on antimalarial immune responses in mice have been based on models yielding homogenous infection profiles. Here, we present a mouse model in which a heterogeneous course of Plasmodium yoelii lethal malaria infection is produced in a non-congenic ICR strain to allow comparison among different immunological and clinical outcomes. Three different disease courses were observed ranging from a fatal outcome, either early or late, to a self-resolved infection that conferred long-term immunity against re-infection. Qualitative and quantitative changes produced in leukocyte subpopulations and cytokine profiles detected in peripheral blood during the first week of infection revealed that monocytes, dendritic cells and immature B cells were the main cell subsets present in highly-parasitized mice dying in the first week after infection. Besides, CD4(+)CD25(high) T cells expanded at an earlier time point in early deceased mice than in surviving mice and expressed higher levels of intracellular Foxp3 protein. In contrast, survivors showed a limited increase of cytokines release and stable circulating innate cells. From the second week of infection, mice that would die or survive showed similar immune profiles, although CD4(+)CD25(high) T cells number increased earlier in mice with the worst prognosis. In surviving mice the expansion of activated circulating T cell and switched-class B cells with a long-term protective humoral response from the second infection week is remarkable. Our results demonstrate that the follow-up studies of immunological blood parameters during a malaria infection can offer information about the course of the pathological process and the immune response.
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Affiliation(s)
- Isabel G. Azcárate
- Department of Biochemistry and Molecular Biology IV, Universidad Complutense de Madrid, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain
- Research Institute Hospital 12 de Octubre, University Hospital 12 de Octubre, Madrid, Spain,
| | - Patricia Marín-García
- Department of Biochemistry and Molecular Biology IV, Universidad Complutense de Madrid, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain
| | - Alí N. Kamali
- Department of Biochemistry and Molecular Biology IV, Universidad Complutense de Madrid, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain
| | - Susana Pérez-Benavente
- Department of Biochemistry and Molecular Biology IV, Universidad Complutense de Madrid, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain
| | - Antonio Puyet
- Department of Biochemistry and Molecular Biology IV, Universidad Complutense de Madrid, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain
- Research Institute Hospital 12 de Octubre, University Hospital 12 de Octubre, Madrid, Spain,
| | - Amalia Diez
- Department of Biochemistry and Molecular Biology IV, Universidad Complutense de Madrid, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain
- Research Institute Hospital 12 de Octubre, University Hospital 12 de Octubre, Madrid, Spain,
| | - José M. Bautista
- Department of Biochemistry and Molecular Biology IV, Universidad Complutense de Madrid, Facultad de Veterinaria, Ciudad Universitaria, Madrid, Spain
- Research Institute Hospital 12 de Octubre, University Hospital 12 de Octubre, Madrid, Spain,
- * E-mail:
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Tiono AB, Sirima SB, Hamed K. Fulani show decreased susceptibility to Plasmodium falciparum infection versus Mossi: data from a community-wide screening and treatment of asymptomatic carriers in Burkina Faso. Malar J 2013; 12:163. [PMID: 23680454 PMCID: PMC3662604 DOI: 10.1186/1475-2875-12-163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 05/14/2013] [Indexed: 11/10/2022] Open
Abstract
Background The Fulani ethnic group is known to have a lower susceptibility to Plasmodium falciparum infection than the Mossi. Methods This commentary describes data from a recent cluster-randomized trial of community-wide screening and treatment of asymptomatic carriers of P. falciparum in 18 villages in Saponé, Burkina Faso. Results The Fulani groups had a lower proportion of asymptomatic carriers at any occasion, a lower density of asexual forms and gametocytes of P. falciparum at baseline, and, in children under five years of age, lower rates of symptomatic malaria episodes per person-year than the Mossi. Discussion and conclusion These data confirm previously reported differences in P. falciparum susceptibility between Fulani and Mossi.
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Genovese L, Nebuloni M, Alfano M. Cell-Mediated Immunity in Elite Controllers Naturally Controlling HIV Viral Load. Front Immunol 2013; 4:86. [PMID: 23577012 PMCID: PMC3620550 DOI: 10.3389/fimmu.2013.00086] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 03/26/2013] [Indexed: 12/26/2022] Open
Abstract
The natural course of human immunodeficiency virus (HIV) infection is characterized by high viral load, depletion of immune cells, and immunodeficiency, ultimately leading to acquired immunodeficiency syndrome phase and the occurrence of opportunistic infections and diseases. Since the discovery of HIV in the early 1980s a naturally selected population of infected individuals has been emerged in the last years, characterized by being infected for many years, with viremia constantly below detectable level and poor depletion of immune cells. These individuals are classified as “elite controllers (EC) or suppressors” and do not develop disease in the absence of anti-retroviral therapy. Unveiling host factors and immune responses responsible for the elite status will likely provide clues for the design of therapeutic vaccines and functional cures. Scope of this review was to examine and discuss differences of the cell-mediated immune responses between HIV+ individuals with disease progression and EC.
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Affiliation(s)
- Luca Genovese
- AIDS Immunopathogenesis Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute Milan, Italy
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44
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The frequency of an IL-18-associated haplotype in Africans. Eur J Hum Genet 2013; 21:465-8. [DOI: 10.1038/ejhg.2012.184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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45
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Modulation of the immune and inflammatory responses by Plasmodium falciparum schizont extracts: role of myeloid dendritic cells in effector and regulatory functions of CD4+ lymphocytes. Infect Immun 2013; 81:1842-51. [PMID: 23509139 DOI: 10.1128/iai.01226-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The optimal immune response to malaria infection comprises rapid induction of inflammatory responses promptly counteracted by regulatory mechanisms to prevent immunopathology. To evaluate the role of dendritic cells (DC) in the balance of parasite-induced inflammatory/anti-inflammatory mechanisms, we studied the activity of monocyte-derived dendritic cells (MDDC), previously exposed to soluble extracts of Plasmodium falciparum-infected red blood cells (PfSE), in the differentiation of CD4 cells isolated from donors never exposed to malaria infection. We show that MDDC exposed to PfSE are extremely efficient to induce a contemporary differentiation of TH1 effector cells and T regulatory (Treg) cells in CD4 T cells even when exposed to low concentrations of parasitic extracts. Treg cells induced by MDDC infected with PfSE (MDDC-PfSE) produce transforming growth factor beta (TGF-β) and interleukin 10 (IL-10) and are endowed with strong suppressive properties. They also show phenotypical and functional peculiarities, such as the contemporary expression of markers of Treg and TH1 differentiation and higher sensitivity to TLR4 ligands both inducing an increasing production of suppressive cytokines. On the whole, our data indicate that MDDC exposed to PfSE orchestrate a well-balanced immune response with timely differentiation of TH1 and Treg cells in CD4 cells from nonimmune donors and suggest that, during the infection, the role of MDCC could be particularly relevant in low-parasitemia conditions.
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46
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Wammes LJ, Wiria AE, Toenhake CG, Hamid F, Liu KY, Suryani H, Kaisar MMM, Verweij JJ, Sartono E, Supali T, Smits HH, Luty AJ, Yazdanbakhsh M. Asymptomatic plasmodial infection is associated with increased tumor necrosis factor receptor II-expressing regulatory T cells and suppressed type 2 immune responses. J Infect Dis 2013; 207:1590-9. [PMID: 23408847 DOI: 10.1093/infdis/jit058] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND In malaria-endemic areas, a proportion of individuals becomes chronic carriers of parasites with few or no clinical signs. There is little information on cellular immune responses in asymptomatic parasite carriers. METHODS In 80 schoolchildren residing in a malaria-endemic area of Flores Island, Indonesia, T-helper subsets, regulatory T-cell (Treg) frequencies, tumor necrosis factor receptor type II (TNFRII) expression on Tregs, and cytokine responses induced by Plasmodium falciparum-infected red blood cells (RBCs) were measured, and values for asymptomatic infected subjects were compared to those for uninfected controls. To ascertain that alterations found were due to the presence of malaria parasites, the immune responses were analyzed in 16 children before and 1 month after antimalarial treatment. RESULTS TNFRII expression, a marker of activation on Tregs, was higher during infection but decreased upon treatment. GATA3-positive cells and the level of interleukin 13 secretion in response to P. falciparum-infected RBCs appeared to be suppressed by plasmodial infection, as both increased after antimalarial treatment. TNFRII expression on Tregs correlated positively with TNF in response to P. falciparum-infected RBCs, but this association disappeared following treatment. CONCLUSIONS Malaria parasites associated with asymptomatic infections seem to result in increased TNFRII expression on Tregs, as well as suppressed Th2 cytokine responses, features that might be important for survival of the parasites in asymptomatic carriers.
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Affiliation(s)
- Linda J Wammes
- Department of Parasitology, Leiden University Medical Center, the Netherlands
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Evidence for additive and interaction effects of host genotype and infection in malaria. Proc Natl Acad Sci U S A 2012; 109:16786-93. [PMID: 22949651 DOI: 10.1073/pnas.1204945109] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The host mechanisms responsible for protection against malaria remain poorly understood, with only a few protective genetic effects mapped in humans. Here, we characterize a host-specific genome-wide signature in whole-blood transcriptomes of Plasmodium falciparum-infected West African children and report a demonstration of genotype-by-infection interactions in vivo. Several associations involve transcripts sensitive to infection and implicate complement system, antigen processing and presentation, and T-cell activation (i.e., SLC39A8, C3AR1, FCGR3B, RAD21, RETN, LRRC25, SLC3A2, and TAPBP), including one association that validated a genome-wide association candidate gene (SCO1), implicating binding variation within a noncoding regulatory element. Gene expression profiles in mice infected with Plasmodium chabaudi revealed and validated similar responses and highlighted specific pathways and genes that are likely important responders in both hosts. These results suggest that host variation and its interplay with infection affect children's ability to cope with infection and suggest a polygenic model mounted at the transcriptional level for susceptibility.
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Carli C, Giroux M, Delisle JS. Roles of Transforming Growth Factor-β in Graft-versus-Host and Graft-versus-Tumor Effects. Biol Blood Marrow Transplant 2012; 18:1329-40. [DOI: 10.1016/j.bbmt.2012.01.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 01/27/2012] [Indexed: 01/07/2023]
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Rowe JH, Ertelt JM, Way SS. Foxp3(+) regulatory T cells, immune stimulation and host defence against infection. Immunology 2012; 136:1-10. [PMID: 22211994 PMCID: PMC3372751 DOI: 10.1111/j.1365-2567.2011.03551.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The immune system is intricately regulated allowing potent effectors to expand and become rapidly mobilized after infection, while simultaneously silencing potentially detrimental responses that averts immune-mediated damage to host tissues. This relies in large part on the delicate interplay between immune suppressive regulatory CD4+ T (Treg) cells and immune effectors that without active suppression by Treg cells cause systemic and organ-specific autoimmunity. Although these beneficial roles have been classically described as counterbalanced by impaired host defence against infection, newfound protective roles for Treg cells against specific viral pathogens (e.g. herpes simplex virus 2, lymphocytic choriomeningitis virus, West Nile virus) have been uncovered using transgenic mice that allow in vivo Treg-cell ablation based on Foxp3 expression. In turn, Foxp3+ Treg cells also provide protection against some parasitic (Plasmodium sp., Toxoplasma gondii) and fungal (Candida albicans) pathogens. By contrast, for bacterial and mycobacterial infections (e.g. Listeria monocytogenes, Salmonella enterica, Mycobacterium tuberculosis), experimental manipulation of Foxp3+ cells continues to indicate detrimental roles for Treg cells in host defence. This variance is probably related to functional plasticity in Treg cell suppression that shifts discordantly following infection with different types of pathogens. Furthermore, the efficiency whereby Treg cells silence immune activation coupled with the plasticity in Foxp3+ cell activity suggest that overriding Treg-mediated suppression represents a prerequisite ‘signal zero’ that together with other stimulation signals [T-cell receptor (signal 1), co-stimulation (signal 2), inflammatory cytokines (signal 3)] are essential for T-cell activation in vivo. Herein, the importance of Foxp3+ Treg cells in host defence against infection, and the significance of infection-induced shifts in Treg-cell suppression are summarized.
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Affiliation(s)
- Jared H Rowe
- Departments of Pediatrics and Microbiology, University of Minnesota School of Medicine, Center for Infectious Disease and Microbiology Translational Research, Minneapolis, MN 55455, USA
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Abel S, Lückheide N, Westendorf AM, Geffers R, Roers A, Müller W, Sparwasser T, Matuschewski K, Buer J, Hansen W. Strong impact of CD4+ Foxp3+ regulatory T cells and limited effect of T cell-derived IL-10 on pathogen clearance during Plasmodium yoelii infection. THE JOURNAL OF IMMUNOLOGY 2012; 188:5467-77. [PMID: 22544931 DOI: 10.4049/jimmunol.1102223] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is well established that CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) play a crucial role in the course of different infectious diseases. However, contradictory results have been published regarding to malaria infection. In this study, we report that specific ablation of Foxp3(+) Tregs in Plasmodium yoelii-infected DEREG-BALB/c mice leads to an increase in T cell activation accompanied by a significant decrease in parasitemia. To better understand how Foxp3(+) Tregs orchestrate this phenotype, we used microarrays to analyze CD4(+)CD25(+)Foxp3(+) Tregs and CD4(+)CD25(-)Foxp3(-) T cells in the course of P. yoelii infection. Using this approach we identified genes specifically upregulated in CD4(+)CD25(+)Foxp3(+) Tregs in the course of infection, such as G-protein-coupled receptor 83 and Socs2. This analysis also revealed that both CD4(+)CD25(+)Foxp3(+) Tregs and CD4(+)CD25(-)Foxp3(-) T cells upregulate CTLA-4, granzyme B, and, more strikingly, IL-10 during acute blood infection. Therefore, we aimed to define the function of T cell-derived IL-10 in this context by Cre/loxP-mediated selective conditional inactivation of the IL-10 gene in T cells. Unexpectedly, IL-10 ablation in T cells exerts only a minor effect on parasite clearance, even though CD8(+) T cells are more strongly activated, the production of IFN-γ and TNF-α by CD4(+)CD25(-) T cells is increased, and the suppressive activity of CD4(+)CD25(+) Tregs is reduced upon infection. In summary, these results suggest that CD4(+)Foxp3(+) Tregs modulate the course of P. yoelii infection in BALB/c mice. Moreover, CD4(+) T cell-derived IL-10 affects T effector function and Treg activity, but has only a limited direct effect on parasite clearance in this model.
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Affiliation(s)
- Simone Abel
- Institute of Medical Microbiology, University Hospital Essen, University Duisburg-Essen, 45122 Essen, Germany
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