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Morter R, Tiono AB, Nébié I, Hague O, Ouedraogo A, Diarra A, Viebig NK, Hill AVS, Ewer KJ, Sirima SB. Impact of exposure to malaria and nutritional status on responses to the experimental malaria vaccine ChAd63 MVA ME-TRAP in 5-17 month-old children in Burkina Faso. Front Immunol 2022; 13:1058227. [PMID: 36532031 PMCID: PMC9755991 DOI: 10.3389/fimmu.2022.1058227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/17/2022] [Indexed: 12/05/2022] Open
Abstract
The experimental malaria vaccine ChAd63 MVA ME-TRAP previously showed protective efficacy against Plasmodium falciparum infection in Phase IIa sporozoite challenge studies in adults in the United Kingdom and in a Phase IIb field efficacy trial in Kenyan adults. However, it failed to demonstrate efficacy in a phase IIb trial in 5-17 month-old children in an area of high malaria transmission in Burkina Faso. This secondary analysis investigated whether exposure to malaria or nutritional status might be associated with reduced responses to vaccination in this cohort. Parasite blood smears and anti-AMA-1 IgG titres were used to assess history of exposure to malaria and weight-for-length Z scores were calculated to assess nutritional status. Differences in vaccine-specific anti-TRAP IgG titre and ex vivo IFNγ ELISpot response were measured between groups. In total, n = 336 volunteers randomised to receive the experimental vaccine regimen were included in this analysis. A positive smear microscopy result was associated with reduced anti-TRAP IgG titre (geometric mean titre: 2775 (uninfected) vs 1968 (infected), p = 0.025), whilst anti-AMA-1 IgG titres were weakly negatively correlated with reduced ex vivo IFNγ ELISpot response (r = -0.18, p = 0.008). Nutritional status was not associated with either humoral or cellular immunogenicity. Vaccine efficacy was also measured separately for vaccinees with positive and negative blood smears. Although not significant in either group compared to controls, vaccine efficacy measured by Cox hazard ratio was higher in uninfected compared to infected individuals (19.8% [p = 0.50] vs 3.3% [p = 0.69]). Overall, this data suggests exposure to malaria may be associated with impaired vaccine immunogenicity. This may have consequences for the testing and eventual deployment of various vaccines, in areas with high endemicity for malaria. Trial Registration Pactr.org, identifier PACTR201208000404131; ClinicalTrials.gov, identifier NCT01635647.
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Affiliation(s)
- Richard Morter
- Nuffield Department of Clinical Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Alfred B. Tiono
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso,Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Issa Nébié
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Oliver Hague
- Nuffield Department of Clinical Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Amidou Diarra
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Nicola K. Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Heidelberg, Germany
| | - Adrian V. S. Hill
- Nuffield Department of Clinical Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Katie J. Ewer
- Nuffield Department of Clinical Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom,*Correspondence: Sodiomon B. Sirima, ; Katie J. Ewer,
| | - Sodiomon B. Sirima
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso,*Correspondence: Sodiomon B. Sirima, ; Katie J. Ewer,
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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: 12] [Impact Index Per Article: 4.0] [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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Wahab A, Shaukat A, Ali Q, Hussain M, Khan TA, Khan MAU, Rashid I, Saleem MA, Evans M, Sargison ND, Chaudhry U. A novel metabarcoded 18S ribosomal DNA sequencing tool for the detection of Plasmodium species in malaria positive patients. INFECTION GENETICS AND EVOLUTION 2020; 82:104305. [PMID: 32247865 DOI: 10.1016/j.meegid.2020.104305] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/13/2020] [Accepted: 03/26/2020] [Indexed: 02/07/2023]
Abstract
Various PCR based methods have been described for the diagnosis of malaria, but most depend on the use of Plasmodium species-specific probes and primers; hence only the tested species are identified and there is limited available data on the true circulating species diversity. Sensitive diagnostic tools and platforms for their use are needed to detect Plasmodium species in both clinical cases and asymptomatic infections that contribute to disease transmission. We have recently developed for the first time a novel high throughput 'haemoprotobiome' metabarcoded DNA sequencing method and applied it for the quantification of haemoprotozoan parasites (Theleria and Babesia) of livestock. Here, we describe a novel, high throughput method using an Illumina MiSeq platform to demonstrate the proportions of Plasmodium species in metabarcoded DNA samples derived from human malaria patients. Plasmodium falciparum and Plasmodium vivax positive control gDNA was used to prepare mock DNA pools of parasites to evaluate the detection threshold of the assay for each of the two species. The different mock pools demonstrate the accurate detection ability and to show the proportions of each of the species being present. We then applied the assay to malaria-positive human samples to show the species composition of Plasmodium communities in the Punjab province of Pakistan and in the Afghanistan-Pakistan tribal areas. The diagnostic performance of the deep amplicon sequencing method was compared to an immunochromatographic assay that is widely used in the region. The deep amplicon sequencing showed that P. vivax was present in 69.8%, P. falciparum in 29.5% and mixed infection in 0.7% patients examined. The immunochromatographic assay showed that P. vivax was present in 65.6%, P. falciparum in 27.4%, mixed infection 0.7% patients and 6.32% malaria-positive cases were negative in immunochromatographic assay, but positive in the deep amplicon sequencing. Overall, metabarcoded DNA sequencing demonstrates better diagnostic performance, greatly increasing the estimated prevalence of Plasmodium infection. The next-generation sequencing method using metabarcoded DNA has potential applications in the diagnosis, surveillance, treatment, and control of Plasmodium infections, as well as to study the parasite biology.
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Affiliation(s)
- Abdul Wahab
- University of Science and Technology, Kohat, Khyber Pakhtunkhwa, Pakistan
| | - Ayaz Shaukat
- University of Central Punjab, Lahore, Punjab, Pakistan
| | - Qasim Ali
- Gomal University, Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan
| | - Mubashir Hussain
- University of Science and Technology, Kohat, Khyber Pakhtunkhwa, Pakistan
| | - Taj Ali Khan
- University of Science and Technology, Kohat, Khyber Pakhtunkhwa, Pakistan
| | | | - Imran Rashid
- University of Veterinary and Animal Sciences, Lahore, Punjab, Pakistan
| | | | - Mike Evans
- Royal Dick School of Veterinary Studies, University of Edinburgh, UK
| | - Neil D Sargison
- Royal Dick School of Veterinary Studies, University of Edinburgh, UK.
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Penha-Gonçalves C. Genetics of Malaria Inflammatory Responses: A Pathogenesis Perspective. Front Immunol 2019; 10:1771. [PMID: 31417551 PMCID: PMC6682681 DOI: 10.3389/fimmu.2019.01771] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 07/15/2019] [Indexed: 12/27/2022] Open
Abstract
Despite significant progress in combating malaria in recent years the burden of severe disease and death due to Plasmodium infections remains a global public health concern. Only a fraction of infected people develops severe clinical syndromes motivating a longstanding search for genetic determinants of malaria severity. Strong genetic effects have been repeatedly ascribed to mutations and allelic variants of proteins expressed in red blood cells but the role of inflammatory response genes in disease pathogenesis has been difficult to discern. We revisited genetic evidence provided by inflammatory response genes that have been repeatedly associated to malaria, namely TNF, NOS2, IFNAR1, HMOX1, TLRs, CD36, and CD40LG. This highlighted specific genetic variants having opposing roles in the development of distinct malaria clinical outcomes and unveiled diverse levels of genetic heterogeneity that shaped the complex association landscape of inflammatory response genes with malaria. However, scrutinizing genetic effects of individual variants corroborates a pathogenesis model where pro-inflammatory genetic variants acting in early infection stages contribute to resolve infection but at later stages confer increased vulnerability to severe organ dysfunction driven by tissue inflammation. Human genetics studies are an invaluable tool to find genes and molecular pathways involved in the inflammatory response to malaria but their precise roles in disease pathogenesis are still unexploited. Genome editing in malaria experimental models and novel genotyping-by-sequencing techniques are promising approaches to delineate the relevance of inflammatory response gene variants in the natural history of infection thereby will offer new rational angles on adjuvant therapeutics for prevention and clinical management of severe malaria.
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Decrease in circulating CD25 hi Foxp3 + regulatory T cells following vaccination with the candidate malaria vaccine RTS,S. Vaccine 2016; 34:4618-4625. [DOI: 10.1016/j.vaccine.2016.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 06/20/2016] [Accepted: 07/06/2016] [Indexed: 11/23/2022]
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Carvalho TG, Morahan B, John von Freyend S, Boeuf P, Grau G, Garcia-Bustos J, Doerig C. The ins and outs of phosphosignalling in Plasmodium: Parasite regulation and host cell manipulation. Mol Biochem Parasitol 2016; 208:2-15. [PMID: 27211241 DOI: 10.1016/j.molbiopara.2016.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 05/16/2016] [Indexed: 12/15/2022]
Abstract
Signal transduction and kinomics have been rapidly expanding areas of investigation within the malaria research field. Here, we provide an overview of phosphosignalling pathways that operate in all stages of the Plasmodium life cycle. We review signalling pathways in the parasite itself, in the cells it invades, and in other cells of the vertebrate host with which it interacts. We also discuss the potential of these pathways as novel targets for antimalarial intervention.
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Affiliation(s)
- Teresa Gil Carvalho
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Belinda Morahan
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Simona John von Freyend
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Philippe Boeuf
- Burnet Institute, Melbourne, Victoria 3004, Australia; The University of Melbourne, Department of Medicine, Melbourne, Victoria 3010, Australia; Victorian Infectious Diseases Service, Royal Melbourne Hospital, Melbourne, Victoria 3010, Australia
| | - Georges Grau
- Vascular Immunology Unit, Department of Pathology, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia
| | - Jose Garcia-Bustos
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Christian Doerig
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia.
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Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
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Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
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Li S, Plebanski M, Smooker P, Gowans EJ. Editorial: Why Vaccines to HIV, HCV, and Malaria Have So Far Failed-Challenges to Developing Vaccines Against Immunoregulating Pathogens. Front Microbiol 2015; 6:1318. [PMID: 26640461 PMCID: PMC4661278 DOI: 10.3389/fmicb.2015.01318] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/09/2015] [Indexed: 12/16/2022] Open
Affiliation(s)
- Shuo Li
- Department of Microbiology, Monash University Melbourne, VIC, Australia ; Swiss Institute of Allergy and Asthma Research Davos, Switzerland
| | | | - Peter Smooker
- School of Applied Sciences, Health Innovations Research Institute, RMIT University Melbourne, VIC, Australia
| | - Eric J Gowans
- Discipline of Surgery, University of Adelaide Adelaide, SA, Australia
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Boyle MJ, Jagannathan P, Farrington LA, Eccles-James I, Wamala S, McIntyre TI, Vance HM, Bowen K, Nankya F, Auma A, Nalubega M, Sikyomu E, Naluwu K, Rek J, Katureebe A, Bigira V, Kapisi J, Tappero J, Muhindo MK, Greenhouse B, Arinaitwe E, Dorsey G, Kamya MR, Feeney ME. Decline of FoxP3+ Regulatory CD4 T Cells in Peripheral Blood of Children Heavily Exposed to Malaria. PLoS Pathog 2015; 11:e1005041. [PMID: 26182204 PMCID: PMC4504515 DOI: 10.1371/journal.ppat.1005041] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 06/23/2015] [Indexed: 12/27/2022] Open
Abstract
FoxP3+ regulatory CD4 T cells (Tregs) help to maintain the delicate balance between pathogen-specific immunity and immune-mediated pathology. Prior studies suggest that Tregs are induced by P. falciparum both in vivo and in vitro; however, the factors influencing Treg homeostasis during acute and chronic infections, and their role in malaria immunopathogenesis, remain unclear. We assessed the frequency and phenotype of Tregs in well-characterized cohorts of children residing in a region of high malaria endemicity in Uganda. We found that both the frequency and absolute numbers of FoxP3+ Tregs in peripheral blood declined markedly with increasing prior malaria incidence. Longitudinal measurements confirmed that this decline occurred only among highly malaria-exposed children. The decline of Tregs from peripheral blood was accompanied by reduced in vitro induction of Tregs by parasite antigen and decreased expression of TNFR2 on Tregs among children who had intense prior exposure to malaria. While Treg frequencies were not associated with protection from malaria, there was a trend toward reduced risk of symptomatic malaria once infected with P. falciparum among children with lower Treg frequencies. These data demonstrate that chronic malaria exposure results in altered Treg homeostasis, which may impact the development of antimalarial immunity in naturally exposed populations. In malaria endemic regions, immunity is slow to develop and does not provide substantial protection against reinfection. Rather, following repeated exposure, older children and adults eventually develop protection from most symptomatic manifestations of the infection. This may be due in part to the induction of immunoregulatory mechanisms by the P. falciparum parasite, such as FoxP3+ regulatory T cells (Tregs). Prior human studies have shown that Tregs are induced by malaria parasites both in vivo and in vitro, but the role of these cells in immunity in children who are chronically exposed to malaria remains unclear. In this study, we assessed the frequency and features of Tregs among children from areas of high malaria transmission in Uganda. We found that this regulatory T cell population declined markedly with increasing malaria episodes. This loss was associated with decreased expression of TNFR2, which is a protein implicated in stability of Tregs. Additionally, T cells from highly malaria exposed children demonstrated a reduced propensity to differentiate into Tregs following parasite stimulation. Together our data suggest that repeated episodes of malaria alter Treg homeostasis, which may influence the development of immunity to malaria in children.
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Affiliation(s)
- Michelle J. Boyle
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
- Center for Biomedical Research, The Burnet Institute, Melbourne, Australia
| | - Prasanna Jagannathan
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Lila A. Farrington
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Ijeoma Eccles-James
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Samuel Wamala
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Tara I McIntyre
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Hilary M. Vance
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Katherine Bowen
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | | | - Ann Auma
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Esther Sikyomu
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Kate Naluwu
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Victor Bigira
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - James Kapisi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Mary K Muhindo
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Moses R. Kamya
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Margaret E. Feeney
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
- Department of Pediatrics, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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