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Kim YC, Dema B, Rodriguez-Garcia R, López-Camacho C, Leoratti FMS, Lall A, Remarque EJ, Kocken CHM, Reyes-Sandoval A. Evaluation of Chimpanzee Adenovirus and MVA Expressing TRAP and CSP from Plasmodium cynomolgi to Prevent Malaria Relapse in Nonhuman Primates. Vaccines (Basel) 2020; 8:vaccines8030363. [PMID: 32640702 PMCID: PMC7564164 DOI: 10.3390/vaccines8030363] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/14/2022] Open
Abstract
Plasmodium vivax is the world’s most widely distributed human malaria parasite, with over 2.8 billion people at risk in Asia, the Americas, and Africa. The 80–90% new P. vivax malaria infections are due to relapses which suggest that a vaccine with high efficacy against relapses by prevention of hypnozoite formation could lead to a significant reduction in the prevalence of P. vivax infections. Here, we describe the development of new recombinant ChAdOx1 and MVA vectors expressing P. cynomolgi Thrombospondin Related Adhesive Protein (PcTRAP) and the circumsporozoite protein (PcCSP). Both were shown to be immunogenic in mice prior to their assessment in rhesus macaques. We confirmed good vaccine-induced humoral and cellular responses after prime-boost vaccination in rhesus macaques prior to sporozoite challenge. Results indicate that there were no significant differences between mock-control and vaccinated animals after challenge, in terms of protective efficacy measured as the time taken to 1st patency, or as number of relapses. This suggests that under the conditions tested, the vaccination with PcTRAP and PcCSP using ChAdOx1 or MVA vaccine platforms do not protect against pre-erythrocytic malaria or relapses despite good immunogenicity induced by the viral-vectored vaccines.
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Affiliation(s)
- Young Chan Kim
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK; (Y.C.K.); (B.D.); (C.L.-C.); (F.M.S.L.); (A.L.)
| | - Barbara Dema
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK; (Y.C.K.); (B.D.); (C.L.-C.); (F.M.S.L.); (A.L.)
| | - Roberto Rodriguez-Garcia
- Department of Parasitology, Biomedical Primate Research Centre (BPRC), 2288 GJ Rijswijk, The Netherlands; (R.R.-G.); (E.J.R.); (C.H.M.K.)
| | - César López-Camacho
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK; (Y.C.K.); (B.D.); (C.L.-C.); (F.M.S.L.); (A.L.)
| | - Fabiana M. S. Leoratti
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK; (Y.C.K.); (B.D.); (C.L.-C.); (F.M.S.L.); (A.L.)
| | - Amar Lall
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK; (Y.C.K.); (B.D.); (C.L.-C.); (F.M.S.L.); (A.L.)
| | - Edmond J. Remarque
- Department of Parasitology, Biomedical Primate Research Centre (BPRC), 2288 GJ Rijswijk, The Netherlands; (R.R.-G.); (E.J.R.); (C.H.M.K.)
| | - Clemens H. M. Kocken
- Department of Parasitology, Biomedical Primate Research Centre (BPRC), 2288 GJ Rijswijk, The Netherlands; (R.R.-G.); (E.J.R.); (C.H.M.K.)
| | - Arturo Reyes-Sandoval
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK; (Y.C.K.); (B.D.); (C.L.-C.); (F.M.S.L.); (A.L.)
- Correspondence: ; Tel.: +44-(0)-1865-287811
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Gomes AC, Mohsen MO, Mueller JE, Leoratti FMS, Cabral-Miranda G, Bachmann MF. Early Transcriptional Signature in Dendritic Cells and the Induction of Protective T Cell Responses Upon Immunization With VLPs Containing TLR Ligands-A Role for CCL2. Front Immunol 2019; 10:1679. [PMID: 31428084 PMCID: PMC6687836 DOI: 10.3389/fimmu.2019.01679] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 07/04/2019] [Indexed: 11/13/2022] Open
Abstract
Inducing T cell responses by therapeutic vaccination requires appropriate activation of antigen presenting cells (APCs). The use of virus-like particles (VLPs) containing Toll-like receptor (TLR) ligands has demonstrated remarkable potential in activating APCs and modulating the immune response both for prophylactic vaccines as well as immunotherapy. Here, we employed VLPs associated to TLR ligands as tools to modulate cytotoxic response mediated by CD8+ T cells and provide further insight in the development of T cell-based immunotherapy. We have investigated the in vivo transcriptional signature in dendritic cells (DCs) from mice immunized with VLPs containing distinct classes of nucleic acid and correlated the expression patterns with the efficiency of induced T cell responses. We identified key pathways activated in DCs that are involved in the appropriated induction of T cell responses and show evidence for the modulatory effect of CCL2 in CD8+ T cells responses. These insights shed light on immune networks that are pivotal for the induction of potent cytotoxic T cell responses and identify key genes for appropriate DC activation and subsequent modulation of the adaptive immune response.
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Affiliation(s)
- Ariane C Gomes
- The Jenner Institute, Oxford University, Oxford, United Kingdom
| | - Mona O Mohsen
- The Jenner Institute, Oxford University, Oxford, United Kingdom
| | | | | | | | - Martin F Bachmann
- The Jenner Institute, Oxford University, Oxford, United Kingdom.,Immunology, Inselspital, Bern, Switzerland
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Krueger CC, Thoms F, Keller E, Leoratti FMS, Vogel M, Bachmann MF. RNA and Toll-Like Receptor 7 License the Generation of Superior Secondary Plasma Cells at Multiple Levels in a B Cell Intrinsic Fashion. Front Immunol 2019; 10:736. [PMID: 31024563 PMCID: PMC6467167 DOI: 10.3389/fimmu.2019.00736] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 03/19/2019] [Indexed: 12/14/2022] Open
Abstract
Secondary plasma cells (PCs) originate from memory B cells and produce increased levels of antibodies with higher affinity compared to PCs generated during primary responses. Here we demonstrate that virus-like particles (VLPs) only induce secondary PCs in the presence of toll-like receptor (TLR) 7 and if they are loaded with RNA. Furthermore, adoptive transfer experiments demonstrate that RNA and TLR7 signaling are required for secondary PC generation, both at the level of memory B cell as well as PC differentiation. TLR7-signaling occurred in a B cell intrinsic manner as TLR7-deficient B cells in an otherwise TLR7-competent environment failed to differentiate into secondary PCs. Therefore, RNA inside VLPs is essential for the generation of memory B cells, which are competent to differentiate to secondary PCs and for the differentiation of secondary PCs themselves. While we have not tested all other TLR or non-TLR adjuvants with our VLPs, these data have obvious implications for vaccine design, as RNA packaged into VLPs is a simple way to enhance induction of memory B cells capable of generating secondary PCs.
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Affiliation(s)
- Caroline C Krueger
- Department of BioMedical Research, University of Bern, Bern, Switzerland.,Department of Immunology RIA, University Hospital Bern, Bern, Switzerland
| | - Franziska Thoms
- Department of Dermatology, University Hospital Zurich, Schlieren, Switzerland
| | - Elsbeth Keller
- Department of BioMedical Research, University of Bern, Bern, Switzerland.,Department of Immunology RIA, University Hospital Bern, Bern, Switzerland
| | - Fabiana M S Leoratti
- Department of BioMedical Research, University of Bern, Bern, Switzerland.,Department of Immunology RIA, University Hospital Bern, Bern, Switzerland
| | - Monique Vogel
- Department of BioMedical Research, University of Bern, Bern, Switzerland.,Department of Immunology RIA, University Hospital Bern, Bern, Switzerland
| | - Martin F Bachmann
- Department of BioMedical Research, University of Bern, Bern, Switzerland.,Department of Immunology RIA, University Hospital Bern, Bern, Switzerland.,Nuffield Department of Medicine, The Henry Wellcome Building for Molecular Physiology, The Jenner Institute, University of Oxford, Oxford, United Kingdom
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Zha L, Leoratti FMS, He L, Mohsen MO, Cragg M, Storni F, Vogel M, Bachmann MF. An unexpected protective role of low-affinity allergen-specific IgG through the inhibitory receptor FcγRIIb. J Allergy Clin Immunol 2018; 142:1529-1536.e6. [PMID: 29391255 DOI: 10.1016/j.jaci.2017.09.054] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 09/15/2017] [Accepted: 09/21/2017] [Indexed: 11/19/2022]
Abstract
BACKGROUND Induction of allergen-specific IgG antibodies is a critical parameter for successful allergen-specific immunotherapy. IgG antibodies can inhibit IgE-mediated mast cell activation through direct allergen neutralization or through the inhibitory receptor FcγRIIb. The affinity of IgE antibodies to the allergen has been shown to be critical for cellular activation. OBJECTIVE Here we addressed the question of affinity thresholds of allergen-specific IgG antibodies for inhibition of mast cell activation using 2 different mAbs against the major cat allergen Fel d 1 both in vitro and in vivo in mice. METHODS Sequences of the 2 high-affinity mAbs were back-mutated to germline, resulting in low-affinity (10-7 mol/L) antibodies of the exact same specificity. RESULTS Using these newly generated recombinant antibodies, we demonstrate that low-affinity antibodies are still able to inhibit mast cell activation through FcγRIIb but do not neutralize the allergen. CONCLUSION Antibody affinity dictates the mechanism of mast cell inhibition, and IgG antibodies triggering the inhibitory FcγRIIb pathway can show a broader cross-reactivity pattern than previously thought. This indicates that allergen-specific immunotherapy generates a larger protective umbrella of inhibitory IgG antibodies than previously appreciated.
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Affiliation(s)
- Lisha Zha
- Immunology, RIA, Inselspital, University Hospital Bern, Bern, Switzerland
| | | | - Lichun He
- Biozentrum, University of Basel, Basel, Switzerland
| | - Mona O Mohsen
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Mark Cragg
- Antibody and Vaccine Group, Cancer Sciences Unit, Faculty of Medicine, General Hospital, University of Southampton, Southampton, United Kingdom
| | - Federico Storni
- Immunology, RIA, Inselspital, University Hospital Bern, Bern, Switzerland
| | - Monique Vogel
- Immunology, RIA, Inselspital, University Hospital Bern, Bern, Switzerland.
| | - Martin F Bachmann
- Immunology, RIA, Inselspital, University Hospital Bern, Bern, Switzerland; Jenner Institute, University of Oxford, Oxford, United Kingdom.
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Costa PAC, Leoratti FMS, Figueiredo MM, Tada MS, Pereira DB, Junqueira C, Soares IS, Barber DL, Gazzinelli RT, Antonelli LRV. Induction of Inhibitory Receptors on T Cells During Plasmodium vivax Malaria Impairs Cytokine Production. J Infect Dis 2015; 212:1999-2010. [PMID: 26019284 DOI: 10.1093/infdis/jiv306] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/15/2015] [Indexed: 01/29/2023] Open
Abstract
The function and regulation of the immune response triggered during malaria is complex and poorly understood, and there is a particular paucity of studies conducted in humans infected with Plasmodium vivax. While it has been proposed that T-cell-effector responses are crucial for protection against blood-stage malaria in mice, the mechanisms behind this in humans remain poorly understood. Experimental models of malaria have shown that the regulatory molecules, cytotoxic T-lymphocyte attenuator-4 (CTLA-4), lymphocyte activation gene-3 (LAG-3), and programmed death-1 (PD-1) are involved in the functional impairment of T cells during infection. Our goal was to define the role of these molecules during P. vivax malaria. We demonstrate that infection triggers the expression of regulatory molecules on T cells. The pattern of expression differs in CD4(+) and CD8(+) T cells. Higher frequencies of CD4(+) express more than 1 regulatory molecule compared to CD8(+) T cells. Moreover, lower proportions of CD4(+) T cells coexpress regulatory molecules, but are still able to proliferate. Importantly, simultaneously blockade of the CLTA-4, PD-1, and T-cell immunoglobulin and mucin-3 signaling restores the cytokine production by antigen-specific cells. These data support the hypothesis that upregulation of inhibitory receptors on T cells during P. vivax malaria impairs parasite-specific T-cell effector function.
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Affiliation(s)
- Pedro A C Costa
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais
| | - Fabiana M S Leoratti
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais
| | - Maria M Figueiredo
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais
| | - Mauro S Tada
- Centro de Pesquisas em Medicina Tropical de Rondônia, Porto Velho
| | - Dhelio B Pereira
- Centro de Pesquisas em Medicina Tropical de Rondônia, Porto Velho
| | - Caroline Junqueira
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais
| | - Irene S Soares
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Brazil
| | - Daniel L Barber
- T Lymphocyte Biology Unit, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Ricardo T Gazzinelli
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lis R V Antonelli
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais
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Antonelli LRV, Leoratti FMS, Costa PAC, Rocha BC, Diniz SQ, Tada MS, Pereira DB, Teixeira-Carvalho A, Golenbock DT, Gonçalves R, Gazzinelli RT. The CD14+CD16+ inflammatory monocyte subset displays increased mitochondrial activity and effector function during acute Plasmodium vivax malaria. PLoS Pathog 2014; 10:e1004393. [PMID: 25233271 PMCID: PMC4169496 DOI: 10.1371/journal.ppat.1004393] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 08/11/2014] [Indexed: 01/22/2023] Open
Abstract
Infection with Plasmodium vivax results in strong activation of monocytes, which are important components of both the systemic inflammatory response and parasite control. The overall goal of this study was to define the role of monocytes during P. vivax malaria. Here, we demonstrate that P. vivax-infected patients display significant increase in circulating monocytes, which were defined as CD14(+)CD16- (classical), CD14(+)CD16(+) (inflammatory), and CD14loCD16(+) (patrolling) cells. While the classical and inflammatory monocytes were found to be the primary source of pro-inflammatory cytokines, the CD16(+) cells, in particular the CD14(+)CD16(+) monocytes, expressed the highest levels of activation markers, which included chemokine receptors and adhesion molecules. Morphologically, CD14(+) were distinguished from CD14lo monocytes by displaying larger and more active mitochondria. CD14(+)CD16(+) monocytes were more efficient in phagocytizing P. vivax-infected reticulocytes, which induced them to produce high levels of intracellular TNF-α and reactive oxygen species. Importantly, antibodies specific for ICAM-1, PECAM-1 or LFA-1 efficiently blocked the phagocytosis of infected reticulocytes by monocytes. Hence, our results provide key information on the mechanism by which CD14(+)CD16(+) cells control parasite burden, supporting the hypothesis that they play a role in resistance to P. vivax infection.
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Affiliation(s)
- Lis R. V. Antonelli
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
| | - Fabiana M. S. Leoratti
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Pedro A. C. Costa
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Bruno C. Rocha
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Suelen Q. Diniz
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Mauro S. Tada
- Centro de Pesquisas em Medicina Tropical de Rondônia, Porto Velho, Rondônia, Brazil
| | - Dhelio B. Pereira
- Centro de Pesquisas em Medicina Tropical de Rondônia, Porto Velho, Rondônia, Brazil
| | - Andrea Teixeira-Carvalho
- Laboratório de Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Douglas T. Golenbock
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Ricardo Gonçalves
- Departamento de Patologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo T. Gazzinelli
- Laboratório de Immunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Leoratti FMS, Durlacher RR, Lacerda MVG, Alecrim MG, Ferreira AW, Sanchez MCA, Moraes SL. Pattern of humoral immune response to Plasmodium falciparum blood stages in individuals presenting different clinical expressions of malaria. Malar J 2008; 7:186. [PMID: 18816374 PMCID: PMC2559846 DOI: 10.1186/1475-2875-7-186] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Accepted: 09/24/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The development of protective immunity against malaria is slow and to be maintained, it requires exposure to multiple antigenic variants of malaria parasites and age-associated maturation of the immune system. Evidence that the protective immunity is associated with different classes and subclasses of antibodies reveals the importance of considering the quality of the response. In this study, we have evaluated the humoral immune response against Plasmodium falciparum blood stages of individuals naturally exposed to malaria who live in endemic areas of Brazil in order to assess the prevalence of different specific isotypes and their association with different malaria clinical expressions. METHODS Different isotypes against P. falciparum blood stages, IgG, IgG1, IgG2, IgG3, IgG4, IgM, IgE and IgA, were determined by ELISA. The results were based on the analysis of different clinical expressions of malaria (complicated, uncomplicated and asymptomatic) and factors related to prior malaria exposure such as age and the number of previous clinical malaria attacks. The occurrence of the H131 polymorphism of the FcgammaIIA receptor was also investigated in part of the studied population. RESULTS The highest levels of IgG, IgG1, IgG2 and IgG3 antibodies were observed in individuals with asymptomatic and uncomplicated malaria, while highest levels of IgG4, IgE and IgM antibodies were predominant among individuals with complicated malaria. Individuals reporting more than five previous clinical malaria attacks presented a predominance of IgG1, IgG2 and IgG3 antibodies, while IgM, IgA and IgE antibodies predominated among individuals reporting five or less previous clinical malaria attacks. Among individuals with uncomplicated and asymptomatic malaria, there was a predominance of high-avidity IgG, IgG1, IgG2 antibodies and low-avidity IgG3 antibodies. The H131 polymorphism was found in 44.4% of the individuals, and the highest IgG2 levels were observed among asymptomatic individuals with this allele, suggesting the protective role of IgG2 in this population. CONCLUSION Together, the results suggest a differential regulation in the anti-P. falciparum antibody pattern in different clinical expressions of malaria and showed that even in unstable transmission areas, protective immunity against malaria can be observed, when the appropriated antibodies are produced.
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Affiliation(s)
- Fabiana M S Leoratti
- Institute of Tropical Medicine of São Paulo, University of São Paulo, Av, Dr, Enéas de Carvalho Aguiar, 470, 05403-000, São Paulo, Brazil.
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Suárez-Mutis MC, Cuervo P, Leoratti FMS, Moraes-Avila SL, Ferreira AW, Fernandes O, Coura JR. Cross sectional study reveals a high percentage of asymptomatic Plasmodium vivax infection in the Amazon Rio Negro area, Brazil. Rev Inst Med Trop Sao Paulo 2007; 49:159-64. [PMID: 17625693 DOI: 10.1590/s0036-46652007000300005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Accepted: 11/16/2006] [Indexed: 11/22/2022] Open
Abstract
A parasitological, clinical, serological and molecular cross-sectional study carried out in a highly endemic malaria area of Rio Negro in the Amazon State, Brazil, revealed a high prevalence of asymptomatic Plasmodium vivax infection. A total of 109 persons from 25 families were studied in five villages. Ninety-nine inhabitants (90.8%) had at least one previous episode of malaria. Serology showed 85.7% and 46.9% of positivity when P. falciparum antigens and P. vivax MSP-1, respectively, were used. Twenty blood samples were PCR positive for P. vivax (20.4%) and no P. falciparum infection was evidenced by this technique. No individual presenting positive PCR reaction had clinical malaria during the survey neither in the six months before nor after, confirming that they were cases of asymptomatic infection. Only one 12 year old girl presented a positive thick blood smear for P. vivax. This is the first description of asymptomatic Plasmodium infection in this area studied.
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Affiliation(s)
- Martha C Suárez-Mutis
- Laboratório de Doenças Parasitarias, Departamento de Medicina Tropical, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
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Kanunfre KA, Leoratti FMS, Hoffmann EHE, Durlacher RR, Ferreira AW, Moraes-Avila SL, Ferreira MU. Differential recognition of Plasmodium falciparum merozoite surface protein 2 variants by antibodies from malaria patients in Brazil. Clin Diagn Lab Immunol 2003; 10:973-6. [PMID: 12965937 PMCID: PMC193907 DOI: 10.1128/cdli.10.5.973-976.2003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Four variants of merozoite surface protein 2 (MSP-2) of Plasmodium falciparum were used in serology to examine whether changes in repeat units affect its recognition by antibodies during infection with parasites of known MSP-2 types. The results indicate that variation in MSP-2 repeats may represent a mechanism for parasite immune evasion.
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Affiliation(s)
- Kelly A Kanunfre
- Institute of Tropical Medicine of São Paulo, University of São Paulo, São Paulo, Brazil
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