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O'Flaherty K, Maguire J, Simpson JA, Fowkes FJI. Immunity as a predictor of anti-malarial treatment failure: a systematic review. Malar J 2017; 16:158. [PMID: 28427418 PMCID: PMC5397737 DOI: 10.1186/s12936-017-1815-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 04/09/2017] [Indexed: 01/21/2023] Open
Abstract
Background Naturally acquired immunity can reduce parasitaemia and potentially influence anti-malarial treatment outcomes; however, evidence for this in the current literature provides conflicted results. The available evidence was synthesized to determine and quantify the association between host immunity and anti-malarial treatment failure. Methods Four databases were searched to identify studies investigating malaria antibody levels in patients receiving anti-malarial treatment for symptomatic malaria with treatment failure recorded according to the World Health Organization classification. Odds ratios or hazard ratios were extracted or calculated to quantify the association between malarial antibody levels and treatment failure, and findings from different studies were visualized using forest plots. Results Eight studies, including patients with falciparum malaria treated with mono- and combination therapy of artemisinin derivatives, sulfadoxine, pyrimethamine and chloroquine, were identified. Reported and calculated effect estimates varied greatly between studies, even those assessing the same antigens and treatments. An association between blood-stage IgG responses and treatment efficacy was observed. The greatest magnitudes of effect were observed for artemisinin [OR/HR (95% CI) range 0.02 (0.00, 0.45)–1.08 (0.57, 2.06)] and chloroquine [0.24 (0.04, 1.37)–0.32 (0.05, 1.96)] treatments, and larger magnitudes of effect were observed for variant surface antigen responses [0.02 (0.00, 0.45)–1.92 (0.94, 3.91)] when compared with merozoite specific responses [0.24 (0.04, 1.37)–2.83 (1.13, 7.09)]. Conclusions Naturally acquired malarial immunity is associated with reduced anti-malarial treatment failure in malaria endemic populations. Anti-malarial IgG effects treatment outcome differently for different anti-malarial drugs and antigen targets, and had the greatest impact during treatment with the current first-line treatments, the artemisinins. This has implications for the assessment of the therapeutic efficacy of anti-malarials, particularly in the context of emerging artemisinin resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1815-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katherine O'Flaherty
- Macfarlane Burnet Institute of Medical Research, Melbourne, VIC, 3004, Australia.,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, 3010, Australia
| | - Julia Maguire
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, 3010, Australia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, 3010, Australia
| | - Freya J I Fowkes
- Macfarlane Burnet Institute of Medical Research, Melbourne, VIC, 3004, Australia. .,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, 3010, Australia. .,Department of Epidemiology and Preventive Medicine and Department of Infectious Diseases, Monash University, Melbourne, 3800, Australia.
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Mvé-Ondo B, Nkoghe D, Arnathau C, Rougeron V, Bisvigou U, Mouele LY, Boundenga L, Durand P, Elguero E, Lemmers S, Délicat-Loembet LM, Diamella-Moukodoum N, Paupy C, Renaud F, Prugnolle F, Ollomo B. Genetic diversity of Plasmodium falciparum isolates from Baka Pygmies and their Bantu neighbours in the north of Gabon. Malar J 2015; 14:395. [PMID: 26450086 PMCID: PMC4599724 DOI: 10.1186/s12936-015-0862-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 08/23/2015] [Indexed: 11/25/2022] Open
Abstract
Background There have been many reports on the population genetic structure of Plasmodium falciparum from different endemic regions especially sub-Saharan Africa. However, few studies have been performed on neglected populations, such as the Pygmy populations. In this study, the population genetic structure of P. falciparum was investigated in the Baka Pygmies of Gabon and compared to that observed in neighboring villages composed mostly of Bantu farmers. Methods A total of 342 blood samples were collected from 170 Baka Pygmies and 172 Bantus in the north of Gabon (Woleu Ntem Province). Plasmodium infections were characterized by sequencing a portion of the parasite cytochrome b gene. Population genetic structure of P. falciparum in the different villages was analysed using microsatellite markers and genes coding for antigenic proteins (MSP1, MSP2, GLURP, and EBA-175). Results Overall, prevalence of P. falciparum was around 57 % and no significant difference of prevalence was observed between Pygmies and Bantus. No significant differences of population genetic structure of P. falciparum was found between Pygmy and Bantu people except for one antigen-coding gene, glurp, for which genetic data suggested the existence of a potentially disruptive selection acting on this gene in the two types of populations. The genetic structure of P. falciparum followed a pattern of isolation by distance at the scale of the study. Conclusion The prevalence and genetic diversity of P. falciparum observed in Baka demonstrates a significant transmission of the parasite in this population, and some exchanges of parasites with Bantu neighbours. Despite that, some antigen-coding genes seem to have had a particular evolutionary trajectory in certain Pygmy populations due to specific local human and/or mosquito characteristics. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0862-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bertrand Mvé-Ondo
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Ecole Doctorale Régionale d'Afrique Centrale en Infectiologie Tropicale, BP 876, Franceville, Gabon.
| | - Dieudonné Nkoghe
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Ministry of Health, BP 50, Libreville, Gabon.
| | - Céline Arnathau
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Virginie Rougeron
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | | | - Lauriane Yacka Mouele
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Fac de Médecine, UMR-BIOMED, BP 8507, Libreville, Gabon.
| | - Larson Boundenga
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Département de Biologie Animale, Faculté des Sciences et Techniques, Laboratoire d'Écologie et Biologie évolutive, Université Cheikh AntaDiop de Dakar, BP 5005, Dakar, Senegal.
| | - Patrick Durand
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Eric Elguero
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Simone Lemmers
- Department of Anthropology, Durham University, Dawson Building, South Road, Durham, DH1 3LE, England, UK.
| | | | - Nancy Diamella-Moukodoum
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon.
| | - Christophe Paupy
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - François Renaud
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Franck Prugnolle
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Benjamin Ollomo
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Fac de Médecine, UMR-BIOMED, BP 8507, Libreville, Gabon.
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Keh CE, Jha AR, Nzarubara B, Lanar DE, Dutta S, Theisen M, Rosenthal PJ, Dorsey G, Nixon DF, Greenhouse B. Associations between antibodies to a panel of Plasmodium falciparum specific antigens and response to sub-optimal antimalarial therapy in Kampala, Uganda. PLoS One 2012; 7:e52571. [PMID: 23285095 PMCID: PMC3526588 DOI: 10.1371/journal.pone.0052571] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 11/19/2012] [Indexed: 02/06/2023] Open
Abstract
Background Antibodies are important in the control of blood stage Plasmodium falciparum infection. It is unclear which antibody responses are responsible for, or even associated with protection, partly due to confounding by heterogeneous exposure. Assessment of response to partially effective antimalarial therapy, which requires the host to assist in clearing parasites, offers an opportunity to measure protection independent of exposure. Methods A cohort of children aged 1–10 years in Kampala, Uganda were treated with amodiaquine+sulfadoxine-pyrimethamine for uncomplicated malaria. Serum samples from the time of malaria diagnosis and 14 days later were analyzed for total IgG to 8 P. falciparum antigens using a quantitative indirect ELISA. Associations between antibody levels and risk of treatment failure were estimated using Cox proportional hazard regression. Results Higher levels of antibodies to apical membrane antigen 1 (AMA-1), but to none of the other 7 antigens were significantly associated with protection against treatment failure (HR 0.57 per 10-fold increase in antibody level, CI 0.41–0.79, p = 0.001). Protection increased consistently across the entire range of antibody levels. Conclusions Measurement of antibody levels to AMA-1 at the time of malaria may offer a quantitative biomarker of blood stage immunity to P. falciparum, a tool which is currently lacking.
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Affiliation(s)
- Chris E. Keh
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Aashish R. Jha
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | | | - David E. Lanar
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Sheetij Dutta
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Michael Theisen
- Department of Clinical Biochemistry and Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Philip J. Rosenthal
- 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
| | - Douglas F. Nixon
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Sarr JB, Samb B, Sagna AB, Fortin S, Doucoure S, Sow C, Senghor S, Gaayeb L, Guindo S, Schacht AM, Rogerie F, Hermann E, Dia I, Konate L, Riveau G, Remoue F. Differential acquisition of human antibody responses to Plasmodium falciparum according to intensity of exposure to Anopheles bites. Trans R Soc Trop Med Hyg 2012; 106:460-7. [PMID: 22721883 DOI: 10.1016/j.trstmh.2012.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 05/17/2012] [Accepted: 05/17/2012] [Indexed: 11/16/2022] Open
Abstract
Malaria immunity is modulated by many environmental and epidemiological factors. This study evaluates the influence of a hitherto unstudied environmental-epidemiological factor, namely the impact of human exposure to Anopheles bites on the isotype profile of acquired antibody responses to Plasmodium falciparum. In two Senegalese villages where the intensity of exposure to Anopheles bites was markedly different (high and low exposure), specific IgG1 and IgG3 responses to P. falciparum whole schizont extract (WSE) and circumsporozoite protein (CSP) were evaluated at the peak of Anopheles exposure (September) and later (December) in a cohort of 120 children aged 3-8 years. Multivariate analysis showed a significantly lower IgG1 response against P. falciparum WSE and CSP in children highly exposed to Anopheles bites (Gankette) compared to those who were weakly exposed (Mboula). In contrast, in both villages, parasitemia and increasing age were strongly associated with higher IgG1 and IgG3 levels. We hypothesize that high exposure to Anopheles bites could inhibit IgG1-dependent responsiveness to P. falciparum known to induce protective immune responses against malaria. The impact of mosquito saliva on the regulation of specific protective immunity may need to be taken into account in epidemiological studies and trials for malaria vaccines.
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Affiliation(s)
- Jean Biram Sarr
- Unité de recherche mixte MIVEGEC (IRD 224-CNRS 5290-UM1-UM2), Montpellier, France.
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5
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Quelhas D, Puyol L, Quintó L, Nhampossa T, Serra-Casas E, Macete E, Aide P, Sanz S, Aponte JJ, Doolan DL, Alonso PL, Menéndez C, Dobaño C. Intermittent preventive treatment with sulfadoxine-pyrimethamine does not modify plasma cytokines and chemokines or intracellular cytokine responses to Plasmodium falciparum in Mozambican children. BMC Immunol 2012; 13:5. [PMID: 22280502 PMCID: PMC3398260 DOI: 10.1186/1471-2172-13-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 01/26/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cytokines and chemokines are key mediators of anti-malarial immunity. We evaluated whether Intermittent Preventive Treatment in infants with Sulfadoxine-Pyrimethamine (IPTi-SP) had an effect on the acquisition of these cellular immune responses in Mozambican children. Multiple cytokines and chemokines were quantified in plasma by luminex, and antigen-specific cytokine production in whole blood was determined by intracellular cytokine staining and flow cytometry, at ages 5, 9, 12 and 24 months. RESULTS IPTi-SP did not significantly affect the proportion of CD3+ cells producing IFN-γ, IL-4 or IL-10. Overall, plasma cytokine or chemokine concentrations did not differ between treatment groups. Th1 and pro-inflammatory responses were higher than Th2 and anti-inflammatory responses, respectively, and IFN-γ:IL-4 ratios were higher for placebo than for SP recipients. Levels of cytokines and chemokines varied according to age, declining from 5 to 9 months. Plasma concentrations of IL-10, IL-12 and IL-13 were associated with current infection or prior malaria episodes. Higher frequencies of IFN-γ and IL-10 producing CD3+ cells and elevated IL-10, IFN-γ, MCP-1 and IL-13 in plasma were individually associated with increased malaria incidence, at different time points. When all markers were analyzed together, only higher IL-17 at 12 months was associated with lower incidence of malaria up to 24 months. CONCLUSIONS Our work has confirmed that IPTi-SP does not negatively affect the development of cellular immune response during early childhood. This study has also provided new insights as to how these cytokine responses are acquired upon age and exposure to P. falciparum, as well as their associations with malaria susceptibility. TRIAL REGISTRATION ClinicalTrials.gov: NCT00209795.
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Affiliation(s)
- Diana Quelhas
- Centro de Investigação em Saúde da Manhiça, Manhiça, Mozambique
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Monatrakul P, Mungthin M, Dondorp AM, Krudsood S, Udomsangpetch R, Wilairatana P, White NJ, Chotivanich K. Modulating effects of plasma containing anti-malarial antibodies on in vitro anti-malarial drug susceptibility in Plasmodium falciparum. Malar J 2010; 9:326. [PMID: 21078202 PMCID: PMC2993733 DOI: 10.1186/1475-2875-9-326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 11/16/2010] [Indexed: 11/17/2022] Open
Abstract
Background The efficacy of anti-malarial drugs is determined by the level of parasite susceptibility, anti-malarial drug bioavailability and pharmacokinetics, and host factors including immunity. Host immunity improves the in vivo therapeutic efficacy of anti-malarial drugs, but the mechanism and magnitude of this effect has not been characterized. This study characterized the effects of 'immune' plasma to Plasmodium falciparumon the in vitro susceptibility of P. falciparum to anti-malarial drugs. Methods Titres of antibodies against blood stage antigens (mainly the ring-infected erythrocyte surface antigen [RESA]) were measured in plasma samples obtained from Thai patients with acute falciparum malaria. 'Immune' plasma was selected and its effects on in vitro parasite growth and multiplication of the Thai P. falciparum laboratory strain TM267 were assessed by light microscopy. The in vitro susceptibility to quinine and artesunate was then determined in the presence and absence of 'immune' plasma using the 3H-hypoxanthine uptake inhibition method. Drug susceptibility was expressed as the concentrations causing 50% and 90% inhibition (IC50 and IC90), of 3H-hypoxanthine uptake. Results Incubation with 'immune' plasma reduced parasite maturation and decreased parasite multiplication in a dose dependent manner. 3H-hypoxanthine incorporation after incubation with 'immune' plasma was decreased significantly compared to controls (median [range]; 181.5 [0 to 3,269] cpm versus 1,222.5 [388 to 5,932] cpm) (p= 0.001). As a result 'immune' plasma reduced apparent susceptibility to quinine substantially; median (range) IC50 6.4 (0.5 to 23.8) ng/ml versus 221.5 (174.4 to 250.4) ng/ml (p = 0.02), and also had a borderline effect on artesunate susceptibility; IC50 0.2 (0.02 to 0.3) ng/ml versus 0.8 (0.2 to 2.3) ng/ml (p = 0.08). Effects were greatest at low concentrations, changing the shape of the concentration-effect relationship. IC90 values were not significantly affected; median (range) IC90 448.0 (65 to > 500) ng/ml versus 368.8 (261 to 501) ng/ml for quinine (p > 0.05) and 17.0 (0.1 to 29.5) ng/ml versus 7.6 (2.3 to 19.5) ng/ml for artesunate (p = 0.4). Conclusions 'Immune' plasma containing anti-malarial antibodies inhibits parasite development and multiplication and increases apparent in vitro anti-malarial drug susceptibility of P. falciparum. The IC90 was much less affected than the IC50 measurement.
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Affiliation(s)
- Preeyaporn Monatrakul
- Department of Clinical Tropical Medicine, Mahidol University, 420/6 Rajvithi, Bangkok, Thailand
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Rogerson SJ, Wijesinghe RS, Meshnick SR. Host immunity as a determinant of treatment outcome in Plasmodium falciparum malaria. THE LANCET. INFECTIOUS DISEASES 2010; 10:51-9. [PMID: 20129149 DOI: 10.1016/s1473-3099(09)70322-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Host immunity is an important but poorly understood determinant of antimalarial efficacy, influencing the outcome of prevention and treatment trials. Variations in host immunity might explain why factors such as host genetics, age, pregnancy, infection with HIV, parasite density, and malaria transmission intensity, can raise or lower apparent cure rates. Recently, attempts have been made to characterise immunological correlates of treatment outcome in Plasmodium falciparum malaria, but not yet for Plasmodium vivax. A better understanding of such correlates might improve trials of antimalarial drugs and provide leads for vaccine development. Greater understanding of the relation between host immunity and treatment outcome is crucial to making informed choices about the use of safe but partly effective drugs for malaria prevention in children and pregnant women. With increasing malaria control efforts worldwide, declining population immunity might alter drug response profiles. Improved methods for assessing antimalarial immunity will strengthen malaria control efforts.
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Affiliation(s)
- Stephen J Rogerson
- Department of Medicine, University of Melbourne, Melbourne, VIC, Australia.
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Duah NO, Miles DJC, Whittle HC, Conway DJ. Acquisition of antibody isotypes against Plasmodium falciparum blood stage antigens in a birth cohort. Parasite Immunol 2010; 32:125-34. [PMID: 20070826 PMCID: PMC2814092 DOI: 10.1111/j.1365-3024.2009.01165.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/20/2009] [Indexed: 11/28/2022]
Abstract
Information on the period during which infants lose their maternally derived antibodies to malaria and begin to acquire naturally their own immune responses against parasite antigens is crucial for understanding when malaria vaccines may be best administered. This study investigated the rates of decline and acquisition of serum antibody isotypes IgG1, IgG2, IgG3, IgG4, IgM and IgA to Plasmodium falciparum antigens apical membrane antigen (AMA1), merozoite surface proteins (MSP1-19, MSP2 and MSP3) in a birth cohort of 53 children living in an urban area in the Gambia, followed over the first 3 years of life (sampled at birth, 4, 9, 18 and 36 months). Antigen-specific maternally transferred antibody isotypes of all IgG subclasses were detected at birth and were almost totally depleted by 4 months of age. Acquisition of specific antibody isotypes to the antigens began with IgM, followed by IgG1 and IgA. Against the MSP2 antigen, IgG1 but not IgG3 responses were observed in the children, in contrast with the maternally derived antibodies to this antigen that were mostly IgG3. This confirms that IgG subclass responses to MSP2 are strongly dependent on age or previous malaria experience, polarized towards IgG1 early in life and to IgG3 in older exposed individuals.
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Affiliation(s)
- N O Duah
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
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Feng G, Aitken E, Yosaatmadja F, Kalilani L, Meshnick SR, Jaworowski A, Simpson JA, Rogerson SJ. Antibodies to variant surface antigens of Plasmodium falciparum-infected erythrocytes are associated with protection from treatment failure and the development of anemia in pregnancy. J Infect Dis 2009; 200:299-306. [PMID: 19500037 DOI: 10.1086/599841] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND In pregnancy-associated malaria (PAM), Plasmodium falciparum-infected erythrocytes (IEs) express variant surface antigens (VSA-PAM) that evade existing immunity and mediate placental sequestration. Antibodies to VSA-PAM develop with gravidity and block placental adhesion or opsonize IEs for phagocytic clearance, helping to prevent maternal anemia and low birth weight in infants. METHODS Using serum samples from 141 pregnant Malawian women with parasitemia enrolled in a randomized trial of antimalarials and VSA-PAM-expressing CS2 IEs, we quantified levels of immunoglobulin (Ig) G to VSA-PAM by flow cytometry and levels of opsonizing antibodies by measuring uptake of IEs by THP1 promonocytes. RESULTS After controlling for gravidity and antimalarial treatment, higher levels of IgG to VSA-PAM were associated with decreased anemia at delivery (odds ratio [OR], 0.66 [95% confidence interval {CI}, 0.46-0.93]; P = .018) and were weakly associated with decreased parasitological failure (OR, 0.78 [95% CI, 0.60-1.03]; P = .075), especially reinfection (OR, 0.73 [95% CI, 0.53-1.01]; P = .057). Higher levels of opsonizing antibodies to CS2 IEs were associated with less maternal anemia (OR, 0.31 [95% CI, 0.13-0.74]; P = .008) and treatment failure (OR, 0.48 [95% CI, 0.25-0.90]; P = .023), primarily because of recrudescent infection (OR, 0.49 [95% CI, 0.21-1.12]; P = .089). CONCLUSION Higher levels of both IgG antibodies to VSA-PAM and opsonizing antibodies, a functional measure of immunity, correlate with parasite clearance and less anemia in pregnancy malaria.
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Affiliation(s)
- Gaoqian Feng
- Department of Medicine, Royal Melbourne Hospital, Melbourne, Australia
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Dodoo D, Aikins A, Kusi KA, Lamptey H, Remarque E, Milligan P, Bosomprah S, Chilengi R, Osei YD, Akanmori BD, Theisen M. Cohort study of the association of antibody levels to AMA1, MSP119, MSP3 and GLURP with protection from clinical malaria in Ghanaian children. Malar J 2008; 7:142. [PMID: 18664257 PMCID: PMC2529305 DOI: 10.1186/1475-2875-7-142] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 07/29/2008] [Indexed: 11/24/2022] Open
Abstract
Background Antigen-specific antibody-mediated immune responses play an important role in natural protection against clinical malaria, but conflicting estimates of this association have emerged from immuno-epidemiological studies in different geographical settings. This study was aimed at assessing in a standardized manner the relationship between the antibody responses to four malaria vaccine candidate antigens and protection from clinical malaria, in a cohort of Ghanaian children. Methods Standardized ELISA protocols were used to measure isotype and IgG subclass levels to Apical Membrane Antigen 1 (AMA1), Merozoite Surface Protein 1–19 (MSP119), Merozoite Surface Protein 3 (MSP3) and Glutamate Rich Protein (GLURP) antigens in plasma samples from 352 Ghanaian children, aged three to 10 years with subsequent malaria surveillance for nine months. This is one of a series of studies in different epidemiological settings using the same standardized ELISA protocols to permit comparisons of results from different laboratories. Results The incidence rate of malaria was 0.35 episodes per child per year. Isotype and IgG subclasses for all antigens investigated increased with age, while the risk of malaria decreased with age. After adjusting for age, higher levels of IgG to GLURP, MSP119, MSP3 and IgM to MSP119, MSP3 and AMA1 were associated with decreased malaria incidence. Of the IgG subclasses, only IgG1 to MSP119 was associated with reduced incidence of clinical malaria. A previous study in the same location failed to find an association of antibodies to MSP119 with clinical malaria. The disagreement may be due to differences in reagents, ELISA and analytical procedures used in the two studies. When IgG, IgM and IgG subclass levels for all four antigens were included in a combined model, only IgG1 [(0.80 (0.67–0.97), p = 0.018)] and IgM [(0.48 (0.32–0.72), p < 0.001)] to MSP119 were independently associated with protection from malaria. Conclusion Using standardized procedures, the study has confirmed the importance of antibodies to MSP119 in reducing the risk of clinical malaria in Ghanaian children, thus substantiating its potential as a malaria vaccine candidate.
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Affiliation(s)
- Daniel Dodoo
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
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Enevold A, Nkya WMMM, Theisen M, Vestergaard LS, Jensen AT, Staalsoe T, Theander TG, Bygbjerg IC, Alifrangis M. Potential impact of host immunity on malaria treatment outcome in Tanzanian children infected with Plasmodium falciparum. Malar J 2007; 6:153. [PMID: 18021388 PMCID: PMC2206045 DOI: 10.1186/1475-2875-6-153] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Accepted: 11/16/2007] [Indexed: 11/25/2022] Open
Abstract
Background In malaria endemic areas children may recover from malaria after chemotherapy in spite of harbouring genotypically drug-resistant Plasmodium falciparum. This phenomenon suggests that there is a synergy between drug treatment and acquired immunity. This hypothesis was examined in an area of moderately intense transmission of P. falciparum in Tanzania during a drug trail with sulphadoxine-pyrimethamine (SP) or amodiaquine (AQ). Methods One hundred children with uncomplicated malaria were treated with either SP or AQ and followed for 28 days. Mutations in parasite genes related to SP and AQ-resistance as well as human sickle cell trait and alpha-thalassaemia were determined using PCR and sequence-specific oligonucleotide probes and enzyme-linked immunosorbent assay (SSOP-ELISA), and IgG antibody responses to a panel of P. falciparum antigens were assessed and related to treatment outcome. Results Parasitological or clinical treatment failure (TF) was observed in 68% and 38% of children receiving SP or AQ, respectively. In those with adequate clinical and parasitological response (ACPR) compared to children with TF, and for both treatment regimens, prevalence and levels of anti-Glutamate-rich Protein (GLURP)-specific IgG antibodies were significantly higher (P < 0.001), while prevalence of parasite haplotypes associated with SP and AQ resistance was lower (P = 0.02 and P = 0.07, respectively). Interestingly, anti-GLURP-IgG antibodies were more strongly associated with treatment outcome than parasite resistant haplotypes, while the IgG responses to none of the other 11 malaria antigens were not significantly associated with ACPR. Conclusion These findings suggest that GLURP-specific IgG antibodies in this setting contribute to clearance of drug-resistant infections and support the hypothesis that acquired immunity enhances the clinical efficacy of drug therapy. The results should be confirmed in larger scale with greater sample size and with variation in transmission intensity.
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Affiliation(s)
- Anders Enevold
- Centre for Medical Parasitology, Institute of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
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