101
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Antimalarial activity of granzyme B and its targeted delivery by a granzyme B-single-chain Fv fusion protein. Antimicrob Agents Chemother 2014; 59:669-72. [PMID: 25313223 DOI: 10.1128/aac.04190-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We present here the first evidence that granzyme B acts against Plasmodium falciparum (50% inhibitory concentration [IC50], 1,590 nM; 95% confidence interval [95% CI], 1,197 to 2,112 nM). We created a novel antimalarial fusion protein consisting of granzyme B fused to a merozoite surface protein 4 (MSP4)-specific single-chain Fv protein (scFv), which targets the enzyme to infected erythrocytes, with up to an 8-fold reduction in the IC50 (176 nM; 95% CI, 154 to 202 nM). This study confirms the therapeutic efficacies of recombinant antibody-mediated antimalarial immunotherapeutics based on granzyme B.
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102
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Chaitanya RK, Sridevi P, Kumar KS, Mastan BS, Kumar KA, Dutta-Gupta A. Expression analysis of reactive oxygen species detoxifying enzyme genes in Anopheles stephensi during Plasmodium berghei midgut invasion. ASIAN PAC J TROP MED 2014. [DOI: 10.1016/s1995-7645(14)60116-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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103
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Circumsporozoite protein-specific K(d)-restricted CD8+ T cells mediate protective antimalaria immunity in sporozoite-immunized MHC-I-K(d) transgenic mice. Mediators Inflamm 2014; 2014:728939. [PMID: 25132735 PMCID: PMC4124204 DOI: 10.1155/2014/728939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 06/23/2014] [Indexed: 11/28/2022] Open
Abstract
Although the roles of CD8+ T cells and a major preerythrocytic antigen, the circumsporozoite (CS) protein, in contributing protective antimalaria immunity induced by radiation-attenuated sporozoites, have been shown by a number of studies, the extent to which these players contribute to antimalaria immunity is still unknown. To address this question, we have generated C57BL/6 (B6) transgenic (Tg) mice, expressing Kd molecules under the MHC-I promoter, called MHC-I-Kd-Tg mice. In this study, we first determined that a single immunizing dose of IrPySpz induced a significant level of antimalaria protective immunity in MHC-I-Kd-Tg mice but not in B6 mice. Then, by depleting various T-cell subsets in vivo, we determined that CD8+ T cells are the main mediator of the protective immunity induced by IrPySpz. Furthermore, when we immunized (MHC-I-Kd-Tg × CS-Tg) F1 mice with IrPySpz after crossing MHC-I-Kd-Tg mice with PyCS-transgenic mice (CS-Tg), which are unable to mount PyCS-specific immunity, we found that IrPySpz immunization failed to induce protective antimalaria immunity in (MHC-I-Kd-Tg × CS-Tg) F1 mice, thus indicating the absence of PyCS antigen-dependent immunity in these mice. These results indicate that protective antimalaria immunity induced by IrPySpz in MHC-I-Kd-Tg mice is mediated by CS protein-specific, Kd-restricted CD8+ T cells.
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104
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Kapelski S, Klockenbring T, Fischer R, Barth S, Fendel R. Assessment of the neutrophilic antibody-dependent respiratory burst (ADRB) response to Plasmodium falciparum. J Leukoc Biol 2014; 96:1131-42. [PMID: 25118179 DOI: 10.1189/jlb.4a0614-283rr] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Semi-immunity against Pf malaria is based on a combination of cellular and humoral immune responses. PMNs and IgGs are considered important components of this process, but the underlying mechanisms are unclear. We investigated the neutrophilic ADRB by analyzing the production of ROS in response to Pf antigen-specific IgGs bound to solid-phase immobilized antigens (sADRB) or whole merozoites (mADRB). We found that the PMN stimulations in each assay were based on different underlying mechanisms, demonstrating the importance of the assay set-up for the evaluation of antibody-triggered PMN responses. In the sADRB assay, ROS were produced externally, and by specific blocking of CD32(a)/FcγRII(a), the immediate neutrophilic response was abolished, whereas the removal of CD16(b)/FcγRIII(b) had no substantial effect. The key role of CD32(a) was confirmed using CD16(b)-deficient PMNs, in which similar changes of neutrophilic ADRB profiles were recorded after treatment. In the mADRB assay, ROS were produced almost exclusively within the cell, suggesting that the underlying mechanism was phagocytosis. This was confirmed using an additional phagocytosis assay, in which PMNs specifically ingested merozoites opsonized with Ghanaian plasma IgGs, seven times more often than merozoites opsonized with European plasma IgGs (P<0.001). Our data show that assay set-ups used to evaluate the responses of PMNs and perhaps other effector cells must be chosen carefully to evaluate the appropriate cellular responses. Our robust, stable, and well-characterized methods could therefore be useful in malaria vaccine studies to analyze the antimalarial effector function of antibodies.
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Affiliation(s)
- Stephanie Kapelski
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and
| | - Torsten Klockenbring
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and
| | - Stefan Barth
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Institute for Applied Medical Engineering at Rheinisch-Westfälische Technische Hochschule Aachen University and Hospital, Department of Experimental Medicine and Immunotherapy, Aachen, Germany
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and
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105
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Florin-Christensen M, Suarez CE, Rodriguez AE, Flores DA, Schnittger L. Vaccines against bovine babesiosis: where we are now and possible roads ahead. Parasitology 2014; 141:1-30. [PMID: 25068315 DOI: 10.1017/s0031182014000961] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SUMMARY Bovine babesiosis caused by the tick-transmitted haemoprotozoans Babesia bovis, Babesia bigemina and Babesia divergens commonly results in substantial cattle morbidity and mortality in vast world areas. Although existing live vaccines confer protection, they have considerable disadvantages. Therefore, particularly in countries where large numbers of cattle are at risk, important research is directed towards improved vaccination strategies. Here a comprehensive overview of currently used live vaccines and of the status quo of experimental vaccine trials is presented. In addition, pertinent research fields potentially contributing to the development of novel non-live and/or live vaccines are discussed, including parasite antigens involved in host cell invasion and in pathogen-tick interactions, as well as the protective immunity against infection. The mining of available parasite genomes is continuously enlarging the array of potential vaccine candidates and, additionally, the recent development of a transfection tool for Babesia can significantly contribute to vaccine design. However, the complication and high cost of vaccination trials hinder Babesia vaccine research, and have so far seriously limited the systematic examination of antigen candidates and prevented an in-depth testing of formulations using different immunomodulators and antigen delivery systems.
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Affiliation(s)
| | - Carlos E Suarez
- Department of Veterinary Microbiology and Pathology,Washington State University,Pullman, WA 99164-7040,USA
| | - Anabel E Rodriguez
- Instituto de Patobiologia,CICVyA, INTA-Castelar, 1686 Hurlingham,Argentina
| | - Daniela A Flores
- Instituto de Patobiologia,CICVyA, INTA-Castelar, 1686 Hurlingham,Argentina
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106
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Claudia F. Malaria vaccine–is it still required? Are vaccine alternatives enough to achieve malaria control? Asian Pac J Trop Biomed 2014. [DOI: 10.12980/apjtb.4.2014apjtb-2014-0181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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107
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Bijker EM, Teirlinck AC, Schats R, van Gemert GJ, van de Vegte-Bolmer M, van Lieshout L, IntHout J, Hermsen CC, Scholzen A, Visser LG, Sauerwein RW. Cytotoxic markers associate with protection against malaria in human volunteers immunized with Plasmodium falciparum sporozoites. J Infect Dis 2014; 210:1605-15. [PMID: 24872326 PMCID: PMC4208622 DOI: 10.1093/infdis/jiu293] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Immunization of healthy volunteers by bites from Plasmodium falciparum-infected mosquitoes during chloroquine chemoprophylaxis (hereafter, chemoprophylaxis and sporozoites [CPS] immunization) induces sterile protection against malaria. CPS-induced protection is mediated by immunity against pre-erythrocytic stages, presumably at least partially by cytotoxic cellular responses. We therefore aimed to investigate the association of CPS-induced cytotoxic T-cell markers with protection. METHODS In a double-blind randomized controlled trial, we performed dose titration of CPS immunization followed by homologous challenge infection in 29 subjects. Immune responses were assessed by in vitro restimulation of peripheral blood mononuclear cells and flow cytometry. RESULTS Dose-dependent complete protection was obtained in 4 of 5 volunteers after immunization with bites from 45 P. falciparum-infected mosquitoes, in 8 of 9 volunteers with bites from 30, and in 5 of 10 volunteers with bites from 15 (odds ratio [OR], 5.0; 95% confidence interval [CI], 1.5-17). Completely protected subjects had significantly higher proportions of CD4 T cells expressing the degranulation marker CD107a (OR, 8.4; 95% CI, 1.5-123; P = .011) and CD8 cells producing granzyme B (OR, 11; 95% CI, 1.9-212; P = .004) after P. falciparum restimulation. CONCLUSIONS These data underline the efficiency of CPS immunization to induce sterile protection and support a possible role for cytotoxic CD4 and CD8 T-cell responses in pre-erythrocytic immunity. CLINICAL TRIALS REGISTRATION NCT01218893.
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Affiliation(s)
| | | | | | | | | | - Lisette van Lieshout
- Department of Medical Microbiology, Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Joanna IntHout
- Department for Health Evidence, Section Biostatistics, Radboud university medical center, Nijmegen
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108
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Abstract
Malaria is a life-threatening disease caused by parasites of the Plasmodium genus. In many parts of the world, the parasites have developed resistance to a number of antimalarial agents. Key interventions to control malaria include prompt and effective treatment with artemisinin-based combination therapies, use of insecticidal nets by individuals at risk and active research into malaria vaccines. Protection against malaria through vaccination was demonstrated more than 30 years ago when individuals were vaccinated via repeated bites by Plasmodium falciparum-infected and irradiated but still metabolically active mosquitoes. However, vaccination with high doses of irradiated sporozoites injected into humans has long been considered impractical. Yet, following recent success using whole-organism vaccines, the approach has received renewed interest; it was recently reported that repeated injections of irradiated sporozoites increased protection in 80 vaccinated individuals. Other approaches include subunit malaria vaccines, such as the current leading candidate RTS,S (consisting of fusion between a portion of the P. falciparum-derived circumsporozoite protein and the hepatitis B surface antigen), which has been demonstrated to induce reasonably good protection. Although results have been encouraging, the level of protection is generally considered to be too low to achieve eradication of malaria. There is great interest in developing new and better formulations and stable delivery systems to improve immunogenicity. In this review, we will discuss recent strategies to develop efficient malaria vaccines.
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Affiliation(s)
- C Arama
- Malaria Research and Training Center, University of Sciences Techniques and Technologies of Bamako (USTTB), Bamako, Mali; Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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109
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Shepherd SM, Shoff WH. Vaccination for the expatriate and long-term traveler. Expert Rev Vaccines 2014; 13:775-800. [DOI: 10.1586/14760584.2014.913485] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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110
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Brando C, Richardson JH, Murphy J, Ockenhouse CF, Kamau E. Phenotypic characterization of Plasmodium berghei responsive CD8+ T cells after immunization with live sporozoites under chloroquine cover. Malar J 2014; 13:92. [PMID: 24620841 PMCID: PMC4008132 DOI: 10.1186/1475-2875-13-92] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 02/02/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND An effective malaria vaccine remains elusive. The most effective experimental vaccines confer only limited and short-lived protection despite production of protective antibodies. However, immunization with irradiated sporozoites, or with live sporozoites under chloroquine cover, has resulted in long-term protection apparently due to the generation of protective CD8+ T cells. The nature and function of these protective CD8+ T cells has not been elucidated. In the current study, the phenotype of CD8+ T cells generated after immunization of C57BL/6 mice with live Plasmodium berghei sporozoites under chloroquine cover was investigated. METHODS Female C57BL/6 mice, C57BL/6 mice B2 macroglobulin -/- [KO], or invariant chain-/- [Ic KO] [6-8 weeks old] were immunized with P. berghei sporozoites and treated daily with 800 μg/mouse of chloroquine for nine days. This procedure of immunization is referred to as "infection/cure". Mice were challenged by inoculating intravenously 1,000 infectious sporozoites. Appearance of parasitaemia was monitored by Giemsa-stained blood smears. RESULTS By use of MHC I and MHC II deficient animals, results indicate that CD8+ T cells are necessary for full protection and that production of protective antibodies is either CD4+ T helper cells dependent and/or lymphokines produced by CD4 cells contribute to the protection directly or by helping CD8+ T cells. Further, the phenotype of infection/cure P. berghei responsive CD8+ T cells was determined to be KLRG1high CD27low CD44high and CD62Llow. CONCLUSION The KLRG1high CD27low CD44high and CD62Llow phenotype of CD8+ T cells is associated with protection and should be investigated further as a candidate correlate of protection.
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Affiliation(s)
| | | | | | | | - Edwin Kamau
- Military Malaria Research Program, Malaria Vaccine Branch, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD 20910, USA.
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111
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Cowan GJM, Bockau U, Eleni-Muus J, Aldag I, Samuel K, Creasey AM, Hartmann MWW, Cavanagh DR. A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila. PLoS One 2014; 9:e87198. [PMID: 24489871 PMCID: PMC3906136 DOI: 10.1371/journal.pone.0087198] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 12/20/2013] [Indexed: 01/15/2023] Open
Abstract
Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens.
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Affiliation(s)
- Graeme J. M. Cowan
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | | | - Kay Samuel
- Cell Therapy Group, Scottish National Blood Transfusion Service, Edinburgh, United Kingdom
| | - Alison M. Creasey
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | - David R. Cavanagh
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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112
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Daubenberger CA. First clinical trial of purified, irradiated malaria sporozoites in humans. Expert Rev Vaccines 2014; 11:31-3. [DOI: 10.1586/erv.11.161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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113
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Geels MJ, Imoukhuede EB, Imbault N, van Schooten H, McWade T, Troye-Blomberg M, Dobbelaer R, Craig AG, Leroy O. European Vaccine Initiative: lessons from developing malaria vaccines. Expert Rev Vaccines 2014; 10:1697-708. [DOI: 10.1586/erv.11.158] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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114
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Medeiros MM, Fotoran WL, dalla Martha RC, Katsuragawa TH, Pereira da Silva LH, Wunderlich G. Natural antibody response to Plasmodium falciparum merozoite antigens MSP5, MSP9 and EBA175 is associated to clinical protection in the Brazilian Amazon. BMC Infect Dis 2013; 13:608. [PMID: 24373342 PMCID: PMC3880555 DOI: 10.1186/1471-2334-13-608] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/23/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Antibodies have an essential role in the acquired immune response against blood stage P. falciparum infection. Although several antigens have been identified as important antibody targets, it is still elusive which antigens have to be recognized for clinical protection. Herein, we analyzed antibodies from plasmas from symptomatic or asymptomatic individuals living in the same geographic area in the Western Amazon, measuring their recognition of multiple merozoite antigens. METHODS Specific fragments of genes encoding merozoite proteins AMA1 and members of MSP and EBL families from circulating P. falciparum field isolates present in asymptomatic and symptomatic patients were amplified by PCR. After cloning and expression of different versions of the antigens as recombinant GST-fusion peptides, we tested the reactivity of patients' plasmas by ELISA and the presence of IgG subclasses in the most reactive plasmas. RESULTS 11 out of 24 recombinant antigens were recognized by plasmas from either symptomatic or asymptomatic infections. Antibodies to MSP9 (X2(DF=1) = 9.26/p = 0.0047) and MSP5 (X2(DF=1) = 8.29/p = 0.0069) were more prevalent in asymptomatic individuals whereas the opposite was observed for MSP1 block 2-MAD20 (X2(DF=1) = 6.41/p = 0.0206, Fisher's exact test). Plasmas from asymptomatic individuals reacted more intensely against MSP4 (U = 210.5, p < 0.03), MSP5 (U = 212, p < 0.004), MSP9 (U = 189.5, p < 0.002) and EBA175 (U = 197, p < 0.014, Mann-Whitney's U test). IgG1 and IgG3 were predominant for all antigens, but some patients also presented with IgG2 and IgG4. The recognition of MSP5 (OR = 0.112, IC95% = 0.021-0.585) and MSP9 (OR = 0.125, IC95% = 0.030-0.529, cross tab analysis) predicted 8.9 and 8 times less chances, respectively, to present symptoms. Higher antibody levels against MSP5 and EBA175 were associated by odds ratios of 9.4 (IC95% = 1.29-69.25) and 5.7 (IC95% = 1.12-29.62, logistic regression), respectively, with an asymptomatic status. CONCLUSIONS Merozoite antigens were targets of cytophilic antibodies and antibodies against MSP5, MSP9 and EBA175 were independently associated with decreased symptoms.
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Affiliation(s)
| | | | | | | | | | - Gerhard Wunderlich
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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115
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Dutta S, Dlugosz LS, Drew DR, Ge X, Ababacar D, Rovira YI, Moch JK, Shi M, Long CA, Foley M, Beeson JG, Anders RF, Miura K, Haynes JD, Batchelor AH. Overcoming antigenic diversity by enhancing the immunogenicity of conserved epitopes on the malaria vaccine candidate apical membrane antigen-1. PLoS Pathog 2013; 9:e1003840. [PMID: 24385910 PMCID: PMC3873463 DOI: 10.1371/journal.ppat.1003840] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 11/04/2013] [Indexed: 12/16/2022] Open
Abstract
Malaria vaccine candidate Apical Membrane Antigen-1 (AMA1) induces protection, but only against parasite strains that are closely related to the vaccine. Overcoming the AMA1 diversity problem will require an understanding of the structural basis of cross-strain invasion inhibition. A vaccine containing four diverse allelic proteins 3D7, FVO, HB3 and W2mef (AMA1 Quadvax or QV) elicited polyclonal rabbit antibodies that similarly inhibited the invasion of four vaccine and 22 non-vaccine strains of P. falciparum. Comparing polyclonal anti-QV with antibodies against a strain-specific, monovalent, 3D7 AMA1 vaccine revealed that QV induced higher levels of broadly inhibitory antibodies which were associated with increased conserved face and domain-3 responses and reduced domain-2 response. Inhibitory monoclonal antibodies (mAb) raised against the QV reacted with a novel cross-reactive epitope at the rim of the hydrophobic trough on domain-1; this epitope mapped to the conserved face of AMA1 and it encompassed the 1e-loop. MAbs binding to the 1e-loop region (1B10, 4E8 and 4E11) were ∼10-fold more potent than previously characterized AMA1-inhibitory mAbs and a mode of action of these 1e-loop mAbs was the inhibition of AMA1 binding to its ligand RON2. Unlike the epitope of a previously characterized 3D7-specific mAb, 1F9, the 1e-loop inhibitory epitope was partially conserved across strains. Another novel mAb, 1E10, which bound to domain-3, was broadly inhibitory and it blocked the proteolytic processing of AMA1. By itself mAb 1E10 was weakly inhibitory but it synergized with a previously characterized, strain-transcending mAb, 4G2, which binds close to the hydrophobic trough on the conserved face and inhibits RON2 binding to AMA1. Novel inhibition susceptible regions and epitopes, identified here, can form the basis for improving the antigenic breadth and inhibitory response of AMA1 vaccines. Vaccination with a few diverse antigenic proteins could provide universal coverage by redirecting the immune response towards conserved epitopes. Numerous reports of vaccine failure are attributed to a mismatch between the genotype of the vaccine and the circulating target strains. This observation is congruent to the view that polyvalent vaccines protect broadly by inducing a multitude of type-specific antibodies. Polyvalent vaccines that can overcome antigenic diversity by refocusing antibody responses towards conserved functional epitopes are highly desirable. Development of an Apical Membrane Antigen-1 (AMA1) malaria vaccine has been impeded by extreme antigenic diversity in the field. We present here a solution to the AMA1 diversity problem. Antibodies against a mixture of only four naturally occurring AMA1 allelic proteins “Quadvax” inhibited invasion of red blood cells by a diverse panel of malaria parasites that represented the global diversity of AMA1 in the field. Competition experiments suggested that in addition to improving the diversity of strain-specific antibodies, the mechanism of broadened inhibition involved an increase in responses against conserved inhibitory epitopes. Monoclonal antibodies against the Quadvax inhibited invasion either by blocking the binding of AMA1 to its receptor RON2 or by blocking a crucial proteolytic processing event. Some mixtures of these antibodies were much more effective than expected and were shown to act synergistically. Together these two classes of functional invasion inhibitory epitopes can be targeted to engineer a more potent AMA1 vaccine.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antigenic Variation/genetics
- Antigenic Variation/immunology
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Cells, Cultured
- Conserved Sequence/immunology
- Epitope Mapping
- Epitopes/genetics
- Epitopes/immunology
- Immunity, Humoral
- Malaria Vaccines/chemistry
- Malaria Vaccines/immunology
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/immunology
- Mice
- Mice, Nude
- Models, Molecular
- Plasmodium berghei/genetics
- Plasmodium berghei/immunology
- Plasmodium falciparum/immunology
- Protein Structure, Tertiary
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Rabbits
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/immunology
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Affiliation(s)
- Sheetij Dutta
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- * E-mail:
| | - Lisa S. Dlugosz
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | | | - Xiopeng Ge
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Diouf Ababacar
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yazmin I. Rovira
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - J. Kathleen Moch
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Meng Shi
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Michael Foley
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | | | - Robin F. Anders
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - J. David Haynes
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Adrian H. Batchelor
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
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116
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Model for in vivo assessment of humoral protection against malaria sporozoite challenge by passive transfer of monoclonal antibodies and immune serum. Infect Immun 2013; 82:808-17. [PMID: 24478094 DOI: 10.1128/iai.01249-13] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Evidence from clinical trials of malaria vaccine candidates suggests that both cell-mediated and humoral immunity to pre-erythrocytic parasite stages can provide protection against infection. Novel pre-erythrocytic antibody (Ab) targets could be key to improving vaccine formulations, which are currently based on targeting antigens such as the circumsporozoite protein (CSP). However, methods to assess the effects of sporozoite-specific Abs on pre-erythrocytic infection in vivo remain underdeveloped. Here, we combined passive transfer of monoclonal Abs (MAbs) or immune serum with a luciferase-expressing Plasmodium yoelii sporozoite challenge to assess Ab-mediated inhibition of liver infection in mice. Passive transfer of a P. yoelii CSP MAb showed inhibition of liver infection when mice were challenged with sporozoites either intravenously or by infectious mosquito bite. However, inhibition was most potent for the mosquito bite challenge, leading to a more significant reduction of liver-stage burden and even a lack of progression to blood-stage parasitemia. This suggests that Abs provide effective protection against a natural infection. Inhibition of liver infection was also achieved by passive transfer of immune serum from whole-parasite-immunized mice. Furthermore, we demonstrated that passive transfer of a MAb against P. falciparum CSP inhibited liver-stage infection in a humanized mouse/P. falciparum challenge model. Together, these models constitute unique and sensitive in vivo methods to assess serum-transferable protection against Plasmodium sporozoite challenge.
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Feller T, Thom P, Koch N, Spiegel H, Addai-Mensah O, Fischer R, Reimann A, Pradel G, Fendel R, Schillberg S, Scheuermayer M, Schinkel H. Plant-based production of recombinant Plasmodium surface protein pf38 and evaluation of its potential as a vaccine candidate. PLoS One 2013; 8:e79920. [PMID: 24278216 PMCID: PMC3836784 DOI: 10.1371/journal.pone.0079920] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 09/29/2013] [Indexed: 11/19/2022] Open
Abstract
Pf38 is a surface protein of the malarial parasite Plasmodium falciparum. In this study, we produced and purified recombinant Pf38 and a fusion protein composed of red fluorescent protein and Pf38 (RFP-Pf38) using a transient expression system in the plant Nicotiana benthamiana. To our knowledge, this is the first description of the production of recombinant Pf38. To verify the quality of the recombinant Pf38, plasma from semi-immune African donors was used to confirm specific binding to Pf38. ELISA measurements revealed that immune responses to Pf38 in this African subset were comparable to reactivities to AMA-1 and MSP119. Pf38 and RFP-Pf38 were successfully used to immunise mice, although titres from these mice were low (on average 1∶11.000 and 1∶39.000, respectively). In immune fluorescence assays, the purified IgG fraction from the sera of immunised mice recognised Pf38 on the surface of schizonts, gametocytes, macrogametes and zygotes, but not sporozoites. Growth inhibition assays using αPf38 antibodies demonstrated strong inhibition (≥60%) of the growth of blood-stage P. falciparum. The development of zygotes was also effectively inhibited by αPf38 antibodies, as determined by the zygote development assay. Collectively, these results suggest that Pf38 is an interesting candidate for the development of a malaria vaccine.
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Affiliation(s)
- Tatjana Feller
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
| | - Pascal Thom
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
| | - Natalie Koch
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
| | - Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
| | | | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
- RWTH Aachen University, Institute for Molecular Biotechnology, Aachen, Germany
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
| | - Gabriele Pradel
- RWTH Aachen University, Institute for Molecular Biotechnology, Aachen, Germany
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
- RWTH Aachen University, Institute for Molecular Biotechnology, Aachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
| | - Matthias Scheuermayer
- Research Center for Infectious Diseases, University of Wuerzburg, Wuerzburg, Germany
| | - Helga Schinkel
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany
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118
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Padte NN, Boente-Carrera M, Andrews CD, McManus J, Grasperge BF, Gettie A, Coelho-dos-Reis JG, Li X, Wu D, Bruder JT, Sedegah M, Patterson N, Richie TL, Wong CH, Ho DD, Vasan S, Tsuji M. A glycolipid adjuvant, 7DW8-5, enhances CD8+ T cell responses induced by an adenovirus-vectored malaria vaccine in non-human primates. PLoS One 2013; 8:e78407. [PMID: 24205224 PMCID: PMC3808339 DOI: 10.1371/journal.pone.0078407] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/11/2013] [Indexed: 01/12/2023] Open
Abstract
A key strategy to a successful vaccine against malaria is to identify and develop new adjuvants that can enhance T-cell responses and improve protective immunity. Upon co-administration with a rodent malaria vaccine in mice, 7DW8-5, a recently identified novel analog of α-galactosylceramide (α-GalCer), enhances the level of malaria-specific protective immune responses more strongly than the parent compound. In this study, we sought to determine whether 7DW8-5 could provide a similar potent adjuvant effect on a candidate human malaria vaccine in the more relevant non-human primate (NHP) model, prior to committing to clinical development. The candidate human malaria vaccine, AdPfCA (NMRC-M3V-Ad-PfCA), consists of two non-replicating recombinant adenoviral (Ad) vectors, one expressing the circumsporozoite protein (CSP) and another expressing the apical membrane antigen-1 (AMA1) of Plasmodium falciparum. In several phase 1 clinical trials, AdPfCA was well tolerated and demonstrated immunogenicity for both humoral and cell-mediated responses. In the study described herein, 25 rhesus macaques received prime and boost intramuscular (IM) immunizations of AdPfCA alone or with an ascending dose of 7DW8-5. Our results indicate that 7DW8-5 is safe and well-tolerated and provides a significant enhancement (up to 9-fold) in malaria-specific CD8+ T-cell responses after both priming and boosting phases, supporting further clinical development.
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Affiliation(s)
- Neal N. Padte
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
| | - Mar Boente-Carrera
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
| | - Chasity D. Andrews
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
| | - Jenny McManus
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
| | - Brooke F. Grasperge
- Tulane National Primate Research Center, Tulane University Medical Center, Covington, Louisiana, United States of America
| | - Agegnehu Gettie
- Tulane National Primate Research Center, Tulane University Medical Center, Covington, Louisiana, United States of America
| | - Jordana G. Coelho-dos-Reis
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
| | - Xiangming Li
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
| | - Douglass Wu
- Department of Chemistry, the Scripps Research Institute, La Jolla, California, United States of America
| | - Joseph T. Bruder
- Research, GenVec, Inc., Gaithersburg, Maryland, United States of America
| | - Martha Sedegah
- US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Noelle Patterson
- US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, Maryland, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, United States of America
| | - Thomas L. Richie
- US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Chi-Huey Wong
- Department of Chemistry, the Scripps Research Institute, La Jolla, California, United States of America
| | - David D. Ho
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
| | - Sandhya Vasan
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
- * E-mail: (SV); (MT)
| | - Moriya Tsuji
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, New York, United States of America
- * E-mail: (SV); (MT)
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Ma J, Trop S, Baer S, Rakhmanaliev E, Arany Z, Dumoulin P, Zhang H, Romano J, Coppens I, Levitsky V, Levitskaya J. Dynamics of the major histocompatibility complex class I processing and presentation pathway in the course of malaria parasite development in human hepatocytes: implications for vaccine development. PLoS One 2013; 8:e75321. [PMID: 24086507 PMCID: PMC3783408 DOI: 10.1371/journal.pone.0075321] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/12/2013] [Indexed: 12/15/2022] Open
Abstract
Control of parasite replication exerted by MHC class I restricted CD8+ T-cells in the liver is critical for vaccination-induced protection against malaria. While many intracellular pathogens subvert the MHC class I presentation machinery, its functionality in the course of malaria replication in hepatocytes has not been characterized. Using experimental systems based on specific identification, isolation and analysis of human hepatocytes infected with P. berghei ANKA GFP or P. falciparum 3D7 GFP sporozoites we demonstrated that molecular components of the MHC class I pathway exhibit largely unaltered expression in malaria-infected hepatocytes until very late stages of parasite development. Furthermore, infected cells showed no obvious defects in their capacity to upregulate expression of different molecular components of the MHC class I machinery in response to pro-inflammatory lymphokines or trigger direct activation of allo-specific or peptide-specific human CD8+ T-cells. We further demonstrate that ectopic expression of circumsporozoite protein does not alter expression of critical genes of the MHC class I pathway and its response to pro-inflammatory cytokines. In addition, we identified supra-cellular structures, which arose at late stages of parasite replication, possessed the characteristic morphology of merosomes and exhibited nearly complete loss of surface MHC class I expression. These data have multiple implications for our understanding of natural T-cell immunity against malaria and may promote development of novel, efficient anti-malaria vaccines overcoming immune escape of the parasite in the liver.
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Affiliation(s)
- Jinxia Ma
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Stefanie Trop
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Samantha Baer
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Elian Rakhmanaliev
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Zita Arany
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Peter Dumoulin
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Hao Zhang
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Julia Romano
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Isabelle Coppens
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Victor Levitsky
- Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jelena Levitskaya
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
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Wanaguru M, Crosnier C, Johnson S, Rayner JC, Wright GJ. Biochemical analysis of the Plasmodium falciparum erythrocyte-binding antigen-175 (EBA175)-glycophorin-A interaction: implications for vaccine design. J Biol Chem 2013; 288:32106-32117. [PMID: 24043627 PMCID: PMC3820850 DOI: 10.1074/jbc.m113.484840] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PfEBA175 has an important role in the invasion of human erythrocytes by Plasmodium falciparum and is therefore considered a high priority blood-stage malaria vaccine candidate. PfEBA175 mediates adhesion to erythrocytes through binding of the Duffy-binding-like (DBL) domains in its extracellular domain to Neu5Acα2–3Gal displayed on the O-linked glycans of glycophorin-A (GYPA). Because of the difficulties in expressing active full-length (FL) P. falciparum proteins in a recombinant form, previous analyses of the PfEBA175-GYPA interaction have largely focused on the DBL domains alone, and therefore they have not been performed in the context of the native protein sequence. Here, we express the entire ectodomain of PfEBA175 (PfEBA175 FL) in soluble form, allowing us to compare the biochemical and immunological properties with a fragment containing only the tandem DBL domains (“region II,” PfEBA175 RII). Recombinant PfEBA175 FL bound human erythrocytes in a trypsin and neuraminidase-sensitive manner and recognized Neu5Acα2–3Gal-containing glycans, confirming its biochemical activity. A quantitative binding analysis showed that PfEBA175 FL interacted with native GYPA with a KD ∼0.26 μm and is capable of self-association. By comparison, the RII fragment alone bound GYPA with a lower affinity demonstrating that regions outside of the DBL domains are important for interactions with GYPA; antibodies directed to these other regions also contributed to the inhibition of parasite invasion. These data demonstrate the importance of PfEBA175 regions other than the DBL domains in the interaction with GYPA and merit their inclusion in an EBA175-based vaccine.
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Affiliation(s)
- Madushi Wanaguru
- From the Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH,; the Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA
| | - Cécile Crosnier
- From the Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH,; the Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA
| | - Steven Johnson
- the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Julian C Rayner
- the Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA
| | - Gavin J Wright
- From the Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH,; the Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA.
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121
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RALP1 is a rhoptry neck erythrocyte-binding protein of Plasmodium falciparum merozoites and a potential blood-stage vaccine candidate antigen. Infect Immun 2013; 81:4290-8. [PMID: 24002067 DOI: 10.1128/iai.00690-13] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Erythrocyte invasion by merozoites is an obligatory stage of Plasmodium infection and is essential to disease progression. Proteins in the apical organelles of merozoites mediate the invasion of erythrocytes and are potential malaria vaccine candidates. Rhoptry-associated, leucine zipper-like protein 1 (RALP1) of Plasmodium falciparum was previously found to be specifically expressed in schizont stages and localized to the rhoptries of merozoites by immunofluorescence assay (IFA). Also, RALP1 has been refractory to gene knockout attempts, suggesting that it is essential for blood-stage parasite survival. These characteristics suggest that RALP1 can be a potential blood-stage vaccine candidate antigen, and here we assessed its potential in this regard. Antibodies were raised against recombinant RALP1 proteins synthesized by using the wheat germ cell-free system. Immunoelectron microscopy demonstrated for the first time that RALP1 is a rhoptry neck protein of merozoites. Moreover, our IFA data showed that RALP1 translocates from the rhoptry neck to the moving junction during merozoite invasion. Growth and invasion inhibition assays revealed that anti-RALP1 antibodies inhibit the invasion of erythrocytes by merozoites. The findings that RALP1 possesses an erythrocyte-binding epitope in the C-terminal region and that anti-RALP1 antibodies disrupt tight-junction formation, are evidence that RALP1 plays an important role during merozoite invasion of erythrocytes. In addition, human sera collected from areas in Thailand and Mali where malaria is endemic recognized this protein. Overall, our findings indicate that RALP1 is a rhoptry neck erythrocyte-binding protein and that it qualifies as a potential blood-stage vaccine candidate.
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122
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Roose K, De Baets S, Schepens B, Saelens X. Hepatitis B core-based virus-like particles to present heterologous epitopes. Expert Rev Vaccines 2013; 12:183-98. [PMID: 23414409 DOI: 10.1586/erv.12.150] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Since the first effort to recombinantly express the hepatitis B core protein (HBc) in bacteria, the remarkable virion-like structure has fuelled interest in unraveling the structural and antigenic properties of this protein. Initial studies proved HBc virus-like particles to possess strong immunogenic properties, which can be conveyed to linked antigens. More than 35 years later, numerous studies have been performed using HBc as a carrier protein for antigens derived from over a dozen different pathogens and diseases. In this review, the authors highlight the intriguing features of HBc as carrier and antigen, illustrated by some examples and experimental results that underscore the value of HBc as an antigen-presenting platform. Two of these HBc fusions, targeting influenza A and malaria, have even progressed into clinical testing. In the future, the HBc-based virus-like particles platform will probably continue to be used for the display of poorly immunogenic antigens, mainly because virus-like particle formation by HBc capsomers is compatible with nearly any available recombinant gene expression system.
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Affiliation(s)
- Kenny Roose
- Department for Molecular Biomedical Research, VIB, 9052 Ghent, Belgium
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123
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Protective efficacy of baculovirus dual expression system vaccine expressing Plasmodium falciparum circumsporozoite protein. PLoS One 2013; 8:e70819. [PMID: 23951015 PMCID: PMC3741388 DOI: 10.1371/journal.pone.0070819] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 06/22/2013] [Indexed: 12/31/2022] Open
Abstract
We have previously developed a new malaria vaccine delivery system based on the baculovirus dual expression system (BDES). In this system, expression of malaria antigens is driven by a dual promoter consisting of the baculovirus-derived polyhedrin and mammal-derived cytomegalovirus promoters. To test this system for its potential as a vaccine against human malaria parasites, we investigated immune responses against the newly developed BDES-based Plasmodium falciparum circumsporozoite protein vaccines (BDES-PfCSP) in mice and Rhesus monkeys. Immunization of mice with BDES-PfCSP induced Th1/Th2-mixed type immune responses with high PfCSP-specific antibody (Ab) titers, and provided significant protection against challenge from the bites of mosquitoes infected with a transgenic P. berghei line expressing PfCSP. Next, we evaluated the immunogenicity of the BDES-PfCSP vaccine in a rhesus monkey model. Immunization of BDES-PfCSP elicited high levels of anti-PfCSP Ab responses in individual monkeys. Moreover, the sera from the immunized monkeys remarkably blocked sporozoite invasion of HepG2 cells. Taken together with two animal models, our results indicate that this novel vaccine platform (BDES) has potential clinical application as a vaccine against malaria.
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124
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Good MF, Reiman JM, Rodriguez IB, Ito K, Yanow SK, El-Deeb IM, Batzloff MR, Stanisic DI, Engwerda C, Spithill T, Hoffman SL, Lee M, McPhun V. Cross-species malaria immunity induced by chemically attenuated parasites. J Clin Invest 2013; 123:66634. [PMID: 23863622 PMCID: PMC4011145 DOI: 10.1172/jci66634] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 04/26/2013] [Indexed: 01/29/2023] Open
Abstract
Vaccine development for the blood stages of malaria has focused on the induction of antibodies to parasite surface antigens, most of which are highly polymorphic. An alternate strategy has evolved from observations that low-density infections can induce antibody-independent immunity to different strains. To test this strategy, we treated parasitized red blood cells from the rodent parasite Plasmodium chabaudi with seco-cyclopropyl pyrrolo indole analogs. These drugs irreversibly alkylate parasite DNA, blocking their ability to replicate. After administration in mice, DNA from the vaccine could be detected in the blood for over 110 days and a single vaccination induced profound immunity to different malaria parasite species. Immunity was mediated by CD4+ T cells and was dependent on the red blood cell membrane remaining intact. The human parasite, Plasmodium falciparum, could also be attenuated by treatment with seco-cyclopropyl pyrrolo indole analogs. These data demonstrate that vaccination with chemically attenuated parasites induces protective immunity and provide a compelling rationale for testing a blood-stage parasite-based vaccine targeting human Plasmodium species.
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125
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Sheehy SH, Douglas AD, Draper SJ. Challenges of assessing the clinical efficacy of asexual blood-stage Plasmodium falciparum malaria vaccines. Hum Vaccin Immunother 2013; 9:1831-40. [PMID: 23778312 PMCID: PMC3906345 DOI: 10.4161/hv.25383] [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] [Indexed: 12/22/2022] Open
Abstract
In the absence of any highly effective vaccine candidate against Plasmodium falciparum malaria, it remains imperative for the field to pursue all avenues that may lead to the successful development of such a formulation. The development of a subunit vaccine targeting the asexual blood-stage of Plasmodium falciparum malaria infection has proven particularly challenging with only limited success to date in clinical trials. However, only a fraction of potential blood-stage vaccine antigens have been evaluated as targets, and a number of new promising candidate antigen formulations and delivery platforms are approaching clinical development. It is therefore essential that reliable and sensitive methods of detecting, or ruling out, even modest efficacy of blood-stage vaccines in small clinical trials be established. In this article we evaluate the challenges facing blood-stage vaccine developers, assess the appropriateness and limitations of various in vivo approaches for efficacy assessment and suggest future directions for the field.
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126
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Acquired antibodies to merozoite antigens in children from Uganda with uncomplicated or severe Plasmodium falciparum malaria. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1170-80. [PMID: 23740926 DOI: 10.1128/cvi.00156-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Malaria can present itself as an uncomplicated or severe disease. We have here studied the quantity and quality of antibody responses against merozoite antigens, as well as multiplicity of infection (MOI), in children from Uganda. We found higher levels of IgG antibodies toward erythrocyte-binding antigen EBA181, MSP2 of Plasmodium falciparum 3D7 and FC27 (MSP2-3D7/FC27), and apical membrane antigen 1 (AMA1) in patients with uncomplicated malaria by enzyme-linked immunosorbent assay (ELISA) but no differences against EBA140, EBA175, MSP1, and reticulocyte-binding protein homologues Rh2 and Rh4 or for IgM against MSP2-3D7/FC27.Patients with uncomplicated malaria were also shown to have higher antibody affinities for AMA1 by surface plasmon resonance (SPR). Decreased invasion of two clinical P. falciparum isolates in the presence of patient plasma correlated with lower initial parasitemia in the patients, in contrast to comparisons of parasitemia to ELISA values or antibody affinities, which did not show any correlations. Analysis of the heterogeneity of the infections revealed a higher MOI in patients with uncomplicated disease, with the P. falciparum K1 MSP1 (MSP1-K1) and MSP2-3D7 being the most discriminative allelic markers. Higher MOIs also correlated positively with higher antibody levels in several of the ELISAs. In conclusion, certain antibody responses and MOIs were associated with differences between uncomplicated and severe malaria. When different assays were combined, some antibodies, like those against AMA1, seemed particularly discriminative. However, only decreased invasion correlated with initial parasitemia in the patient, signaling the importance of functional assays in understanding development of immunity against malaria and in evaluating vaccine candidates.
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127
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Current status of malaria vaccines. Indian J Pediatr 2013; 80:441-3. [PMID: 23604615 DOI: 10.1007/s12098-013-1031-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 03/28/2013] [Indexed: 10/26/2022]
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128
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Zakeri S, Sadeghi H, Mehrizi AA, Djadid ND. Population genetic structure and polymorphism analysis of gene encoding apical membrane antigen-1 (AMA-1) of Iranian Plasmodium vivax wild isolates. Acta Trop 2013; 126:269-79. [PMID: 23467011 DOI: 10.1016/j.actatropica.2013.02.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 02/14/2013] [Accepted: 02/20/2013] [Indexed: 11/27/2022]
Abstract
Plasmodium vivax apical membrane antigen-1 (PvAMA-1) is a major candidate antigen for human malaria vaccine. In the present study, polymorphism of pvama-1 among Iranian isolates was investigated to generate useful information on this vaccine candidate antigen, which is required for the rational design of a vaccine against P. vivax. Blood samples were collected from P. vivax-infected Iranian patients during 2009-2010. Of 99 collected isolates, 37 were analyzed for almost the entire pvama-1 gene using sequencing. The overall nucleotide diversity (π) was 0.00826 ± 0.0004 and the majority of polymorphic sites were identified in domain I (DI) of the pvama-1 gene. Neutrality analysis using Tajima's D, Fu and Li's D* and F* and McDonald Kreitman tests showed a significant positive departure from neutral substitution patterns, indicating a possible balancing selection across the entire ectodomain and DI sequences of pvama-1 gene. However, no evidence was found for the balancing selection in DII and DIII regions of Iranian PvAMA-1. Also, 29 haplotypes with different frequencies were identified and the overall haplotype diversity was 0.982 ± 0.012. Epitope mapping prediction of PvAMA-1 showed the potential B-cell epitopes across DI-DIII overlap with E145K, P210S, R249H, G253E, K352E, R438H and N445D mutations; however, no mutation has been found in intrinsically unstructured/disordered regions. The fixation index (Fst) estimation between Iran and the closest geographical sites such as India (0.0707) showed a slight geographical genetic differentiation; however, the Fst estimation between Iran and Thailand (0.1253) suggested a moderate geographical isolation. In summary, genetic investigation in pvama-1 among Iranian P. vivax isolates indicates that this antigen showed limited antigenic diversity and most of the detected mutations are located outside B-cell epitopes. Therefore, the present results have significant implications in understanding the nature of P. vivax population circulating in Iran as well as in providing useful information for malaria vaccine development based on this antigen.
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Affiliation(s)
- Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran 1316943551, Iran.
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Palacpac NMQ, Ntege E, Yeka A, Balikagala B, Suzuki N, Shirai H, Yagi M, Ito K, Fukushima W, Hirota Y, Nsereko C, Okada T, Kanoi BN, Tetsutani K, Arisue N, Itagaki S, Tougan T, Ishii KJ, Ueda S, Egwang TG, Horii T. Phase 1b randomized trial and follow-up study in Uganda of the blood-stage malaria vaccine candidate BK-SE36. PLoS One 2013; 8:e64073. [PMID: 23724021 PMCID: PMC3665850 DOI: 10.1371/journal.pone.0064073] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 04/05/2013] [Indexed: 01/31/2023] Open
Abstract
Background Up to now a malaria vaccine remains elusive. The Plasmodium falciparum serine repeat antigen-5 formulated with aluminum hydroxyl gel (BK-SE36) is a blood-stage malaria vaccine candidate that has undergone phase 1a trial in malaria-naive Japanese adults. We have now assessed the safety and immunogenicity of BK-SE36 in a malaria endemic area in Northern Uganda. Methods We performed a two-stage, randomized, single-blinded, placebo-controlled phase 1b trial (Current Controlled trials ISRCTN71619711). A computer-generated sequence randomized healthy subjects for 2 subcutaneous injections at 21-day intervals in Stage1 (21–40 year-olds) to 1-mL BK-SE36 (BKSE1.0) (n = 36) or saline (n = 20) and in Stage2 (6–20 year-olds) to BKSE1.0 (n = 33), 0.5-mL BK-SE36 (BKSE0.5) (n = 33), or saline (n = 18). Subjects and laboratory personnel were blinded. Safety and antibody responses 21-days post-second vaccination (Day42) were assessed. Post-trial, to compare the risk of malaria episodes 130–365 days post-second vaccination, Stage2 subjects were age-matched to 50 control individuals. Results Nearly all subjects who received BK-SE36 had induration (Stage1, n = 33, 92%; Stage2, n = 63, 96%) as a local adverse event. No serious adverse event related to BK-SE36 was reported. Pre-existing anti-SE36 antibody titers negatively correlated with vaccination-induced antibody response. At Day42, change in antibody titers was significant for seronegative adults (1.95-fold higher than baseline [95% CI, 1.56–2.43], p = 0.004) and 6–10 year-olds (5.71-fold [95% CI, 2.38–13.72], p = 0.002) vaccinated with BKSE1.0. Immunogenicity response to BKSE0.5 was low and not significant (1.55-fold [95% CI, 1.24–1.94], p = 0.75). In the ancillary analysis, cumulative incidence of first malaria episodes with ≥5000 parasites/µL was 7 cases/33 subjects in BKSE1.0 and 10 cases/33 subjects in BKSE0.5 vs. 29 cases/66 subjects in the control group. Risk ratio for BKSE1.0 was 0.48 (95% CI, 0.24–0.98; p = 0.04). Conclusion BK-SE36 is safe and immunogenic. The promising potential of BK-SE36, observed in the follow-up study, warrants a double-blind phase 1/2b trial in children under 5 years. Trial Registration Controlled-Trials.com ISRCTN71619711 ISRCTN71619711
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Affiliation(s)
- Nirianne Marie Q. Palacpac
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- The Research Foundation for Microbial Diseases of Osaka University, Suita, Osaka, Japan
| | | | - Adoke Yeka
- Med Biotech Laboratories, Kampala, Uganda
- Makerere University School of Public Health, Kampala, Uganda
| | | | - Nahoko Suzuki
- The Research Foundation for Microbial Diseases of Osaka University, Kanonji, Kagawa, Japan
| | - Hiroki Shirai
- The Research Foundation for Microbial Diseases of Osaka University, Kanonji, Kagawa, Japan
| | - Masanori Yagi
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Kazuya Ito
- Department of Public Health, Faculty of Medicine, Osaka City University, Osaka, Japan
- Sumida Hospital, Medical Co. Living Together Association (LTA) Clinical Pharmacology Center, Tokyo, Japan
| | - Wakaba Fukushima
- Department of Public Health, Faculty of Medicine, Osaka City University, Osaka, Japan
| | - Yoshio Hirota
- Department of Public Health, Faculty of Medicine, Osaka City University, Osaka, Japan
| | | | - Takuya Okada
- The Research Foundation for Microbial Diseases of Osaka University, Kanonji, Kagawa, Japan
| | | | - Kohhei Tetsutani
- The Research Foundation for Microbial Diseases of Osaka University, Suita, Osaka, Japan
- Laboratory of Adjuvant Innovation, National Institute of Biomedical Innovation, Ibaraki City, Osaka, Japan
| | - Nobuko Arisue
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Sawako Itagaki
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Takahiro Tougan
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Ken J. Ishii
- Laboratory of Adjuvant Innovation, National Institute of Biomedical Innovation, Ibaraki City, Osaka, Japan
- Laboratory of Vaccine Science, Immunology Frontier Research Center, World Premier Institute for Immunology, Osaka University, Suita, Osaka, Japan
| | - Shigeharu Ueda
- The Research Foundation for Microbial Diseases of Osaka University, Suita, Osaka, Japan
| | | | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- * E-mail:
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Liu T, Xu G, Guo B, Fu Y, Qiu Y, Ding Y, Zheng H, Fu X, Wu Y, Xu W. An essential role for C5aR signaling in the optimal induction of a malaria-specific CD4+ T cell response by a whole-killed blood-stage vaccine. THE JOURNAL OF IMMUNOLOGY 2013; 191:178-86. [PMID: 23709683 DOI: 10.4049/jimmunol.1201190] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The protective immunity induced by the whole-killed parasite vaccine against malarial blood-stage infection is dependent on the CD4(+) T cell response. However, the mechanism underlying this robust CD4(+) T cell response elicited by the whole-killed parasite vaccine is still largely unknown. In this study, we observe that immunization with Plasmodium yoelii-parasitized RBC lysate activates complement C5 and generates C5a. However, the protective efficacy against P. yoelii 17XL challenge is considerably reduced, and the malaria-specific CD4(+) T cell activation and memory T cell differentiation are largely suppressed in the C5aR-deficient (C5aR(-/-)) mice. An adoptive transfer assay demonstrates that the reduced protection of C5aR(-/-) mice is closely associated with the severely impaired CD4(+) T cell response. This is further confirmed by the fact that administration of C5aR antagonist significantly reduces the protective efficacy of the immunized B cell-deficient mice. Further study indicates that the defective CD4(+) T cell response in C5aR(-/-) mice is unlikely involved in the expansion of CD4(+)CD25(+)Foxp3(+) T cells, but strongly linked to a defect in dendritic cell (DC) maturation and the ability to allostimulate CD4(+) T cells. These results demonstrate that C5aR signaling is essential for the optimal induction of the malaria-specific CD4(+) T cell response by the whole-killed parasite vaccine through modulation of DCs function, which provides us with new clues to design an effective blood-stage subunit vaccine and helps us to understand the mechanism by which the T cell response is regulated by the complement system.
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Affiliation(s)
- Taiping Liu
- Department of Pathogenic Biology, Third Military Medical University, Chongqing 400038, People's Republic of China
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Chen E, Paing MM, Salinas N, Sim BKL, Tolia NH. Structural and functional basis for inhibition of erythrocyte invasion by antibodies that target Plasmodium falciparum EBA-175. PLoS Pathog 2013; 9:e1003390. [PMID: 23717209 PMCID: PMC3662668 DOI: 10.1371/journal.ppat.1003390] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 04/15/2013] [Indexed: 02/06/2023] Open
Abstract
Disrupting erythrocyte invasion by Plasmodium falciparum is an attractive approach to combat malaria. P. falciparum EBA-175 (PfEBA-175) engages the host receptor Glycophorin A (GpA) during invasion and is a leading vaccine candidate. Antibodies that recognize PfEBA-175 can prevent parasite growth, although not all antibodies are inhibitory. Here, using x-ray crystallography, small-angle x-ray scattering and functional studies, we report the structural basis and mechanism for inhibition by two PfEBA-175 antibodies. Structures of each antibody in complex with the PfEBA-175 receptor binding domain reveal that the most potent inhibitory antibody, R217, engages critical GpA binding residues and the proposed dimer interface of PfEBA-175. A second weakly inhibitory antibody, R218, binds to an asparagine-rich surface loop. We show that the epitopes identified by structural studies are critical for antibody binding. Together, the structural and mapping studies reveal distinct mechanisms of action, with R217 directly preventing receptor binding while R218 allows for receptor binding. Using a direct receptor binding assay we show R217 directly blocks GpA engagement while R218 does not. Our studies elaborate on the complex interaction between PfEBA-175 and GpA and highlight new approaches to targeting the molecular mechanism of P. falciparum invasion of erythrocytes. The results suggest studies aiming to improve the efficacy of blood-stage vaccines, either by selecting single or combining multiple parasite antigens, should assess the antibody response to defined inhibitory epitopes as well as the response to the whole protein antigen. Finally, this work demonstrates the importance of identifying inhibitory-epitopes and avoiding decoy-epitopes in antibody-based therapies, vaccines and diagnostics. Malaria is a devastating parasitic disease that kills one million people annually. The parasites invade and multiply within red blood cells, leading to the clinical symptoms of malaria. Therefore, preventing red blood cell, entry through vaccines is an attractive approach to controlling the disease. Although widespread efforts to develop a vaccine by identifying and combining critical parasite blood-stage proteins are underway, a protective vaccine for malaria has proved challenging. This is in part because, while parasite proteins have the ability to elicit antibodies that prevent red blood cell invasion, these antibodies are a small proportion compared to the total collection of ineffective antibodies produced. We show an antibody that prevents red blood cell invasion targets regions of the critical parasite protein PfEBA-175 required for red blood cell engagement. We also show that an antibody that does not prevent red blood cell invasion recognizes a region far removed from important functional segments of PfEBA-175. Our work demonstrates that identifying the regions targeted by antibodies, and the mechanisms by which antibodies that prevent invasion function, should drive future vaccine development and studies measuring the effectiveness of current vaccine combinations.
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Affiliation(s)
- Edwin Chen
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - May M. Paing
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Nichole Salinas
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - B. Kim Lee Sim
- Protein Potential, Rockville, Maryland, United States of America
| | - Niraj H. Tolia
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- * E-mail:
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Broad-spectrum antimalarial activity of peptido sulfonyl fluorides, a new class of proteasome inhibitors. Antimicrob Agents Chemother 2013; 57:3576-84. [PMID: 23689711 DOI: 10.1128/aac.00742-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite declining numbers of cases and deaths, malaria remains a major public health problem in many parts of the world. Today, case management relies heavily on a single class of antimalarial compounds: artemisinins. Hence, development of resistance against artemisinins may destroy current malaria control strategies. Beyond malaria control are elimination and eradication programs that will require drugs with good activity against acute infection but also with preventive and transmission-blocking properties. Consequently, new antimalarials are needed not only to ensure malaria control but also for elimination and eradication efforts. In this study, we introduce peptido sulfonyl fluorides (PSF) as a new class of compounds with antiplasmodial activity. We show that PSF target the plasmodial proteasome and act on all asexual stages of the intraerythrocytic cycle and on gametocytes. PSF showed activities at concentrations as low as 20 nM against multidrug-resistant and chloroquine-sensitive Plasmodium falciparum laboratory strains and clinical isolates from Gabon. Structural requirements for activity were identified, and cytotoxicity in human HeLa or HEK 293 cells was low. The lead PSF PW28 suppressed growth of Plasmodium berghei in vivo but showed signs of toxicity in mice. Considering their modular structure and broad spectrum of activity against different stages of the plasmodial life cycle, proteasome inhibitors based on PSF have a great potential for further development as preclinical candidate compounds with improved species-specific activity and less toxicity.
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Kang JM, Ju HL, Moon SU, Cho PY, Bahk YY, Sohn WM, Park YK, Cha SH, Kim TS, Na BK. Limited sequence polymorphisms of four transmission-blocking vaccine candidate antigens in Plasmodium vivax Korean isolates. Malar J 2013; 12:144. [PMID: 23631662 PMCID: PMC3654915 DOI: 10.1186/1475-2875-12-144] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 04/27/2013] [Indexed: 12/02/2022] Open
Abstract
Background Transmission-blocking vaccines (TBVs), which target the sexual stages of malaria parasites to interfere with and/or inhibit the parasite’s development within mosquitoes, have been regarded as promising targets for disrupting the malaria transmission cycle. In this study, genetic diversity of four TBV candidate antigens, Pvs25, Pvs28, Pvs48/45, and PvWARP, among Plasmodium vivax Korean isolates was analysed. Methods A total of 86 P. vivax-infected blood samples collected from patients in Korea were used for analyses. Each of the full-length genes encoding four TBV candidate antigens, Pvs25, Pvs28, Pvs48/45, and PvWARP, were amplified by PCR, cloned into T&A vector, and then sequenced. Polymorphic characteristics of the genes were analysed using the DNASTAR, MEGA4, and DnaSP programs. Results Polymorphism analyses of the 86 Korean P. vivax isolates revealed two distinct haplotypes in Pvs25 and Pvs48/45, and three different haplotypes in PvWARP. In contrast, Pvs28 showed only a single haplotype. Most of the nucleotide substitutions and amino acid changes identified in all four TBV candidate antigens were commonly found in P. vivax isolates from other geographic areas. The overall nucleotide diversities of the TBV candidates were much lower than those of blood stage antigens. Conclusions Limited sequence polymorphisms of TBV candidate antigens were identified in the Korean P. vivax population. These results provide baseline information for developing an effective TBV based on these antigens, and offer great promise for applications of a TBV against P. vivax infection in regions where the parasite is most prevalent.
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Affiliation(s)
- Jung-Mi Kang
- Department of Parasitology and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, 660-751, South Korea
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Portugal S, Pierce SK, Crompton PD. Young lives lost as B cells falter: what we are learning about antibody responses in malaria. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:3039-46. [PMID: 23526829 PMCID: PMC3608210 DOI: 10.4049/jimmunol.1203067] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Plasmodium falciparum malaria remains a major public health threat for which there is no licensed vaccine. Abs play a key role in malaria immunity, but Ab-mediated protection is only acquired after years of repeated infections, leaving children in endemic areas vulnerable to severe malaria and death. Many P. falciparum Ags are extraordinarily diverse and clonally variant, which likely contribute to the inefficient acquisition of protective Abs. However, mounting evidence suggests that there is more to the story and that infection-induced dysregulation of B cell function also plays a role. We herein review progress toward understanding the B cell biology of P. falciparum infection, focusing on what has been learned from population-based studies in malaria-endemic areas. We suggest ways in which advances in immunology and genomics-based technology can further improve our understanding of the B cell response in malaria and perhaps illuminate new pathways to the development of effective vaccines.
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Affiliation(s)
- Silvia Portugal
- Laboratory of Immunogenetics, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
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Yu FD, Yang SY, Li YY, Hu W. Co-expression network with protein–protein interaction and transcription regulation in malaria parasite Plasmodium falciparum. Gene 2013; 518:7-16. [DOI: 10.1016/j.gene.2012.11.092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 11/27/2012] [Indexed: 12/16/2022]
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Zhao J, Deng S, Liang J, Cao Y, Liu J, Du F, Shang H, Cui L, Luo E. Immunogenicity, protective efficacy and safety of a recombinant DNA vaccine encoding truncated Plasmodium yoelii sporozoite asparagine-rich protein 1 (PySAP1). Hum Vaccin Immunother 2013; 9:1104-11. [PMID: 23357857 DOI: 10.4161/hv.23688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Although great efforts have been undertaken for the development of malaria vaccines, no completely effective malaria vaccines are available yet. Despite being clinically silent, the pre-erythrocytic stage is considered an ideal target for the development of malaria vaccines. Sporozoite asparagine-rich protein 1 (SAP1) is a sporozoite-localized protein that regulates the expression of UIS (upregulated in infectious sporozoites) genes, which are essential for the infectivity of sporozoites. In this study, a recombinant DNA vaccine encoding a predicted antigenic determinant region of Plasmodium yoelii SAP1 (PySAP1) was constructed. Immunization of mice with this DNA vaccine construct resulted in significant elevation of cytokines such as IFN-γ, IL-2, IL-4 and IL-10, and total IgG as compared with control groups immunized with either the empty DNA vector or saline. After challenge with sporozoites, the group receiving the DNA vaccine showed delayed development of parasitemia and prolonged survival time compared with the control group. The DNA vaccine provided partial protection against P. yoelii 17XL infection, with an overall protection rate of 20%. In addition, the DNA vaccine did not show integration into the host genome. Further studies of SAP1 are needed to test whether it can be used as subunit vaccine candidate.
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Affiliation(s)
- Jia Zhao
- Department of Pathogen Biology; College of Basic Medical Sciences; China Medical University; Shenyang, Liaoning P.R. China
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137
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Pakpour N, Akman-Anderson L, Vodovotz Y, Luckhart S. The effects of ingested mammalian blood factors on vector arthropod immunity and physiology. Microbes Infect 2013; 15:243-54. [PMID: 23370408 DOI: 10.1016/j.micinf.2013.01.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 12/11/2022]
Abstract
The blood feeding behavior of disease-transmitting arthropods creates a unique intersection between vertebrate and invertebrate physiology. Here, we review host blood-derived factors that persist through blood digestion to affect the lifespan, reproduction, and immune responses of some of the most common arthropod vectors of human disease.
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Affiliation(s)
- Nazzy Pakpour
- Department of Medical Microbiology and Immunology, University of California, Davis, CA 95616, United States.
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138
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Abstract
Pregnant women have a higher risk of malaria compared to non-pregnant women. This review provides an update on knowledge acquired since 2000 on P. falciparum and P.vivax infections in pregnancy. Maternal risk factors for malaria in pregnancy (MiP) include low maternal age, low parity, and low gestational age. The main effects of MIP include maternal anaemia, low birth weight (LBW), preterm delivery and increased infant and maternal mortality. P. falciparum infected erythrocytes sequester in the placenta by expressing surface antigens, mainly variant surface antigen (VAR2CSA), that bind to specific receptors, mainly chondroitin sulphate A. In stable transmission settings, the higher malaria risk in primigravidae can be explained by the non-recognition of these surface antigens by the immune system. Recently, placental sequestration has been described also for P.vivax infections. The mechanism of preterm delivery and intrauterine growth retardation is not completely understood, but fever (preterm delivery), anaemia, and high cytokines levels have been implicated. Clinical suspicion of MiP should be confirmed by parasitological diagnosis. The sensitivity of microscopy, with placenta histology as the gold standard, is 60% and 45% for peripheral and placental falciparum infections in African women, respectively. Compared to microscopy, RDTs have a lower sensitivity though when the quality of microscopy is low RDTs may be more reliable. Insecticide treated nets (ITN) and intermittent preventive treatment in pregnancy (IPTp) are recommended for the prevention of MiP in stable transmission settings. ITNs have been shown to reduce malaria infection and adverse pregnancy outcomes by 28–47%. Although resistance is a concern, SP has been shown to be equivalent to MQ and AQ for IPTp. For the treatment of uncomplicated malaria during the first trimester, quinine plus clindamycin for 7 days is the first line treatment and artesunate plus clindamycin for 7 days is indicated if this treatment fails; in the 2nd and 3rd trimester first line treatment is an artemisinin-based combination therapy (ACT) known to be effective in the region or artesunate and clindamycin for 7 days or quinine and clindamycin. For severe malaria, in the second and third trimester parenteral artesunate is preferred over quinine. In the first trimester, both artesunate and quinine (parenteral) may be considered as options. Nevertheless, treatment should not be delayed and should be started immediately with the most readily available drug.
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139
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Host defenses to protozoa. Clin Immunol 2013. [DOI: 10.1016/b978-0-7234-3691-1.00047-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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140
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Baird JK. Tropical Health and Sustainability. Infect Dis (Lond) 2013. [DOI: 10.1007/978-1-4614-5719-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Ali ZMI, Bakli M, Fontaine A, Bakkali N, Vu Hai V, Audebert S, Boublik Y, Pagès F, Remoué F, Rogier C, Fraisier C, Almeras L. Assessment of Anopheles salivary antigens as individual exposure biomarkers to species-specific malaria vector bites. Malar J 2012; 11:439. [PMID: 23276246 PMCID: PMC3547717 DOI: 10.1186/1475-2875-11-439] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 12/19/2012] [Indexed: 01/08/2023] Open
Abstract
Background Malaria transmission occurs during the blood feeding of infected anopheline mosquitoes concomitant with a saliva injection into the vertebrate host. In sub-Saharan Africa, most malaria transmission is due to Anopheles funestus s.s and to Anopheles gambiae s.l. (mainly Anopheles gambiae s.s. and Anopheles arabiensis). Several studies have demonstrated that the immune response against salivary antigens could be used to evaluate individual exposure to mosquito bites. The aim of this study was to assess the use of secreted salivary proteins as specific biomarkers of exposure to An. gambiae and/or An. funestus bites. Methods For this purpose, salivary gland proteins 6 (SG6) and 5′nucleotidases (5′nuc) from An. gambiae (gSG6 and g-5′nuc) and An. funestus (fSG6 and f-5′nuc) were selected and produced in recombinant form. The specificity of the IgG response against these salivary proteins was tested using an ELISA with sera from individuals living in three Senegalese villages (NDiop, n = 50; Dielmo, n = 38; and Diama, n = 46) that had been exposed to distinct densities and proportions of the Anopheles species. Individuals who had not been exposed to these tropical mosquitoes were used as controls (Marseille, n = 45). Results The IgG responses against SG6 recombinant proteins from these two Anopheles species and against g-5′nucleotidase from An. gambiae, were significantly higher in Senegalese individuals compared with controls who were not exposed to specific Anopheles species. Conversely, an association was observed between the level of An. funestus exposure and the serological immune response levels against the f-5′nucleotidase protein. Conclusion This study revealed an Anopheles salivary antigenic protein that could be considered to be a promising antigenic marker to distinguish malaria vector exposure at the species level. The epidemiological interest of such species-specific antigenic markers is discussed.
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Affiliation(s)
- Zakia M I Ali
- Unité de recherche en biologie et épidémiologie parasitaires, Armed Forces Biomedical Research Institute, antenne Marseille, GSBdD de Marseille Aubagne, 111 avenue de la corse, Marseille cedex 02, France
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Anders KL, Hay SI. Lessons from malaria control to help meet the rising challenge of dengue. THE LANCET. INFECTIOUS DISEASES 2012; 12:977-84. [PMID: 23174383 PMCID: PMC3574272 DOI: 10.1016/s1473-3099(12)70246-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Achievements in malaria control could inform efforts to control the increasing global burden of dengue. Better methods for quantifying dengue endemicity-equivalent to parasite prevalence surveys and endemicity mapping used for malaria-would help target resources, monitor progress, and advocate for investment in dengue prevention. Success in controlling malaria has been attributed to widespread implementation of interventions with proven efficacy. An improved evidence base is needed for large-scale delivery of existing and novel interventions for vector control, alongside continued investment in dengue drug and vaccine development. Control of dengue is unlikely to be achieved without coordinated international financial and technical support for national programmes, which has proven effective in reducing the global burden of malaria.
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Affiliation(s)
- Katherine L Anders
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.
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143
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Identification of a potent combination of key Plasmodium falciparum merozoite antigens that elicit strain-transcending parasite-neutralizing antibodies. Infect Immun 2012. [PMID: 23184525 DOI: 10.1128/iai.01107-12] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Blood-stage malaria vaccines that target single Plasmodium falciparum antigens involved in erythrocyte invasion have not induced optimal protection in field trials. Blood-stage malaria vaccine development has faced two major hurdles, antigenic polymorphisms and molecular redundancy, which have led to an inability to demonstrate potent, strain-transcending, invasion-inhibitory antibodies. Vaccines that target multiple invasion-related parasite proteins may inhibit erythrocyte invasion more efficiently. Our approach is to develop a receptor-blocking blood-stage vaccine against P. falciparum that targets the erythrocyte binding domains of multiple parasite adhesins, blocking their interaction with their receptors and thus inhibiting erythrocyte invasion. However, with numerous invasion ligands, the challenge is to identify combinations that elicit potent strain-transcending invasion inhibition. We evaluated the invasion-inhibitory activities of 20 different triple combinations of antibodies mixed in vitro against a diverse set of six key merozoite ligands, including the novel ligands P. falciparum apical asparagine-rich protein (PfAARP), EBA-175 (PfF2), P. falciparum reticulocyte binding-like homologous protein 1 (PfRH1), PfRH2, PfRH4, and Plasmodium thrombospondin apical merozoite protein (PTRAMP), which are localized in different apical organelles and are translocated to the merozoite surface at different time points during invasion. They bind erythrocytes with different specificities and are thus involved in distinct invasion pathways. The antibody combination of EBA-175 (PfF2), PfRH2, and PfAARP produced the most efficacious strain-transcending inhibition of erythrocyte invasion against diverse P. falciparum clones. This potent antigen combination was selected for coimmunization as a mixture that induced balanced antibody responses against each antigen and inhibited erythrocyte invasion efficiently. We have thus demonstrated a novel two-step screening approach to identify a potent antigen combination that elicits strong strain-transcending invasion inhibition, supporting its development as a receptor-blocking malaria vaccine.
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Fontaine A, Fusaï T, Briolant S, Buffet S, Villard C, Baudelet E, Pophillat M, Granjeaud S, Rogier C, Almeras L. Anopheles salivary gland proteomes from major malaria vectors. BMC Genomics 2012; 13:614. [PMID: 23148599 PMCID: PMC3542285 DOI: 10.1186/1471-2164-13-614] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Accepted: 10/29/2012] [Indexed: 01/29/2023] Open
Abstract
Background Antibody responses against Anopheles salivary proteins can indicate individual exposure to bites of malaria vectors. The extent to which these salivary proteins are species-specific is not entirely resolved. Thus, a better knowledge of the diversity among salivary protein repertoires from various malaria vector species is necessary to select relevant genus-, subgenus- and/or species-specific salivary antigens. Such antigens could be used for quantitative (mosquito density) and qualitative (mosquito species) immunological evaluation of malaria vectors/host contact. In this study, salivary gland protein repertoires (sialomes) from several Anopheles species were compared using in silico analysis and proteomics. The antigenic diversity of salivary gland proteins among different Anopheles species was also examined. Results In silico analysis of secreted salivary gland protein sequences retrieved from an NCBInr database of six Anopheles species belonging to the Cellia subgenus (An. gambiae, An. arabiensis, An. stephensi and An. funestus) and Nyssorhynchus subgenus (An. albimanus and An. darlingi) displayed a higher degree of similarity compared to salivary proteins from closely related Anopheles species. Additionally, computational hierarchical clustering allowed identification of genus-, subgenus- and species-specific salivary proteins. Proteomic and immunoblot analyses performed on salivary gland extracts from four Anopheles species (An. gambiae, An. arabiensis, An. stephensi and An. albimanus) indicated that heterogeneity of the salivary proteome and antigenic proteins was lower among closely related anopheline species and increased with phylogenetic distance. Conclusion This is the first report on the diversity of the salivary protein repertoire among species from the Anopheles genus at the protein level. This work demonstrates that a molecular diversity is exhibited among salivary proteins from closely related species despite their common pharmacological activities. The involvement of these proteins as antigenic candidates for genus-, subgenus- or species-specific immunological evaluation of individual exposure to Anopheles bites is discussed.
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Affiliation(s)
- Albin Fontaine
- Unité de Parasitologie - UMR6236, URMITE - IFR48, Antenne Marseille de l'Institut de Recherche Biomédicale des Armées (IRBA), BP 60109, Marseille Cedex 07, 13 262, France
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145
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Huang J, Li X, Kohno K, Hatano M, Tokuhisa T, Murray PJ, Brocker T, Tsuji M. Generation of tissue-specific H-2Kd transgenic mice for the study of K(d)-restricted malaria epitope-specific CD8+ T-cell responses in vivo. J Immunol Methods 2012; 387:254-61. [PMID: 23142461 DOI: 10.1016/j.jim.2012.10.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/24/2012] [Accepted: 10/31/2012] [Indexed: 11/17/2022]
Abstract
CD8(+) T cells are critical for the control of various intracellular infections and cancers. To date, however, effective T cell-based vaccines remain elusive, due, in part, to the lack of in vivo models that facilitate the dissection of antigen-specific CD8(+) T-cell responses primed by different antigen-presenting cells (APCs). In this study, we generated four lines of H-2K(d) transgenic (K(d) Tg) mice that differed in their expression of H-2K(d): dendritic cells (DCs) only (CD11c-K(d)), macrophages only (huCD68-K(d)), hepatocytes only (Alb-K(d)), or all nucleated cells (major histocompatibility complex-I-K(d)). Immunization of each of these K(d) Tg mouse strains with a synthetic peptide or a recombinant adenovirus expressing a well-known immunodominant, H-2K(d)-restricted CD8(+) T-cell epitope, SYVPSAEQI, which was derived from the circumsporozoite protein of Plasmodium yoelii, promoted distinct SYVPSAEQI-specific CD8(+) T-cell responses. The route of immunization also greatly influenced the magnitude of the epitope-specific CD8(+) T-cell response. These tissue-specific K(d) Tg mice may be valuable tools for determining the mode of induction of CD8(+) T-cell responses by different APCs in vivo and for characterizing the CD8(+) T-cell responses promoted in response to various microbial infections and/or different types of vaccines.
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Affiliation(s)
- Jing Huang
- HIV and Malaria Vaccine Program, Aaron Diamond AIDS Research Center, Affiliate of the Rockefeller University, New York, NY 10016, USA
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146
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Williams AR, Douglas AD, Miura K, Illingworth JJ, Choudhary P, Murungi LM, Furze JM, Diouf A, Miotto O, Crosnier C, Wright GJ, Kwiatkowski DP, Fairhurst RM, Long CA, Draper SJ. Enhancing blockade of Plasmodium falciparum erythrocyte invasion: assessing combinations of antibodies against PfRH5 and other merozoite antigens. PLoS Pathog 2012; 8:e1002991. [PMID: 23144611 PMCID: PMC3493472 DOI: 10.1371/journal.ppat.1002991] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/11/2012] [Indexed: 02/01/2023] Open
Abstract
No vaccine has yet proven effective against the blood-stages of Plasmodium falciparum, which cause the symptoms and severe manifestations of malaria. We recently found that PfRH5, a P. falciparum-specific protein expressed in merozoites, is efficiently targeted by broadly-neutralizing, vaccine-induced antibodies. Here we show that antibodies against PfRH5 efficiently inhibit the in vitro growth of short-term-adapted parasite isolates from Cambodia, and that the EC50 values of antigen-specific antibodies against PfRH5 are lower than those against PfAMA1. Since antibody responses elicited by multiple antigens are speculated to improve the efficacy of blood-stage vaccines, we conducted detailed assessments of parasite growth inhibition by antibodies against PfRH5 in combination with antibodies against seven other merozoite antigens. We found that antibodies against PfRH5 act synergistically with antibodies against certain other merozoite antigens, most notably with antibodies against other erythrocyte-binding antigens such as PfRH4, to inhibit the growth of a homologous P. falciparum clone. A combination of antibodies against PfRH4 and basigin, the erythrocyte receptor for PfRH5, also potently inhibited parasite growth. This methodology provides the first quantitative evidence that polyclonal vaccine-induced antibodies can act synergistically against P. falciparum antigens and should help to guide the rational development of future multi-antigen vaccines. Malaria is the most devastating parasitic disease of humans, resulting in an estimated 0.6–1 million deaths per year. The symptoms of malaria are caused when merozoites invade and replicate within red blood cells, and therefore a vaccine which induced antibodies that effectively prevent this invasion process would be a major step towards the control of the disease. However, development of such a vaccine has proved extremely challenging. A major roadblock has been the probable need for extremely high levels of antibodies to achieve vaccine efficacy. We have now shown that antibodies against the merozoite protein PfRH5 are able to neutralize the invasion of red blood cells by malaria parasites at concentrations that are significantly lower than for antibodies against PfAMA1 – the previous leading blood-stage malaria vaccine target. This neutralization was observed in both laboratory-adapted parasite lines and in five different parasite isolates from Cambodian patients with malaria. Furthermore, we found that by combining antibodies against PfRH5 with antibodies against certain other merozoite antigens we could achieve synergistic neutralization of parasites, further lowering the amount of antibody needed to be induced by a vaccine. The development of vaccines encoding the PfRH5 antigen in combination with a second target may thus be the best way to achieve the long-sought after goal of an efficacious blood-stage malaria vaccine. Moreover, the methodology described here to assess the ability of antibodies against different targets to synergize should greatly aid the future rational design of improved vaccine candidates.
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147
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Bagai U, Pawar A. A blood stage fraction of Plasmodium berghei induces protective and long lasting immune response in BALB/c mice. Parasitol Int 2012; 62:329-36. [PMID: 23085043 DOI: 10.1016/j.parint.2012.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 10/09/2012] [Accepted: 10/10/2012] [Indexed: 11/25/2022]
Abstract
Incorporation of the parasite's subcellular fractions in subunit vaccines can be a possible approach for formulation of vaccine against malaria. In this study, the immunogenicity and protective efficacy of 10,000g fraction of blood stage Plasmodium berghei was evaluated in mouse model. This fraction induced higher levels of anti-parasite antibodies and provided complete and long lasting protection as compared to whole parasite antigens. Antiserum raised against it was immunoadsorbed on CNBr activated sepharose-4B to elute antigens from this fraction. Eluted antigens were characterized electrophoretically, and after lyophilization these were designated as ML-I (having 55, 64, 66, and 74kDa proteins), ML-II (having 51, 64, 66, and 72kDa proteins) and ML-III (having only 47kDa protein) sub-fractions. Mice were immunized with these sub-fractions and immune responses induced by various immunization regimens were evaluated and compared with that of 10,000g fraction. These sub-fractions imparted partial protection except ML-III, which was non-protective. 10,000g fraction as a whole provided complete protection and generated significantly higher level of IL-2 and IFN-γ in immune mice. ML-I produced significant amount of IL-1 and IL-4 as compared to ML-II. Enhanced level of malaria-specific IgG1 was produced by ML-II, but IgG2a was significantly higher in ML-I immunized mice. Conclusively, this study identifies 10,000g fraction as a promising blood stage vaccine candidate and suggests that a vaccine based upon multiple antigens may be more efficacious as compared to single antigen based formulations.
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Affiliation(s)
- Upma Bagai
- Parasitology Laboratory, Department of Zoology, Panjab University, Chandigarh, India.
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148
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Screening and Evaluation of Inhibitors of Plasmodium falciparum Merozoite Egress and Invasion Using Cytometry. Methods Mol Biol 2012. [PMID: 22990802 DOI: 10.1007/978-1-62703-026-7_36] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2024]
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149
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Schlarman MS, Roberts RN, Kariuki MM, LaCrue AN, Ou R, Beerntsen BT. PFE0565w, a Plasmodium falciparum protein expressed in salivary gland sporozoites. Am J Trop Med Hyg 2012; 86:943-54. [PMID: 22665598 DOI: 10.4269/ajtmh.2012.11-0797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Because malaria is still a significant problem worldwide, additional control methods need to be developed. The Plasmodium sporozoite is a good target for control measures because it displays dual infectivity for both mosquito and vertebrate host tissues. The Plasmodium falciparum gene, PFE0565w, was chosen as a candidate for study based on data from PlasmoDB, the Plasmodium database, indicating that it is expressed both at the transcriptional and protein levels in sporozoites, likely encodes a putative surface protein, and may have a potential role in the invasion of host tissues. Additional sequence analysis shows that the PFE0565w protein has orthologs in other Plasmodium species, but none outside of the genus Plasmodium. PFE0565w expresses transcript during both the sporozoite and erythrocytic stages of the parasite life cycle, where an alternative transcript was discovered during the erythrocytic stages. Data show that transcript is not present during axenic exoerythrocytic stages. Despite transcript being present in several life cycle stages, the PFE0565w protein is present only during the salivary gland sporozoite stage. Because the PFE0565w protein is present in salivary gland sporozoites, it could be a novel candidate for a pre-erythrocytic stage vaccine.
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Affiliation(s)
- Maggie S Schlarman
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
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150
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Zeeshan M, Alam MT, Vinayak S, Bora H, Tyagi RK, Alam MS, Choudhary V, Mittra P, Lumb V, Bharti PK, Udhayakumar V, Singh N, Jain V, Singh PP, Sharma YD. Genetic variation in the Plasmodium falciparum circumsporozoite protein in India and its relevance to RTS,S malaria vaccine. PLoS One 2012; 7:e43430. [PMID: 22912873 PMCID: PMC3422267 DOI: 10.1371/journal.pone.0043430] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 07/20/2012] [Indexed: 11/19/2022] Open
Abstract
RTS,S is the most advanced malaria vaccine candidate, currently under phase-III clinical trials in Africa. This Plasmodium falciparum vaccine contains part of the central repeat region and the complete C-terminal T cell epitope region (Th2R and Th3R) of the circumsporozoite protein (CSP). Since naturally occurring polymorphisms at the vaccine candidate loci are critical determinants of the protective efficacy of the vaccines, it is imperative to investigate these polymorphisms in field isolates. In this study we have investigated the genetic diversity at the central repeat, C-terminal T cell epitope (Th2R and Th3R) and N-terminal T cell epitope regions of the CSP, in P. falciparum isolates from Madhya Pradesh state of India. These isolates were collected through a 5-year prospective study aimed to develop a well-characterized field-site for the future evaluation of malaria vaccine in India. Our results revealed that the central repeat (63 haplotypes, n = 161) and C-terminal Th2R/Th3R epitope (24 haplotypes, n = 179) regions were highly polymorphic, whereas N-terminal non-repeat region was less polymorphic (5 haplotypes, n = 161) in this population. We did not find any evidence of the role of positive natural selection in maintaining the genetic diversity at the Th2R/Th3R regions of CSP. Comparative analysis of the Th2R/Th3R sequences from this study to the global isolates (n = 1160) retrieved from the GenBank database revealed two important points. First, the majority of the sequences (∼61%, n = 179) from this study were identical to the Dd2/Indochina type, which is also the predominant Th2R/Th3R haplotype in Asia (∼59%, n = 974). Second, the Th2R/Th3R sequences in Asia, South America and Africa are geographically distinct with little allele sharing between continents. In conclusion, this study provides an insight on the existing polymorphisms in the CSP in a parasite population from India that could potentially influence the efficacy of RTS,S vaccine in this region.
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Affiliation(s)
- Mohammad Zeeshan
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Mohammad Tauqeer Alam
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Sumiti Vinayak
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Hema Bora
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Rupesh Kumar Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Mohd Shoeb Alam
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Vandana Choudhary
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Pooja Mittra
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Vanshika Lumb
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | | | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Neeru Singh
- Regional Medical Research Centre for Tribals, Jabalpur, Madhya Pradesh, India
| | - Vidhan Jain
- Regional Medical Research Centre for Tribals, Jabalpur, Madhya Pradesh, India
| | | | - Yagya Dutta Sharma
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
- * E-mail:
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