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Sheikh IH, Kaushal DC, Chandra D, Kaushal NA. Immunogenicity of a plasmid DNA vaccine encoding 42kDa fragment of Plasmodium vivax merozoite surface protein-1. Acta Trop 2016; 162:66-74. [PMID: 27311385 DOI: 10.1016/j.actatropica.2016.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 06/07/2016] [Accepted: 06/10/2016] [Indexed: 11/17/2022]
Abstract
Plasmodium vivax is the second major human malaria parasite that inflicts debilitating morbidity and consequent economic impact in South-East Asian countries. The relapsing nature of P. vivax along with the emergence of drug-resistant P. vivax strains has emphasized the urgent need for a vaccine. However, the development of an effective vivax vaccine is seriously hampered due to the diversity and variation in parasite antigens and non-availability of suitable animal models. DNA based vaccines represent an alternative approach in inducing immunity to multiple targets from different stages of malaria parasite. DNA prime-boosting strategies induce both antibody mediated and cell-mediated immune responses that are the major mechanisms of protection against malaria parasites. We have earlier studied the immunogenicity and protective efficacy of the soluble and refolded forms of recombinant 42kDa fragment of Plasmodium vivax merozoite surface protein-1 (PvMSP-142) using P. cynomolgi rhesus monkey model. In the present study, we have constructed a recombinant DNA vaccine encoding 42kDa fragment of P. vivax MSP-1 and studied the immunogenicity of PvMSP-142 DNA vaccine construct in mice. The 42kDa gene fragment of PvMSP-1 was PCR amplified using gene specific primers and subcloned into pcDNA 3.1 (+) eukaryotic expression vector. In vitro expression of PvMSP-142 plasmid construct was checked by transfection in COS-1 cell line. Indirect immunofluorescence of transfected COS-1 cells probed with monoclonal antibodies against PvMSP-142 exhibited positive fluorescence. Immunization of BALB/c mice with PvMSP-142-pcDNA vaccine construct revealed the immunogenicity of recombinant vaccine plasmid that can be enhanced by prime boosting with recombinant protein corresponding to the DNA vaccine as evidenced by significant elevation of antibody and the cytokines responses.
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Affiliation(s)
- Inayat Hussain Sheikh
- Division of Parasitology, CSIR- Central Drug Research Institute, Lucknow 226031, India; Department of Biochemistry, Lucknow University, Lucknow, India.
| | - Deep C Kaushal
- Amity University Uttar Pradesh, Lucknow Campus, Lucknow 226028, India.
| | - Deepak Chandra
- Department of Biochemistry, Lucknow University, Lucknow, India.
| | - Nuzhat A Kaushal
- Division of Parasitology, CSIR- Central Drug Research Institute, Lucknow 226031, India.
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Luo J, Yang J, Cheng Y, Li W, Yin TL, Xu WM, Zou YJ. Immunogenicity study of plasmid DNA encoding mouse cysteine-rich secretory protein-1 (mCRISP1) as a contraceptive vaccine. Am J Reprod Immunol 2012; 68:47-55. [PMID: 22429321 DOI: 10.1111/j.1600-0897.2012.01117.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 02/03/2012] [Indexed: 11/28/2022] Open
Abstract
PROBLEM To examine the immunocontraceptive properties of the plasmid pcDNA-mCRISP1 and compare them to the corresponding recombinant mCRISP1 (r-mCRISP1). METHOD OF STUDY RT-PCR and indirect immunofluorescence were performed to observe the mCRISP1 protein expression in COS-7 cells. Three groups of mice received three injections of r-mCRISP1, pcDNA-mCRISP1 or pcDNA vector, respectively. ELISA and Western blot were used to examine the immune responses and immunoreactivity of antisera. Sperm-egg penetration assay was performed to examine the effect of anti-mCRISP1 antibodies in vitro fertilization of mouse oocytes. Fertility and mean litter size were analysed by natural mating. Histological analysis was carried out to look for potential immunopathologic effects of the antibodies. RESULTS COS-7 cells transfected with pcDNA-mCRISP1 present the expression of mCRISP1. Both r-mCRISP1 and pcDNA-mCRISP1 raised an immune response against r-mCRISP1 protein and native CRISP1 in mouse sperm. The titres of anti-mCRISP1 antibodies from DNA immunized mice were significantly lower than that of r-mCRISP1 immunized mice, but it lasted relatively longer. Male and female pcDNA-mCRISP1 injected animals presented a statistically significant reduction in their fertility with no signs of immunopathologic effects. CONCLUSION These studies demonstrated the feasibility of generating an immune response to mCRISP1 protein by DNA vaccine and pcDNA-mCRISP1 plasmid causing significant anti-fertility potential.
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Affiliation(s)
- Jin Luo
- Reproductive Medical Center, Renmin Hospital of Wuhan University, Wuhan, China
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Zhang ZH, Jiang PH, Li NJ, Shi M, Huang W. Oral vaccination of mice against rodent malaria with recombinant Lactococcus lactis expressing MSP-1(19). World J Gastroenterol 2006; 11:6975-80. [PMID: 16437602 PMCID: PMC4717040 DOI: 10.3748/wjg.v11.i44.6975] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM To construct the recombinant Lactococcus lactis as oral delivery vaccination against malaria. METHODS The C-terminal 19-ku fragments of MSP1 (MSP-1(19)) of Plasmodium yoelii 265-BY was expressed in L. lactis and the recombinant L. lactis was administered orally to BALB/c and C57BL/6 mice. After seven interval vaccinations within 4 wk, the mice were challenged with P. yoelii 265-BY parasites of erythrocytic stage. The protective efficacy of recombinant L. lactis was evaluated. RESULTS The peak parasitemias in average for the experiment groups of BALB/c and C57BL/6 mice were 0.8+/-0.4% and 20.8+/-26.5%, respectively, and those of their control groups were 12.0+/-0.8% and 60.8+/-9.6%, respectively. None of the BALB/c mice in both experimental group and control group died during the experiment. However, all the C57BL/6 mice in the control group died within 23 d and all the vaccinated mice survived well. CONCLUSION The results imply the potential of recombinant L. lactis as oral delivery vaccination against malaria.
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Affiliation(s)
- Zhi-Hong Zhang
- Department of Biochemistry, Fudan University, 220 Han Dan Road, Shanghai 200433, China
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Black CG, Barnwell JW, Huber CS, Galinski MR, Coppel RL. The Plasmodium vivax homologues of merozoite surface proteins 4 and 5 from Plasmodium falciparum are expressed at different locations in the merozoite. Mol Biochem Parasitol 2002; 120:215-24. [PMID: 11897127 DOI: 10.1016/s0166-6851(01)00458-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Merozoite surface proteins of Plasmodium falciparum are one major group of antigens currently being investigated and tested as malaria vaccine candidates. Two recently described P. falciparum merozoite surface antigens, MSP4 and MSP5, are GPI-anchored proteins that each contain a single EGF-like domain and appear to have arisen by an ancient gene duplication event. The genes are found in tandem on chromosome 2 of P. falciparum and the syntenic region of the genome was identified in the rodent malarias P. chabaudi, P. yoelii and P. berghei. In these species, there is only a single gene, designated MSP4/5 encoding a single EGF-like domain similar to the EGF-like domain in both PfMSP4 and PfMSP5. Immunization of mice with PyMSP4/5 provides mice with high levels of protection against lethal challenge with blood stage P. yoelii. In this study, we show that in P. vivax, which is quite phylogenetically distant from P. falciparum, both MSP4 and MSP5 homologues can be found with their relative arrangements with respect to the surrounding genes mostly preserved. However, the gene for MSP2, found between MSP5 and adenylosuccinate lyase (ASL) in P. falciparum, is absent from P. vivax. The PvMSP4 and PvMSP5 genes have a two-exon structure and encode proteins with potential signal and GPI anchor sequences and a single EGF-like domain near the carboxyl-terminus. Rabbit antisera raised against purified recombinant proteins show that each of the antisera react with distinct proteins of 62 kDa for PvMSP4 and 86 kDa for PvMSP5 in parasite lysates. Indirect immunofluorescence assays (IFA) localized PvMSP4 over the entire surface of P. vivax merozoites, as expected, whereas, the MSP5 homologue was found to be associated with an apical organellar location consistent with micronemes or over the polar prominence.
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Affiliation(s)
- Casilda G Black
- Department of Microbiology, Monash University, PO Box 53, Calyton 3800 Victoria, Australia
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Kedzierski L, Black CG, Coppel RL. Immunization with recombinant Plasmodium yoelii merozoite surface protein 4/5 protects mice against lethal challenge. Infect Immun 2000; 68:6034-7. [PMID: 10992516 PMCID: PMC101568 DOI: 10.1128/iai.68.10.6034-6037.2000] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5), expressed as a recombinant protein, was highly effective at protecting mice against lethal challenge with P. yoelii. There was a significant correlation between prechallenge antibody levels and peak parasitemia, suggesting that the homologues of PyMSP4/5 in Plasmodium falciparum are promising components of a subunit vaccine against malaria.
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Affiliation(s)
- L Kedzierski
- Department of Microbiology, Monash University 3800, Victoria, Australia
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Wang L, Black CG, Marshall VM, Coppel RL. Structural and antigenic properties of merozoite surface protein 4 of Plasmodium falciparum. Infect Immun 1999; 67:2193-200. [PMID: 10225874 PMCID: PMC115957 DOI: 10.1128/iai.67.5.2193-2200.1999] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Merozoite surface protein 4 (MSP4) of Plasmodium falciparum is a glycosylphosphatidylinositol-anchored integral membrane protein of 272 residues that possesses a single epidermal growth factor (EGF)-like domain near the carboxyl terminus. We have expressed both full-length MSP4 and a number of fragments in Escherichia coli and have used these recombinant proteins to raise experimental antisera. All recombinant proteins elicited specific antibodies that reacted with parasite-derived MSP4 by immunoblotting. Antibody reactivity was highly dependent on the protein conformation. For example, reduction and alkylation of MSP4 almost completely abolished the reactivity of several antibody preparations, including specificities directed to regions of the protein that do not contain cysteine residues and are far removed from the cysteine-containing EGF-like domain. This indicated the presence of conformation-dependent epitopes in MSP4 and demonstrated that proper folding of the EGF-like domain influenced the antigenicity of the entire molecule. The recombinant proteins were used to map epitopes recognized by individuals living in areas where malaria is endemic, and at least four distinct regions are naturally antigenic during infection. Binding of human antibodies to the EGF-like domain was essentially abrogated after reduction of the recombinant protein, indicating the recognition of conformational epitopes by the human immune responses. This observation led us to examine the importance of conformation dependence in responses to other integral membrane proteins of asexual stages. We analyzed the natural immune responses to a subset of these antigens and demonstrated that there is diminished reactivity to several antigens after reduction. These studies demonstrate the importance of reduction-sensitive structures in the maintenance of the antigenicity of several asexual-stage antigens and in particular the importance of the EGF-like domain in the antigenicity of MSP4.
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Affiliation(s)
- L Wang
- Department of Microbiology, Monash University, Clayton, Victoria, 3168, Australia
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Black CG, Wang L, Hibbs AR, Werner E, Coppel RL. Identification of the Plasmodium chabaudi homologue of merozoite surface proteins 4 and 5 of Plasmodium falciparum. Infect Immun 1999; 67:2075-81. [PMID: 10225857 PMCID: PMC115940 DOI: 10.1128/iai.67.5.2075-2081.1999] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies of Plasmodium falciparum have identified a region of chromosome 2 in which are clustered three genes for glycosylphosphatidylinositol (GPI)-anchored merozoite surface proteins, MSP2, MSP5, and MSP4, arranged in tandem. MSP4 and MSP5 both encode proteins 272 residues long that contain hydrophobic signal sequences, GPI attachment signals, and a single epidermal growth factor (EGF)-like domain at their carboxyl termini. Nevertheless, the remainder of their protein coding regions are quite dissimilar. The locations and similar structural features of these genes suggest that they have arisen from a gene duplication event. Here we describe the identification of the syntenic region of the genome in the murine malaria parasite, Plasmodium chabaudi adami DS. Only one open reading frame is present in this region, and it encodes a protein with structural features reminiscent of both MSP4 and MSP5, including a single EGF-like domain. Accordingly, the gene has been designated PcMSP4/5. The homologue of the P. falciparum MSP2 gene could not be found in P. chabaudi; however, the amino terminus of the PcMSP4/5 protein shows similarity to that of MSP2. The PcMSP4/5 gene encodes a protein with an apparent molecular mass of 36 kDa, and this protein is detected in mature stages of the parasite. The protein partitions in the detergent-enriched phase after Triton X-114 fractionation and is localized to the surfaces of trophozoites and developing and free merozoites. The PcMSP4/5 gene is transcribed in both ring and trophozoite stages but appears to be spliced in a stage-specific manner such that the central intron is spliced from the mRNA in the parasitic stage in which the protein is expressed.
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Affiliation(s)
- C G Black
- Department of Microbiology, Monash University, Clayton 3168, Victoria, Australia
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Kang Y, Calvo PA, Daly TM, Long CA. Comparison of Humoral Immune Responses Elicited by DNA and Protein Vaccines Based on Merozoite Surface Protein-1 from Plasmodium yoelii, a Rodent Malaria Parasite. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.8.4211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Immunization with DNA vaccines encoding relevant Ags can induce not only cell-mediated immune response but also humoral immune responses against pathogenic microorganisms in several animal models. Our previous results demonstrated that, when the C terminus (PyC2) of Plasmodium yoelii merozoite surface protein-1 (MSP-1), a leading vaccine candidate against erythrocytic stages of malaria, was expressed as a fusion protein (GST-PyC2) with glutathione S-transferase (GST), it elicited Ab-mediated protective immune responses in BALB/c mice. In our present study, we wished to examine the humoral responses to a DNA vaccine (V3) encoding GST-PyC2. The GST-PyC2 expressed in V3-transfected Cos 7 cells was recognized by a protective monoclonal Ab to PyC2 (mAb302), although the secreted product had undergone N-linked glycosylation. When BALB/c mice were immunized with V3 plasmid, anti-PyC2 Abs were successfully induced. These Abs immunoprecipitated native PyMSP-1 protein and competed with mAb302 for binding to its epitope at a level similar to those elicited by GST-PyC2 protein immunization. However, these Abs had significantly lower titers and avidities, and different isotype profiles and protective capacities against a lethal erythrocytic stage challenge, than those resulting from immunization with GST-PyC2 protein. Most surprising was the finding that, in contrast to protein immunization, there was no significant increase in the avidity of either GST-specific or PyC2-specific IgG Abs during the course of DNA immunization. This suggests that there may be little or no affinity maturation of specific Abs during DNA immunization in this system.
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Affiliation(s)
- Yang Kang
- Department of Microbiology and Immunology, Allegheny University of the Health Sciences, Philadelphia, PA 19129
| | - Paul A. Calvo
- Department of Microbiology and Immunology, Allegheny University of the Health Sciences, Philadelphia, PA 19129
| | - Thomas M. Daly
- Department of Microbiology and Immunology, Allegheny University of the Health Sciences, Philadelphia, PA 19129
| | - Carole A. Long
- Department of Microbiology and Immunology, Allegheny University of the Health Sciences, Philadelphia, PA 19129
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Spencer Valero LM, Ogun SA, Fleck SL, Ling IT, Scott-Finnigan TJ, Blackman MJ, Holder AA. Passive immunization with antibodies against three distinct epitopes on Plasmodium yoelii merozoite surface protein 1 suppresses parasitemia. Infect Immun 1998; 66:3925-30. [PMID: 9673281 PMCID: PMC108453 DOI: 10.1128/iai.66.8.3925-3930.1998] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We have produced monoclonal antibodies against Plasmodium yoelii merozoite surface protein 1 (MSP-1) and have assessed their ability to suppress blood stage parasitemia by passive immunization. Six immunoglobulin G antibodies were characterized in detail: three (B6, D3, and F5) were effective in suppressing a lethal blood stage challenge infection, two (B10 and G3) were partially effective, and one (B4) was ineffective. MSP-1 is the precursor to a complex of polypeptides on the merozoite surface; all of the antibodies bound to this precursor and to an approximately 42-kDa fragment (MSP-142) that is derived from the C terminus of MSP-1. MSP-142 is further cleaved to an N-terminal approximately 33-kDa polypeptide (MSP-133) and a C-terminal approximately 19-kDa polypeptide (MSP-119) comprised of two epidermal growth factor (EGF)-like modules. D3 reacted with MSP-142 but not with either of the constituents MSP-133 and MSP-119, B4 recognized an epitope within the N terminus of MSP-133, and B6, B10, F5, and G3 bound to MSP-119. B10 and G3 bound to epitopes that required both C-terminal EGF-like modules for their formation, whereas B6 and F5 bound to epitopes in the first EGF-like module. These results indicate that at least three distinct epitopes on P. yoelii MSP-1 are recognized by antibodies that suppress parasitemia in vivo.
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Affiliation(s)
- L M Spencer Valero
- Division of Parasitology, National Institute for Medical Research, London NW7 1AA, United Kingdom
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Identification of a Region of PfEMP1 That Mediates Adherence of Plasmodium falciparum Infected Erythrocytes to CD36: Conserved Function With Variant Sequence. Blood 1997. [DOI: 10.1182/blood.v90.9.3766] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractAdherence of mature parasitized erythrocytes (PE) of Plasmodium falciparum to microvascular endothelial cells contributes directly to the virulence and pathology of this human malaria. The malarial variant antigen, P falciparum erythrocyte membrane protein 1 (PfEMP1), has been implicated as the PE receptor for CD36 on endothelial cells. We identified the region of PfEMP1 that mediates adherence of PE to CD36 and showed that a recombinant protein fragment from this region blocked and reversed adherence of antigenically different parasites. Sequence variation was evident in the CD36 binding domain of different PfEMP1 genes, yet many highly conserved residues, particularly cysteine residues, are evident. This suggests a highly conserved shape that mediates adherence to CD36. Immunization with the CD36-binding domain elicited sera that are cross-reactive with the different recombinant proteins but are strain-specific for the PE surface. Novel anti-adherence therapeutics and a malaria vaccine may derived from exploitation of the structure of the CD36 binding domain of PfEMP1.
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Holm I, Nato F, Mendis KN, Longacre S. Characterization of C-terminal merozoite surface protein-1 baculovirus recombinant proteins from Plasmodium vivax and Plasmodium cynomolgi as recognized by the natural anti-parasite immune response. Mol Biochem Parasitol 1997; 89:313-9. [PMID: 9364976 DOI: 10.1016/s0166-6851(97)00128-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- I Holm
- Unité de Parasitologie Expérimentale, CNRS URA 1960, Institut Pasteur, Paris, France
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Rénia L, Ling IT, Marussig M, Miltgen F, Holder AA, Mazier D. Immunization with a recombinant C-terminal fragment of Plasmodium yoelii merozoite surface protein 1 protects mice against homologous but not heterologous P. yoelii sporozoite challenge. Infect Immun 1997; 65:4419-23. [PMID: 9353014 PMCID: PMC175635 DOI: 10.1128/iai.65.11.4419-4423.1997] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
It has been reported previously that immunization with recombinant protein containing the two epidermal growth factor (EGF)-like modules from merozoite surface protein 1 (MSP-1) of Plasmodium yoelii (strain YM) protects mice against a lethal blood-stage challenge with the same parasite strain. Since MSP-1 is expressed in both liver- and blood-stage schizonts and on the surface of merozoites, we evaluated the effectiveness of immunization with recombinant proteins containing either the individual or the two combined EGF-like modules in producing a protective response against a sporozoite challenge. The recombinant protein expressing the combined EGF-like modules of the YM strain protected mice against a homologous sporozoite challenge, and sterile protection, as defined by the absence of detectable blood-stage parasites, was observed in the majority of the mice. In contrast, mice immunized with recombinant P. yoelii YM MSP-1 were not protected against a heterologous challenge with sporozoites from strain 265 BY of P. yoelii. The lack of protection may be explained by differences identified in the amino acid sequences of MSP-1 for the two strains. A recombinant protein containing the two EGF-like modules of MSP-1 from P. yoelii 265 BY was produced and used to immunize mice. These mice were protected against a homologous challenge with sporozoites of P. yoelii 265 BY. The results suggest that a recombinant MSP-1 has potential as a vaccine against malaria, but its efficacy may be limited by sequence polymorphism and selection of variants.
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Affiliation(s)
- L Rénia
- U313 INSERM, CHU Pitié-Salpêtrière, Paris, France.
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De Souza JB, Ling IT, Ogun SA, Holder AA, Playfair JH. Cytokines and antibody subclass associated with protective immunity against blood-stage malaria in mice vaccinated with the C terminus of merozoite surface protein 1 plus a novel adjuvant. Infect Immun 1996; 64:3532-6. [PMID: 8751895 PMCID: PMC174259 DOI: 10.1128/iai.64.9.3532-3536.1996] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A blood-stage malaria antigen comprising the C terminus of merozoite surface protein 1 fused to glutathione S-transferase, combined with an adjuvant formulation containing squalane, Tween 80, and pluronic L121 (AF), administered subcutaneously protected mice against death from a lethal Plasmodium yoelii infection. The protection induced by this antigen-adjuvant combination was compared with that induced by the antigen plus saponin in terms of survival from the lethal infection and clearance of parasitemia. The levels of gamma interferon and interleukin-4 in spleens were measured as indicators of Th1 and Th2 cell activation, and antibody classes and subclasses were determined by immunofluorescence. With a 10-micrograms dose of antigen and AF as adjuvant, all mice recovered, but with saponin as the adjuvant, there were only a few survivors. With 30 micrograms of antigen plus AF, the peak parasitemias were 10-fold lower than those with 10 micrograms; with saponin, survival was slightly improved. The levels of both gamma interferon and interleukin-4 rose more rapidly and to higher levels with AF as the adjuvant than with saponin, and the same was true for immunoglobulin G1 (IgG1), IgG2a, and IgG2b subclasses. Thus, in terms of both cytokine production and antibody levels, AF is a more potent adjuvant for a malaria vaccine than is saponin.
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Affiliation(s)
- J B De Souza
- Department of Immunology, University College London Medical School, United Kingdom
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