Synthetic peptides based on conserved Plasmodium falciparum antigens are immunogenic and protective against Plasmodium yoelii malaria

Chauhan, Virander S.; Chatterjee, Shyama; Johar, Paramjeet K.

doi:10.1111/j.1365-3024.1993.tb00606.x

Cited by 15 publications

(10 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observation that carrier-free nonapeptide and 18-mer did not induce antibodies in rabbits or mice lends support to results of previous studies indicating poor immunogenicity of synthetic peptides (2,7,8,21). In sera collected from clinical cases of P. falciparum malaria, we obtained much lower levels of antibodies reactive against the nonapeptide or the 18-mer (unpublished observations), although all of these sera harbored high levels of malaria antibodies as measured in an ELISA with the whole parasite lysate as well as two other synthetic antigens representing B-cell determinants of MSP-1 of P. falciparum (21).…”

Section: Discussionsupporting

confidence: 86%

Antibodies to a conserved-motif peptide sequence of the Plasmodium falciparum thrombospondin-related anonymous protein and circumsporozoite protein recognize a 78-kilodalton protein in the asexual blood stages of the parasite and inhibit merozoite invasion in vitro

et al. 1996

View full text Add to dashboard Cite

Athrombospondin-related anonymous protein (TRAP) of the human malaria parasite Plasmodium falciparum shares highly conserved amino acid sequence motifs with the circumsporozoite protein of all plasmodia sequenced so far, as well as with unrelated proteins like thrombospondin and properdin. Although it was first described as an asexual blood stages protein, there has been some controversy about its expression in these stages. Pursuant to our interest in the conserved sequences within the malaria antigens, we synthesized an 18-residue peptide (18-mer) representing a conserved motif of TRAP and raised polyclonal antibodies against it. In an immunoblot assay in which we probed proteins from the asexual blood stages of the parasite, we found that this antibody recognized predominantly a 78-kDa protein in the whole parasite lysate. Furthermore, in another immunoblot, the recombinant TRAP constructs containing the conserved-motif sequence were distinctly recognized by the antipeptide antibodies, whereas a construct lacking the motif sequence was not, suggesting that the antibodies specifically cross-reacted with a protein which might be a TRAP-like protein present in the asexual blood stages of the parasite. Also, in an immunofluorescence assay, this antibody brightly stained the acetone-fixed trophozoites of the parasite. Most significantly, anti-18-mer immunoglobulin G, as well as antipeptide antibody against a smaller (nonamer) construct representing the most conserved motif within the 18-mer, inhibited the merozoite invasion of erythrocytes in a dose-dependent manner. These results provide evidence of the expression of TRAP or a TRAP-like protein in the asexual blood stages of the parasite and of a possible role of the conserved motifs in the parasite-host cell interaction during the process of invasion.

show abstract

Section: Discussionsupporting

confidence: 86%

Antibodies to a conserved-motif peptide sequence of the Plasmodium falciparum thrombospondin-related anonymous protein and circumsporozoite protein recognize a 78-kilodalton protein in the asexual blood stages of the parasite and inhibit merozoite invasion in vitro

et al. 1996

View full text Add to dashboard Cite

show abstract

“…Similarly, a highly conserved region II motif present in the circumsporozoite protein of all Plasmodium species sequenced so far seems to play an essential role in the sporozoite invasion of hepatocytes (11,30). In fact, we (12), as well as others (36), have shown that immunization with synthetic peptides modeling highly conserved regions of the P. falciparum antigens can even protect mice against live challenge with the murine malaria parasites, viz., P. berghei or P. yoelii. Such conserved portions of malarial proteins are currently the subject of active investigation as putative vaccine molecules.…”

mentioning

confidence: 57%

Characterization of Protective Epitopes in a Highly ConservedPlasmodium falciparumAntigenic Protein Containing Repeats of Acidic and Basic Residues

et al. 1998

View full text Add to dashboard Cite

The delineation of putatively protective and immunogenic epitopes in vaccine candidate proteins constitutes a major research effort towards the development of an effective malaria vaccine. By virtue of its role in the formation of the immune clusters of merozoites, its location on the surface of merozoites, and its highly conserved nature both at the nucleotide sequence level and the amino acid sequence level, the antigen which contains repeats of acidic and basic residues (ABRA) of the human malaria parasitePlasmodium falciparum represents such an antigen. Based upon the predicted amino acid sequence of ABRA, we synthesized eight peptides, with six of these (AB-1 to AB-6) ranging from 12 to 18 residues covering the most hydrophilic regions of the protein, and two more peptides (AB-7 and AB-8) representing its repetitive sequences. We found that all eight constructs bound an appreciable amount of antibody in sera from a large proportion of P. falciparummalaria patients; two of these peptides (AB-1 and AB-3) also elicited a strong proliferation response in peripheral blood mononuclear cells from all 11 human subjects recovering from malaria. When used as carrier-free immunogens, six peptides induced a strong, boostable, immunoglobulin G-type antibody response in rabbits, indicating the presence of both B-cell determinants and T-helper-cell epitopes in these six constructs. These antibodies specifically cross-reacted with the parasite protein(s) in an immunoblot and in an immunofluorescence assay. In another immunoblot, rabbit antipeptide sera also recognized recombinant fragments of ABRA expressed in bacteria. More significantly, rabbit antibodies against two constructs (AB-1 and AB-5) inhibited the merozoite reinvasion of human erythrocytes in vitro up to ∼90%. These results favor further studies so as to determine possible inclusion of these two constructs in a multicomponent subunit vaccine against asexual blood stages of P. falciparum.

show abstract

“…The procedures employed for synthesis, purification, and characterization of the synthetic constructs used in this study were essentially the same as those described in our earlier work (3,7,8,9,22,23,35). Briefly, peptides were synthesized by a stepwise solid-phase procedure (Boc-chemistry) using an automated peptide synthesizer (model 430A; Applied Biosystems, Foster City, Calif.).…”

Section: Methodsmentioning

confidence: 99%

“…We have been interested in defining B-and T-cell epitopes of major malaria vaccine target antigens for their inclusion in subunit vaccine constructs (3,7,8,9,22,23,35). In the present study, we have attempted to characterize T H -cell epitopes in the nonrepeat portion of PfLSA-1 in mice and in humans.…”

mentioning

confidence: 99%

Analysis of Immune Responses against T- and B-Cell Epitopes fromPlasmodium falciparumLiver-Stage Antigen 1 in Rodent Malaria Models and Malaria-Exposed Human Subjects in India

et al. 2000

Self Cite

View full text Add to dashboard Cite

Liver-stage antigen 1 (LSA-1) is a potential vaccine candidate against preerythrocytic stages of malaria. We report here the immunogenicity of linear synthetic constructs delineated as T H -cell determinants from the nonrepeat regions of Plasmodium falciparum LSA-1 in murine models and human subjects from areas where malaria is endemic in Rajasthan State, India. Seven peptide constructs (LS1.1 to LS1.7) corresponding to predicted T-cell sites from both the N-and C-terminal regions and peptide LS1R from a repeat region of PfLSA-1 were synthesized to analyze the cellular immune responses. These linear peptides were also tested for humoral responses in order to determine if there were any overlapping B-cell epitopes in the predicted T-cell sites. Most peptides induced cellular responses in peptide-immunized BALB/c and C57BL/6 mice as measured by proliferation and cytokine analysis. Cross-reactive T-cell recognition of P. falciparum-based peptides in Plasmodium berghei-immune animals was evaluated, but only one peptide, LS1.2 (amino acids 1742 to 1760) triggered T-cell proliferation and interleukin-2 and gamma interferon secretion in P. berghei-immune splenocytes of BALB/c and C57BL/6 mice as well as in Thamnomys gazellae (natural host of P. berghei ANKA). In an enzyme-linked immunosorbent assay with the peptides, only one peptide, LS1.1, was recognized by anti-P. berghei liver-stage serum. Three peptides (LS1.1, LS1.2, and LS1.3) of the eight peptides tested in this study were recognized by a relatively large percentage of P. falciparum-exposed human subjects; the reactivities ranged from ϳ45% for LS1.3 to ϳ60% for LS1.1 and LS1.2. Interestingly, all of the eight putative T-cell determinants were also recognized by the sera collected from malaria patients, although the response was variable in nature. These T H -and B-cell epitopes may be of potential value for preerythrocytic antigen-based malaria subunit vaccine formulations.

show abstract

Synthetic peptides based on conserved Plasmodium falciparum antigens are immunogenic and protective against Plasmodium yoelii malaria

Cited by 15 publications

References 18 publications

Antibodies to a conserved-motif peptide sequence of the Plasmodium falciparum thrombospondin-related anonymous protein and circumsporozoite protein recognize a 78-kilodalton protein in the asexual blood stages of the parasite and inhibit merozoite invasion in vitro

Antibodies to a conserved-motif peptide sequence of the Plasmodium falciparum thrombospondin-related anonymous protein and circumsporozoite protein recognize a 78-kilodalton protein in the asexual blood stages of the parasite and inhibit merozoite invasion in vitro

Characterization of Protective Epitopes in a Highly ConservedPlasmodium falciparumAntigenic Protein Containing Repeats of Acidic and Basic Residues

Analysis of Immune Responses against T- and B-Cell Epitopes fromPlasmodium falciparumLiver-Stage Antigen 1 in Rodent Malaria Models and Malaria-Exposed Human Subjects in India

Contact Info

Product

Resources

About