title: Immunogenicity of well-characterized synthetic Plasmodium falciparum multiple antigen peptide conjugates.
abstract: Given the emerging difficulties with malaria drug resistance and vector control, as well as the persistent lack of an effective vaccine, new malaria vaccine development strategies are needed. We used a novel methodology to synthesize and fully characterize multiple antigen peptide (MAP) conjugates containing protective epitopes from Plasmodium falciparum and evaluated their immunogenicity in four different strains of mice. A di-epitope MAP (T3-T1) containing two T-cell epitopes of liver stage antigen-1 (LSA-1), a di-epitope MAP containing T-cell epitopes from LSA-1 and from merozoite surface protein-1, and a tri-epitope MAP (T3-CS-T1) containing T3-T1 and a potent B-cell epitope from the circumsporozoite protein central repeat region were tested in this study. Mice of all four strains produced peptide-specific antibodies; however, the magnitude of the humoral response indicated strong genetic restriction between the different strains of mice. Anti-MAP antibodies recognized stage-specific proteins on the malaria parasites in an immunofluorescence assay. In addition, serum from hybrid BALB/cJ x A/J CAF1 mice that had been immunized with the tri-epitope MAP T3-CS-T1 successfully inhibited the malaria sporozoite invasion of hepatoma cells in vitro. Spleen cells from immunized mice also showed a genetically restricted cellular immune response when stimulated with the immunogen in vitro. This study indicates that well-characterized MAPs combining solid-phase synthesis and conjugation chemistries are potent immunogens and that this approach can be utilized for the development of subunit vaccines.
authors.affiliation: Laboratory of Parasitic Biology and Biochemistry, Office of Vaccine Research and Review, Maryland, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Joshi
authors.forename: A A
authors.initials: AA
authors.lastname: Gam
authors.forename: R A
authors.initials: RA
authors.lastname: Boykins
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: J
authors.initials: J
authors.lastname: Sacci
authors.forename: S L
authors.initials: SL
authors.lastname: Hoffman
authors.forename: H L
authors.initials: HL
authors.lastname: Nakhasi
authors.forename: R T
authors.initials: RT
authors.lastname: Kenney
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis / Q000145:classification; D000918:Antibody Specificity; D000953:Antigens, Protozoan / Q000276:immunology*; D002455:Cell Division; D002478:Cells, Cultured; D005260:Female; D007371:Interferon-gamma / Q000032:analysis; D017780:Malaria Vaccines / Q000276:immunology*; D016778:Malaria, Falciparum / Q000235:genetics* / Q000276:immunology / Q000517:prevention & control; D020066:Merozoite Surface Protein 1 / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000276:immunology; D010963:Plasmodium falciparum / Q000276:immunology; D015800:Protozoan Proteins / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018074:Vaccines, Conjugate / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D017780:Malaria Vaccines; D020066:Merozoite Surface Protein 1; D010455:Peptides; D015800:Protozoan Proteins; D018074:Vaccines, Conjugate; C041595:circumsporozoite protein, Protozoan; C067302:liver stage-specific antigen, Plasmodium; D007371:Interferon-gamma