title: Immunogenicity of the repetitive and nonrepetitive peptide regions of the divergent CS protein of Plasmodium knowlesi.
abstract: The circumsporozoite (CS) protein of the Nuri strain of the simian malarial parasite Plasmodium knowlesi was expressed as a fusion protein in E. coli. This fusion protein cross-reacted with the polyclonal monkey sera raised against irradiated sporozoites of another strain (H strain) of P. knowlesi. The antibody against the repeat units of the H strain CS protein was affinity purified from the polyclonal sera by using synthetic repeat peptides. The affinity-purified antibody did not cross-react with the Nuri CS fusion protein. The immunogenicity of different regions of the CS protein was additionally studied by using several synthetic peptides. All but the most COOH-terminal peptide showed cross-reactivity with the polyclonal sera. Because the repeat regions of the CS protein of the two strains are diverse, whereas the non-repetitive regions are immunogenic and conserved, the latter may be better suited for a potential vaccine.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D003001:Cloning, Molecular; D003429:Cross Reactions; D000882:Haplorhini; D010455:Peptides / Q000276:immunology* / Q000302:isolation & purification; D010961:Plasmodium / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D010455:Peptides; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan