Antibody responses stimulated in rabbits, guinea-pigs and mice by recombinant and synthetic portions of a 75 kDa malarial merozoite protein.
The 75 kDa heat-shock-related protein (p75) of Plasmodium falciparum is an abundant, highly conserved, merozoite surface protein. A bacterial clone, C7, produces a polypeptide (C7Ag) of approximately 30 kDa representing the C-terminal 40% of p75. In several species of animals, the C7Ag stimulated high titre IgG antibodies which cross-react with p75. Two major portions of the C7Ag, theoretically predicted to have strong secondary structural preferences, were modelled with four synthetic peptides. An alpha-helical, hydrophilic region, modelled with a 28-mer, proved a poor immunogen in guinea-pigs and several strains of inbred mice, even though it had been a strong immunogen in rabbits. A disulphide-bonded region of the C7Ag was modelled with three peptides of increasing length, namely 49-, 64- and 76-amino acid residues. In general, the order of immunogenicity was 49 less than 64 less than 76-mer. Antibodies to the 76-mer and the 64-mer reacted strongly with the native parasite protein. The data also suggested that the 76-mer was a good model for the region of the molecule it was made to represent.
Sharma
P
P
International Centre for Genetic Engineering and Biotechnology, NII Campus, Shaheed Jeet Singh Marg, New Delhi, India.
Richman
S J
SJ
Reese
R T
RT
D000818:Animals; D000913:Antibodies, Protozoan / Q000032:analysis*; D000954:Antigens, Surface / Q000276:immunology; D006168:Guinea Pigs; D007114:Immunization; D051379:Mice; D008815:Mice, Inbred Strains; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D011817:Rabbits; D011994:Recombinant Proteins / Q000276:immunology; D013045:Species Specificity
D000913:Antibodies, Protozoan; D000954:Antigens, Surface; D015800:Protozoan Proteins; D011994:Recombinant Proteins