A NOVEL MEROZOITE SURFACE-ANTIGEN OF PLASMODIUM-FALCIPARUM (MSP-3) IDENTIFIED BY CELLULAR-ANTIBODY COOPERATIVE MECHANISM ANTIGENICITY AND BIOLOGICAL-ACTIVITY OF ANTIBODIES

We report the identification of a 48kDa antigen targeted by antibodies which inhibit Plasmodium falciparum in vitro growth by cooperation wi th blood monocytes in an ADCI assay correlated to the naturally acquir ed protection. This protein is located on the surface of the merozoite stage of P. falciparum, and is detectable in all isolates tested Epid emiological studies demonstrated that peptides derived from the amino acid sequence of MSP-3 contain potent B and T-cell epitopes recognized by a majority of individuals living in endemic areas. Moreover human antibodies either purified on the recombinant protein, or on the synth etic peptide MSP-3b, as well as antibodies raised in mice were all fou nd to promote parasite killing mediated by monocytes.