HUMAN-ANTIBODY RESPONSE TO PLASMODIUM-FALCIPARUM MEROZOITE SURFACE PROTEIN-2 IS SEROGROUP SPECIFIC AND PREDOMINANTLY OF THE IMMUNOGLOBULIN G3 SUBCLASS

MSP2 is a merozoite surface protein of Plasmodium falciparum and, as s uch, is a potential component of a malaria vaccine. In this study, we have used a panel of recombinant MSP2 antigens in enzyme-linked immuno sorbent assays to investigate the recognition of MSP2 by antibodies fr om malaria-immune human serum. These recombinant antigens include full -length proteins of serogroups A and B and fragments representing the conserved, group-specific, or repeat regions of each serogroup. Ninety -five percent of the serum samples tested contained MSP2-specific anti bodies: 81% of serum samples tested responded to serogroup A, and 86% responded to serogroup B. The antibody response is directed almost exc lusively towards dimorphic and polymorphic regions of MSP2; the conser ved regions are rarely recognized, and antibodies to serogroups A and B do not cross-react, Interestingly, the antibody response is predomin ately of the cytophilic and complement-fixing subclass immunoglobulin G3.