Specificities of antibodies to Plasmodium falciparum merozoite surface protein (MSP)-119

In a survey of children living in South Western Nigeria, plasma levels of anti-MSP1(19) antibodies were not associated with patent parasitemia. Anti-MSP1(19) antibody titres correlated positively with age, indicating that development of antibodies to MSP1(19) may depend on long-term exposure to parasites. Using competitive ELISA, 82% of the samples inhibited the binding of processing-inhibitory monoclonal antibodies (mAb) 12.8 and 12.10 to immobilized recombinant MSP1(19). The binding of mAb 12.8 in the presence of 18% of these samples was reduced to less than 10%. This suggest that these samples contain polyclonal antibodies that have a similar binding specificity to that of mAb 12.8, which recognizes an epitope located in the first epidermal growth factor domain of MSP1(19). Our data provide useful leads for the design of an MSP1(19)-based vaccine.