Identification of a novel antigenic domain of Plasmodium falciparum merozoite surface protein-1 that specifically binds to human erythrocytes and inhibits parasite invasion, in vitro

Merozoite surface protein 1 (MSP-1) of Plasmodium falciparum is a promising candidate for vaccine development against malaria. Identification of prote ctive epitopes within MSP-1 is an important step towards the elucidation of mechanisms of parasitic invasion and for the creation of a multi-subunit v accine. In this study, we show that a 115 amino acid region (p115MSP-1) wit hin the p38 domain of MSP-1 can: (i) specifically bind to human erythrocyte s, independent of glycophorin A; (ii) inhibit parasite invasion at signific ant levels, in vitro; and (iii) be recognized by human sera of individuals from malaria-endemic regions of Africa. More importantly, we also show that polyclonal antibodies specific to this region prevent parasite invasion at levels approaching 90%, in vitro. Our data illustrate that not only is p11 5MSP-1 involved in parasite recognition/invasion of human erythrocytes, but that this region is highly antigenic, producing high titer antibodies. The delineation of the role of MSP-1 in parasite invasion is an important comp onent of the development of a multi-subunit malaria vaccine, and this study identifies a candidate antigen in this context. (C) 2000 Elsevier Science B.V. All rights reserved.