The Wellcome Trust Lecture: Genes for antigens ofPlasmodium falciparum

Abstract

Sporozoites ofP. falciparumand other Plasmodia appear to be fairly simple antigenically, in that there is a dominant antigen, the circumsporozoite (CS) protein that forms the sporozoite surface coat (Potocnjak, Yoshida, Nussenzweig & Nussensweig, 1980; Santoroet al.1983). Consequently, the CS protein and the gene encoding it have now been studied in considerable detail (Elliset al.1983; Godsonet al.1983; Ozakiet al.1983; Dameet al.1984; Eneaet al.1984). In contrast to sporozoites, the asexual blood stagesof P. falciparumare antigenically complex. Two-dimensional gel analyses of immunoprecipitated, biosynthetically labelled antigens indicate that repeated infection withP. falciparumresults in the synthesis of antibodies against a large number of distinct antigens (Perrin & Dayal, 1982; Brownet al.1981, 1983). In further contrast to the sporozoite, the asexual blood stages of differentP. falciparumisolates exhibit a high degree of antigenic heterogeneity (Brownet al.1983; Hallet al.1983; McBride, Walliker & Morgan, 1982). Much of this antigenic diversity is no doubt due to allelic differences but clonal populations of parasites may also have the capacity to undergo antigenic variation (Hommel, David & Oligino, 1983).