Identification of surface and internal antigens from spontaneously releasedPlasmodium falciparum merozoites by radio-iodination and metabolic labelling

Publisher Website
Google Scholar
Abstract
Spontaneously released merozoites from synchronousPlasmodium falciparum cultures were isolated in the presence of protease blocker. 1–5×1010 merozoites were obtained in each experiment. The isolated merozoites possessed a thick surface coat and about 80% were invasive to human erythrocytes although they did not subsequently develop into ring stages. Tests using several analytical methods showed the merozoite preparations to be free of any erythrocyte contamination. Six labelled proteins were identified after surface radio-iodination, the largest with a molecular weight of 82000. All six proteins were precipitated with various immune sera. Four other proteins with molecular weights of 200000 and 160000–145000 (a triplet) were identified by precipitation with the same immune sera after metabolically labelling the merozoites. The six surface proteins were not prominent in the metabolically labelled preparations. Using these methods it is possible to identify and differentiate between surface and internal merozoite antigens.