A 46,000 dalton Plasmodium falciparum merozoite surface glycoprotein not related to the 185,000-195,000 dalton schizont precursor molecule: isolation and characterization.

A 46,000 dalton glycoprotein was isolated by extraction of freshly harvested P. falciparum merozoites (FCB1 strain), followed by gel electrophoresis of the extract and electroelution. The antigen is present in the late ring, trophozoite, schizont, and segmenter stages and is localized on the merozoite surface at the end of schizogony. It is not related to the 185,000-195,000 dalton schizont antigen. An antiserum against the 46,000 dalton antigen inhibits invasion of erythrocytes by merozoites. The isolated antigen is identical to the antigen against which monoclonal antibody (mcab) 13.4 is directed.