A cDNA clone expressing a rhoptry protein of Plasmodium falciparum.

Antibodies from immune humans were used to select a cDNA clone expressing an asexual blood stage antigen of Plasmodium falciparum. The expressed fused polypeptide was used as an affinity reagent to purify human antibodies specific for the corresponding parasite antigen. Western blotting and immunoelectronmicroscopy demonstrated that the antigen was a 105 kDa protein located in the rhoptries of merozoites. The cDNA encodes the carboxy terminus of the rhoptry antigen, a sequence rich both in charged and hydroxy amino acids.