Further studies on the antigenic diversity of the circumsporozoite proteins of the Plasmodium cynomolgi complex.

The circumsporozoite (CS) proteins of strains of the Plasmodium cynomolgi complex have been examined using antisporozoite monoclonal antibodies (Mab) in various immunologic assays. We found extensive antigenic diversity in the repeating immunodominant epitope of the CS proteins of the various strains. Based on the antigenicity and the electrophoretic mobility of their CS protein, the 11 strains that we examined can be placed in 7 distinct groups. Our data also indicate homology between the immunodominant repetitive epitopes of the CS proteins of the Berok strain of P. cynomolgi and the human malaria parasite P. vivax.