Ubiquity of the repetitive epitope of the CS protein in different isolates of human malaria parasites.

Sporozoites of the human malaria Plasmodium falciparum and Plasmodium vivax obtained from a large number of endemic areas were screened with species-specific monoclonal antibodies that recognize the repeated epitopes of the respective circumsporozoite (CS) proteins. By using a two-site immunoradiometric assay, it was determined that all the parasite isolates of a given species react with a single monoclonal antibody, indicating the presence of a common repeated epitope. Polyacrylamide gel electrophoresis, followed by Western blot, showed that the CS proteins of the various isolates differed in their apparent m.w.