Abstract
Plasmodium falciparum proteins associated with plasma membranes of infected erythrocytes were identified by using three techniques: isolated plasma membranes from infected and uninfected erythrocytes were compared by gel electrophoresis and silver staining; isolated plasma membranes from cells metabolically labeled with [35S]methionine were assayed by gel electrophoresis; and uninfected and infected intact erythrocytes were surface-labeled by lactoperoxidase iodination, and the labeled polypeptides were compared by gel electrophoresis. The results from these experiments indicate that at least six parasite-derived polypeptides (Mr = greater than 240,000, 150,000, 55,000, 45,000, 35,000, and 20,000) are associated with the infected erythrocyte plasma membrane. At least four of these peptides (Mr = 55,000, 45,000, 35,000, and 20,000) may be exposed on the surface of the infected erythrocytes.