Studies on Antigens from Axenically Cultivated Entamoeba Histolytica and Entamoeba Histolytica-Like Amebae

Abstract

Antigens were prepared from four different strains of axenically cultivated E. histolytica and the E. histolytica-like amebae (Laredo strain). Antigen protein yields averaging 8.7 mg were obtained from 107 E. histolytica. Immunoelectrophoresis revealed six to eight distinct bands between 200:NIH antiserum and antigens from strains 200:NIH. HB-301:NIH, F-22, and HK-9 while only two distinct bands were detected between 200:NIH antiserum and the histolytica-like Laredo-strain antigen. In the hemagglutination test an antigen concentration of 30–40 µg protein per ml was adequate for sensitization of erythrocytes. Antigen from the Laredo strain was less reactive in the HA test than were the other antigens. These observations suggest that the histolytica-like Laredo strain is immunologically different from the typical strains of E. histolytica.