Enzymes of Clostridium tertium: effects on blood group and virus receptor substances.

The enzymatic degradation of purified blood group substances represents an increasingly fruitful approach to the elucidation of their immunochemical specificity, and progress to date has recently been reviewed (Kabat, 1956). A number of enzymes from different microorganisms have been described which split one or more of the blood group substances with resultant changes in serological specificity. Stack and Morgan (1949) have investigated enzymes, first studied by Schiff (1935), of Clostridium welchii, which decompose the A, B and O(H) substances. Watkins (1953) described enzymes in cell free extracts of the protozoan Trichomonas foetus which inactivated the A, B, O(H), and Lewis blood group substances; and Watkins and Morgan (1954) have shown that partially purified enzyme preparations from the same source destroyed the O(H), M and N substances on intact erythrocytes without affecting the A, B, P or S antigens. Besides inactivating the specific antigens mentioned, the enzymes of T. foetus rendered all erythrocytes nonspecifically agglutinable (panagglutinable), rendered D-positive cells agglutinable by incomplete anti-D, and inactivated the receptor sites for the hemagglutinin of influenza virus type A (PR8). Cell free extracts of Lactobacillus bifidus (var. penn) have been shown by Gy6rgy, et al. (1952) to possess enzymatic activity against human and animal blood group A, B, and 0(H) substances, being most active against the latter. Iseki and Tsunoda (1952) have reported that cell free extracts of Bacillu-s fulminans, an aerobic spore bearer, show enzymatic