The Interaction between Carrageenan and the First Component of Complement

Carrageenan inhibits the hemolytic activity of C′1a by interfering with the capacity of C′1 (and of C′1a) to become bound to sensitized erythrocytes. Carrageenan has no effect on the esterase activity of C′1a. The degree of inhibition of C′ activity in vivo is too small to be of value in studies on the biologic action of C′.