Prevention of Toxic Effects of Injected Thromboplastin by "Thromboplastinase".

Abstract

Loss of potency of tissue thromboplastic suspensions due to "thromboplastinase" action results in a concomitant loss of toxicity. Boiling does not alter the toxicity of thromboplastin. The lipid moiety of thromboplastin appears to be essential for the production of toxic reactions. Prior intraven. injn. of "thromboplastinase" into rabbits protected against subsequent injns. of a min. toxic dose of thromboplastin. Heat-inactivated "thromboplastinase" did not induce this protection. Active "thromboplastinase," in doses up to 10 times that needed for protection, caused no untoward reactions in the animals. The mechanism of the protective effect in vivo seems to be different from the in vitro destruction of thromboplastin by "thromboplastinase.".