The relative transmission of natural and pepsin-refined homologous antitoxin from the uterine cavity to the foetal circulation in the rabbit

Abstract

Natural and pepsin-digested rabbit antitoxins were compared with respect to their transmission to the foetal circulation in rabbits. The experiments were so designed that the foetuses were exposed simultaneously to the two antitoxins in rabbit serum injected into the uterine cavity. The natural antitoxin was transmitted readily, but the pepsin-digested antitoxin was not transmitted at the lowest concentrations tested, so that concentration quotients for pepsin-digested antitoxin ranged from <1/6 to <1/30 of those for natural antitoxin. It is concluded that the pepsinized moiety of an homologous antitoxin molecule is transmitted less readily than the whole.