Shwartzman reaction in endotoxin-resistant rabbits induced by heterologous endotoxin.

Moderate resistance to and endotoxin was induced in rabbits. The endotoxin-resistant rabbits did not respond with a Shwartzman reaction if the skin preparation was carried out by endotoxin and the provocation by endotoxin. However, the same animals showed definite haemorrhagic reactions if their skin was prepared by endotoxin from other serological types, e.g. or endotoxin. endotoxin resistant rabbits did not display the Shwartzman reaction if the skin preparation was carried out by endotoxin. On the contrary, they displayed marked Shwartzman reactions at the sites of the skin preparation with endotoxin. The provocation of this haemorrhagic reaction could be carried out either by or by endotoxin. The above results point to the possibility of the role of an immunological specificity in the skin preparation of the Shwartzman phenomenon. No such specificity could be demonstrated with regards to the intravenous provocation of the reaction. The immunospecificity (serological specificity) in the preparation of the Shwartzman reaction is limited, because it disappears if a higher degree of resistance is established. The immunospecificity in resistance or in sensitivity is dose-dependent. By raising the preparing or provoking doses, the Shwartzman reaction can be induced by heterologous or homologous endotoxins in rabbits that have a higher degree of resistance. The possible cause is discussed.