Response of Mice to Certain Avirulent Bacteria after Exposure to Sublethal Total Body X-Irradiation.

Abstract
In these experiments, death was associated with bacteremia. When avirulent live bacteria were injected, the recovered organisms were either of the strain inoculated, or were apparently autogenous bacteria. However, when heat-killed bacteria were introduced, the recovered organisms were of autogenousorigin only. It is known that bacteremia, identified with normal bowel inhabitants, is often an integral part of the syndrome observed in animals dying from whole body irradiation. In this instance, however, bacteremia and death were induced in animals exposed to sublethal doses of irradiation and subsequently inoculated with live avirulent, or even dead organisms generically different from the bacteria normally present in the intestines of these animals. This observation may be of importance under conditions where irradiation is a factor and vaccination is indicated.