A morphological study in germfree mice (Salmonella infection).

The morphological manifestation of the intestinal infections of Salmonella typhimurium by the intestine rolled method in both conventional DKI and germfree mice have been investigated in our laboratory. In the conventional mice, the morphological manifestation of intestinal infection shows no difference from the general features of infection, while in the germfree mice, the manifestation is characterized by the so-called non-reactive necrotizing enteritis without cellular reaction. When infection in the germfree mice occurs, some state of immunological insufficiency should be taken into consideration. In infections of germfree mice it is difficult to consider the immunological or the allergic reaction which is expected in the conventional mice. In addition, the direct influences of bacteria such as endotoxin must be taken into consideration as another possibility, but the very limited localized lesions, as seen in this experiment cannot always be suggested to be due to the direct influence of bacteria or intoxication. Though there are many problems to be solved in the future, we are now able to state a kind of mechanism similar to that of Shwartzman's phenomenon cannot be ignored in the infection in newborns or in immunologically immature animals.