[Immunoglobulins A and G in the intestinal secretions of rats in different microbiologic conditions].

Experiments were made with 3 groups of inbred CDF (F344) Crl rats: 30 germ-free, 30 conventional and 18 germ-free animals infected orally with Shigella flexneri 2aN 516. Secretory IgA (S-IgA) was isolated from gut secretion of the conventional rats to obtain rabbit antiserum against it. The levels of S-IgA, IgA and IgG in blood serum and gut secretion were determined.

[Characteristics of strains of Citrobacter 037 (5396/38) isolated from guinea pigs in a gnotobiologic experiment].

No changes in the principal biochemical properties characteristic of the given genus occurred in a gnotobiological experiment of passing Citrobacter bacteria through microbe free and exmicrobe-free animals. Of 28 strains of this genus isolated in the course of investigation two strains lost their arginine-decarboxylase activity. In the cultures studied the quantitative content of the Vi-antigen had a tendency to reduction in comparison with the initial culture used for the association.