[The immunomodulating properties of the filtrates of Klebsiella culture broth and the nature of the immunomodulating factor].

Influence of broth culture filtrates (BCF) of Klebsiella on delayed type hypersensitivity (DTN) in mice has been studied. BCF of plasmid-containing virulent strains and non-plasmid avirulent strains have been found to suppress DTH to xenogenic splenocytes. Gel filtration data have shown that immunosuppressive factor possesses molecular weight about 180-800 kDa. BCF treated with etanol-ether mixture got to soluble fraction that evidenced for its lipid nature. This factor can be inactivated or reactivated by the treatment with trichloracetic acid, phenol and other chemicals. A new factor is found in reactivated BCF. It induces the ability of E. coli O55 to suppress DTH in mice and looks like Shigella factor. It is supposed that Klebsiella immunosuppressive factors are connected with lipopolysaccharide.