[Immunomodulating effect of protein fractions isolated from bifidobacteria]

The screening of the immunomodulating activity (IMA) of different protein fractions isolated from bifidobacteria was carried out and the capacity of these fractions for changing the proliferative activity of immunocompetent cells was evaluated. Soluble proteins were extracted from lyophilized and sonicated bacterial mass of B. bifidum strain 1 in Na2HPO4 (pH 8) in a water bath at 65 degrees C for 30 minutes. After the formation and removal of nucleic acid sediment the resulting supernatant fluid was dialyzed, its adsorption spectra were analyzed and the fluid was fractionated in a specially proposed device for preparative electrophoresis. Protein fractions were tested for IMA on spleen cells of CBA mice in the reaction of lymphocyte blast-transformation by the level of the inclusion 3H thymidine. The analysis of IMA of protein fractions revealed that their high-molecular components produced a pronounced dose-dependent effect on the proliferative activity of spleen cells. The fractions containing low-molecular components were either inactive (fraction 4) or active only in the maximum dose (fraction 5).