[Low-molecular immunomodulators of natural origin].

It was shown that low molecular peptides Nos. 1 and 2 produced by soil bacteria had a pronounced immunostimulating effect. When the preparations were administered at various periods with respect to immunization the number of AFC in the spleen of immunized animals increased 2-4 times. Preparation No. 2 in a dose of 0.5-25 mg/kg increased delayed type hypersensitivity and hemagglutinin levels in blood serum. The maximum effect was observed when the preparation was administered 24 or 48 hours after immunization. The ability to stimulate immunological processes in animals may probably be attributed to the fact that preparations Nos. 1 and 2 are efficient against carcinoma 755 and not toxic in vitro.