[Effect of substances of a polypeptide nature isolated from the thymus, cerebral cortex and substantia alba on the cellular and humoral indices of immunity in thymectomized mice].

Effects of low molecular weight polypeptides (M. W. lower 10,000) isolated from the calf thymus, cortex and white matter of the brain by extraction with acetic acid on the cellular and humoral immune responses were studied in experimental thymectomized mature CBA mice. Thymectomy reduced markedly the number of T-cells in the spleen. Accordingly, the ability to generate both Ig M and IgG antibody forming cells as well as humoral antibodies to thymus-dependent antigen, SRBC, was significantly suppressed in the animals. Subcutaneous administration of 1 micron/g (body weight) of the thymus and brain cortex polypeptides during 8 days not only completely restored T-cells population in the spleen and immune responsibility but also elevated these values 1.5-2 fold in comparison with sham controls which had been given saline solution. The preparation from the white matter of the brain lacked biological activity.