Inhibition of lymphocyte production via thymic factors.

摘要: A protein fraction capable of inhibiting both in vitro and vivo lymphocyte DNA synthesis was purified, starting from a particle-free crude water extract calf thymus using selective precipitations with ethanol ammonium sulphate. The semipurified T4-P2 showed preferential inhibitory activity rat thymocyte synthesis, to lesser extent bone marrow newborn liver cells. Non-hemopoietic cell types proved be insensitive T4-P2. In addition similar mouse tissue extracts (P2 fractions testes, kidney, liver, lung) had no effect on the spontaneous proliferation indicating specific presence bioactive factor. PHA-induced T-lymphocyte transitorily inhibited at late G1 S phase mitotic cycle. Also, this active decreasing the3H-thymidine incorporation into spleen time dependently after single administration.