[Role of ontogenetically different thymocytes in subpopulations of T-cells in releasing a humoral lymphocytic factor]. / Rol' ontogeneticheski razlichnykh timotsitov i subpopuliatsii t-kletok v vysvobozhdenii gumoral'nogo limfotsitarnogo faktora.

ABSTRACT

The activated mouse T-cells release in the culture medium a factor suppressing the ability of stem hemopoietic cells to form hemopoietic colonies in the spleens of lethally irradiated recipients. The factor of stem cell inhibition (FISC) obtained from the mouse thymocytes on the 1st, 7th and 10th day of postnatal life does not differ, by its inhibiting activity, from that obtained from the adult thymocytes, whereas the embryonic thymocytes under similar experimental conditions released FISC with a low inhibiting activity. A study of some physical-chemical and biological properties of FISC has shown that the latter is actively synthesized both by cortical and medullary thymocytes, has no (linear) specificity and resembles, by its characteristics, lymphokins of a wide effect, such as MIF and LT, rather than short-distant mediators, such as suppressor and helper factors.