[The role of cultured thymic epithelium and dialyzable leukocyte extracts on the maturation process of T cell. Study of their effects on cyclic nucleotides levels in thymocytes].

For thr purpose of clarifing the role of cultured thymic epithelium (CTE) and dialyzable leukocyte extracts (DLE) in the maturation process of T cells, the effects of the thymic epithelial supernatant (TES) and DLE on cyclic nucleotides in thymocytes were studied. TES increased cAMP levels significantly in thymocytes of mice. The activity of TES to increase cAMP levels correlated well with the state of the growth of thymic epithelium. Moreover, TES increased cAMP levels in human thymocytes, and augumented lymphocyte transformation (LT) to mitogens in immunodeficiency diseases. From these effects, it was suggested that TES had the activities such as thymic hormones. CTE of which TES increased cAMP levels in thymocytes of mice were transplanted in patients with Wiskott-Aldrich syndrome and Ataxia-telangiectasia. After the transplantation, augumentation of LT was observed in both patients. From these results, it was speculated that CTE were engrafted and became to exert its effect in the host. We concluded that it was possible to select the CTE appropriately for transplantation by means of examining the activity of TES. The basal levels of human thymocytes were very low compared with those of peripheral blood lymphocytes (PBL). A significant increase of cAMP levels was observed in thymocytes with stimulation of DLE. DLE produced no significant change of cyclic nucleotide levels in PBL. These results suggested that DLE affected the maturation of human thymocytes with involvement of cAMP. Though DLE was proved to contain histamin and prostaglandin E2, it was revealed from the present study that the active component responsible to increase cAMP levels in human thymocytes was different from these substances. Fractions III and IV of DLE obtained with gel filtration showed the activity to increase cAMP. It was suggested that these fractions contained the active component.