PROTHYMOSIN-ALPHA AND FACTORS FROM CALF THYMIC CELLS DECREASE EXPRESSION OF THY-1.2 ANTIGEN AMONG SMALL THYMOCYTES FROM C57BL 6 MICE/

In this work we studied the effect of Prothymosin alpha (ProT alpha) a nd other thymic factors on the expression of Thy 1.2 antigen (a T-cell marker) and the activities of adenosine deaminase (ADA, E.C. 3.5.4.4) , N-acetyl-beta-D-glucosaminidase (NABG, E.C. 3.2.1.30), beta-glucuron idase (BG, E.C. 3.1.1.1) and serine-esterase (SE, E.C. 3.4.21)., the l evels of which change during the T-cell differentiation process among small thymocytes obtained from C57BL/6 mice. Incubation of small thymo cytes in the presence of ProT alpha, Thymus Extracts (TE) or supernata nts prepared from thymic stromal cells (TSCS) or thymocytes (TS) reduc ed the proportion of cells killed by anti-Thy 1.2 monoclonal antibodie s but did not affect the enzymatic activities studied. This is the fir st evidence that ProT alpha affects Thy 1.2 expression in vitro.