[Comparative study of the proliferative activity of human lymphocytes from different pairs of donors in a mixed culture in vitro].

The proliferative response of human lymphocytes was studied in one-way and two-way mixed lymphocyte cultures (MLC). The maximal proliferation was shown to be attained in a two-way MLC containing unequal quantities of the cells from two paired donors. It was also demonstrated in a one-way MLC that the cells of one of the two paired donors are more effective responders. The most powerful proliferation in the MLC of these donors was observed in the cultures containing the excess of more effective cells. Thymosine increased the response of human lymphocytes in the two-way MLC. In vitro cell preincubation reduced the response in the cultures with a high proliferative response in the control. It has been thus demonstrated that lymphocytes from paired donors possess different functional activity in the MLC.