Human thymus cells. Excellent responders but poor stimulators in 'One Way' mixed lymphocyte reaction.

Human allogeneic 'one-way' mixed lymphocyte reactions between thymus cells and thymus cells were entirely absent. Of twenty-one mixed lymphocyte reactions between peripheral blood lymphocytes as responding cells and thymus cells as stimulating cells, only eleven had a weak but significant reaction. In contrast, a highly significant response was observed in each of eighteen mixed lymphocyte reactions between thymus cells as responding cells and peripheral blood lymphocytes as stimulating cells and in each of eleven mixed lymphocyte reactions between peripheral blood lymphocytes and peripheral blood lymphocytes. These findings indicate that the thymus cells (T lymphocytes) possess excellent proliferative capacity, with little or no stimulating capacity, while peripheral blood lymphocytes (T and B lymphocytes), on the other hand, are good responders, as well as good stimulators, in the mixed lymphocyte reaction.