Analysis of human prenatal and postnatal thymocytes with the anti-Tac monoclonal antibody and recombinant interleukin-2.

The expression of the interleukin-2 (Il-2) receptor on the cell surface membrane of human prenatal and postnatal thymocytes has been studied by flow cytometry. The in vitro responsiveness of these thymocytes to human recombinant Il-2 (rIl-2) was also studied. Prenatal and postnatal thymocytes contained very few Tac positive cells. The different T cell antigens T6, T3, T4, T8, T9, T10, 3A1 and T11 were expressed by the first trimester of fetal development. Recombinant Il-2 alone was able to induce proliferation of human prenatal and postnatal thymocytes. From this study and data in the literature we conclude that hither-to a thymic precursor cell carrying the interleukin-2 receptor as is the case for the murine thymus has not been found in man.