Ontogeny of human suppressor inducer T cell subset.

A T cell subset (T4+,2H4+) has recently been identified, which acts as an inducer of T8+ suppressor cells; however 2H4 molecules have not been detected in thymuses from normal individuals or on the surface of immature thymocyte clones. In the present study, T4+,2H4+ and T8+,2H4+ cells have been found in maternal and new-born blood samples. However, only a small percentage of 2H4+ cells were detected in human fetal thymus, bone marrow, liver and spleen, thus suggesting that T cells acquire these molecules only in circulation and at a late stage of maturation.