Detection of HLA-DRw (Ia-like) antigens on human T lymphocytes grown in tissue culture.

Human T lymphocytes that proliferate in the presence of conditioned medium from PHA-stimulated allogeneic peripheral blood cells were shown to express IPA antigens after the 8th culture day. Ia antigens as detected by xenogeneic antisera were present on 80 to 90% of the cultured cells which were also strongly reactive with xenogeneic antisera defining a human T cell antigen and formed E rosettes. Control cultures with PHA or no conditioned medium expressed T cell but not Ia antigens. These cultured T cells also express the same HLA-DRw determinants as the B cells of the donor they were derived from. Absorption of xenogeneic Ia, and HLA-DRw alloantisera with cultured T cells completely removed the reactivity of these sera for enriched peripheral blood B lymphocytes from normal donors.