Specificity and function of a human autologous reactive T cell

Normal human peripheral blood contains a population of T cells (autologous reactive cells [ARC]) capable of proliferating in response to signals from autologous B cells and monocytes. Selective suicide of proliferating ARC with 5-bromo-2-deoxyuridine and light demonstrated that this ARC was responsive to signals coded for by genes more closely linked to the HLA-DR, than to the HLA-A, or HLA-B, loci. Density-gradient fractionation of T cells indicated that populations enriched in ARC reactivity were also enriched for helper influences required for Ig synthesis by autologous B cells. In contrast, populations negatively selected for proliferating ARC were deficient in helper activity. These studies indicate that the ARC is responsive, at least in part, to products of genes closely linked to the HLA-DR locus and can function as a helper cell.