Allospecific T-cell lines with functional activities.

A T-lymphocyte line and sublines from it reactive with Class II MHC alloantigens have been examined for proliferative responses and helper activity in vitro and in vivo. Both the parent cell line and its derived sublines recognize alloantigenic determinants encoded for by the I-A subregion of the H-2 complex in a proliferative assay, and have regulatory activity for allogeneic and syngeneic B cells in two different helper systems. The in vitro selected cell populations are approximately twenty-fold more active in functional helper assays than populations selected in vivo by priming. Differential analysis of the patterns of proliferative responses of sublines against allogeneic I-A molecules on different backgrounds indicates that one type of selected cells reacts preferentially to MHC molecules presented on the background used for selection.