Inhibition of mixed lymphocyte response by monoclonal antibody specific for a rat T lymphocyte subset.

Cell-surface differentiation antigens which are associated with particular lymphocyte subsets are likely to be molecules which mediate specific functions of the cells which display them. One way to investigate this hypothesis is to see whether antibodies directed against such antigens will inhibit functional systems. This approach can be attempted with confidence if monoclonal antibodies are used, as these react with one antigenic determinant only and can be used in purified form. In this report we show that a monoclonal antibody which is specific for a subset of rat tT lymphocytes inhibits the mixed lymphocyte response (MLR). The antibody acts on the responder cells without killing them.