A human T cell tumor which expresses the putative T cell antigen receptor.

A monoclonal antibody (mAb) called H1-2D4 which reacts only with the T cell line HPB-ALL and not with other T cell lines, normal or activated peripheral blood cells, B lymphoblasts (B-LCL), or thymocytes has been developed. This mAb cocaps the T3 antigen on HPB-ALL and anti-T3 mAb cocaps the antigen which reacts with H1-2D4. Purified H1-2D4 precipitates a heterodimer from HPB-ALL cells which has components with molecular weights of 51 000 and 39 000. The properties of the molecule recognized by H1-2D4 suggest that it is the HPB-ALL equivalent of the putative human T cell antigen receptor.