The H57-597 monoclonal antibody is specific for the beta chain of the mouse T cell Receptor (TCR). The crosslinking induces activation and proliferation of T cells, as a plate-bound or a soluble H57-597, or the plate-bound antibody can induce apoptosis, based on assay conditions. The beta chain of the TCR can combine with the alpha chain of the receptor to produce the alpha-beta TCR, which is expressed by the NKT cells, by the NK1.1+ thymocytes and most of the T cells. The beta chain does not react with the gamma-delta TCR-bearing cells, expressed by a small number of T cells. This antibody can be used as a phenotypic marker for the TCR beta expressing cells or for the functional purpose of TCR-mediated cell activation or apoptosis.