Description: The B1.1 monoclonal antibody reacts with the human gamma delta TCR complex. The gamma delta TCR is expressed by a small subset of T cells in the thymus, peripheral lymphoid tissues, intestinal epithelium, and epidermis. The exact specificity, ligand and function of gamma delta TCR-bearing T cells are not yet fully understood; it is suggested that these cells recognize bacterial ligands and some tumor cells in the context of MHC class I-like gene products and play a role in regulation of the immune response and during bacterial infection. This monoclonal can be used as a phenotypic marker for gamma delta TCR-expressing T cells.