The 536 monoclonal antibody specifically recognizes Vγ 3† T-cell Receptor (TCR)-bearing T lymphocytes, which are the predominant γδ TCR-bearing cells in the early fetal thymus and the adult epidermis of euthymic mice. The first T cells to mature in the embryonic thymus express the Vγ 3 and Vδ 1 TCR chains, and their development is dependent upon IL-7. There is evidence that the Vγ 3 TCR-bearing fetal thymocytes are the precursors of the majority of dendritic epidermal T cells (DEC), which may be replenished in the adult by proliferation in situ rather than by seeding from primary lymphoid organs. Although the Vγ 3 TCR is almost exclusively found in the DEC population, it has been shown that the homing of DEC to the epidermis does not require expression of the Vγ 3 gene segment. Vγ 3 TCR-bearing dermal dendritic cells have also been described. Vγ 3 TCR has also been found on a subset of T lymphocytes in the lactating mammary gland and at the site of antigenic challenge in contact-sensitized mice. Plate-bound 536 antibody activates Vγ 3 TCR-bearing T cells, and Fab fragments of mAb 536 block in vitro stimulation of DEC by keratinocytes.
† Please note that the Vγ 3 designation correlates with the nomenclature of Garman, Doherty, and Raulet; the Vγ 5 designation of Heilig and Tonegawa is equivalent.
