T cell receptor expression by dendritic epidermal T cells.

Abstract

Dendritic epidermal T cells (DETC) in murine epidermis express the gamma delta T cell receptor (TCR). The major population of DETC utilize V gamma 5 and V delta 1 without any junctional diversity, corresponding to the earliest fetal thymocytes which express TCR gamma delta. Using PCR, we recently found another population of DETC which express V gamma 1-V delta 6 with junctional diversity in addition to V gamma 5-V delta 1, although they exist in small numbers in normal mice. In athymic nude mice, V gamma 1+ cells also exist. Therefore, this subset of gamma delta T cells is the product of an extrathymic pathway. These V gamma 1+ cells may recognize mycobacterium antigen or heat shock protein (HSP), thus playing an important role in the first defense of the skin. In contrast to normal mice, in nude mice, we could not detect any DETC using anti CD3 epsilon antibody (2C11). In order to solve this puzzle, we examined the components of TCR complex utilizing immunoprecipitation and northern blot analysis. TCR is composed of either alpha beta or gamma delta chains associated with CD3 gamma, delta, epsilon and zeta-zeta chains. By immunoprecipitation of 125I labelled DETC cell lines using anti-CD3 epsilon antibody, we detected gamma delta chains and CD3 gamma and CD3 epsilon chains, but not CD3 delta or CD3 zeta chains. Northern blot analysis showed that these cells express CD3 gamma, epsilon, and zeta chains, but not the CD3 delta chain.(ABSTRACT TRUNCATED AT 250 WORDS)