Characterization of T cell receptors on resident murine dendritic epidermal T cells

Cell lines derived from Thy-1+ dendritic epidermal cells (Thy-1+DEC) display a marked heterogeneity in T cell receptor (TcR) expression including CD3-associated alpha/beta, C gamma 1/delta or C gamma 2/delta and C gamma 4/delta TcR. In order to investigate whether this heterogeneity is primarily imposed by in vitro culture conditions or, alternatively, is already present within the epidermis, we studied TcR expression by Thy-1+DEC in situ and on freshly isolated epidermal cell suspensions greatly enriched for Thy-1+DEC. Immunolabeling experiments showed that resident Thy-1+DEC are CD45+, Thy-1+, CD3+, TcR V beta 8-, CD5-, CD4- CD8-, CD25- lymphocytes. Immunoprecipitation of lysates from 125I-surface-labeled Thy-1+DEC-enriched epidermal cells with anti-CD3 epsilon, anti-C gamma 1,2,3 and anti-C gamma 4 antibodies, respectively, and subsequent analysis of the precipitates by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed only CD3-associated 35 kDa/45 kDa gamma/delta heterodimers. The demonstration of TcR heterodimers on resident Thy-1+DEC strongly implies that these cells are functional T cells. The selective expression of C gamma 1/delta (C57BL/6) and C gamma 1/delta or C gamma 2/delta (C3H/He) TcR makes these cells useful for the study of gamma/delta TcR function.