THE CANONICAL T-CELL RECEPTOR OF DENDRITIC EPIDERMAL GAMMA-DELTA T-CELLS IS HIGHLY CONSERVED BETWEEN RATS AND MICE

Two monoclonal antibodies with specificity for rat gamma delta T cell receptor (TCR) were generated. One, called V65, reacts with all CD3(+) alpha beta TCR(-) rat T cells and thus recognizes a constant determin ant of the rat gamma delta TCR (Kuhnlein et al., Journal of Immunology 1993, 153:979). The other, called V45, reacts with approximately 80% of gamma delta T cells in peripheral lymphoid organs. In mt epidermis, V65 but not V45 detects a dense network of the dendritic epidermal T cells (DETC). Analysis of epidermal RNA by polymerase chain reaction ( PCR) indicated that V gamma 3 and V delta 1 are the predominant, if no t exclusive TCR V transcripts present at this site. Sequence analysis of cDNA crones obtained by reverse transcription-PCR with V gamma 3- a nd V delta 1-specific primers revealed that the variable domains of ra t DETC gamma and delta chains are very homologous to those described i n mice (92% and 95% identity at the protein level). The complete conse rvation between the two species of the amino acid sequences at the V-( D)-J transitions of this monomorphic receptor indicates that the inter action of the DETC TCR with its as yet unknown ligand must be of centr al importance for DETC function.