Double-negative (CD4-CD8-) lymphocytes bearing T-cell receptor alpha and beta chains in normal human skin

Double-negative (CD4-CD8-) T-cell receptor alpha- and beta-chain (TCR alpha beta)-expressing lymphocytes have been identified in human skin. Two skin-derived lymphocyte cell lines (II-1 and II-2) expressing this phenotype were obtained. They each expressed full-length TCR alpha- and beta-chain transcripts and lacked TCR gamma- and delta-chain as well as CD4 and CD8 mRNAs. These polyclonal cell lines shared one predominant TCR beta-chain gene rearrangement. The CD3/TCR alpha beta complexes were functionally competent as evidenced by their capacity to transduce activation signals resulting in cell proliferation, lymphokine secretion, and cytolytic activity. The demonstration of CD4-CD8-TCR alpha beta lymphocytes as a subpopulation of the skin-associated immune system should contribute to understanding the biologic potential of this cell population as well as of this organ-specific immune system.