Double-negative (CD4^-CD8^-) lymphocytes bearing T-cell receptor α and β chains in normal human skin

Double-negative (CD4^-CD8^-) T-cell receptor α- and β-chain (TCRαβ)-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 α- and β-chain transcripts and lacked TCR γ- and δ-chain as well as CD4 and CD8 mRNAs. These polyclonal cell lines shared one predominant TCR β-chain gene rearrangement. The CD3/TCRαβ 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^- TCRαβ 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.