A subset of natural killer cells in peripheral blood displays a mature T cell phenotype.
Normal human PBMC were analyzed for the presence of cells expressing both T3 and NKH1 antigens, using direct two-color immunofluorescence. In six individuals, NKH1+T3+ cells were found to represent 2.5% of PBMC and 24% of the total number of NKH1+ cells. Purified NKH1+T3+ cells were shown to have the typical morphology of large granular lymphocytes (LGL). NKH1+T3+ cells also exhibited spontaneous cytotoxicity against K562 target cells and this lytic activity could be inhibited by anti-T3 mAb. Similar results were obtained with NKH1+T3+ cells cultured in vitro in lymphocyte-conditioned medium. Taken together, these results indicate that NKH1+T3+ cells represent a unique population of NK-active cells in normal peripheral blood. Although these cells exhibit LGL morphology and NK activity, this appears to be mediated through a functional T cell-like receptor for target antigen.
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis*; D002454:Cell Differentiation; D002469:Cell Separation; D003602:Cytotoxicity, Immunologic; D005455:Fluorescent Antibody Technique; D006801:Humans; D007694:Killer Cells, Natural / Q000145:classification* / Q000276:immunology; D010641:Phenotype; D013601:T-Lymphocytes / Q000145:classification* / Q000166:cytology / Q000276:immunology
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface