NK1.1+ thymocytes. Adult murine CD4-, CD8- thymocytes contain an NK1.1+, CD3+, CD5hi, CD44hi, TCR-V beta 8+ subset.
CD4-, CD8- thymocytes were purified from thymi obtained from normal C57BL/6 mice. By flow cytometry analysis, 5 to 10% of these double negative (DN) thymocytes were found to express NK1.1 on their surface. The NK1.1+ DN thymocytes were demonstrated, by two-color fluorescence, to be CD3lo, CD5hi, CD44hi, J11d-, B220-, MEL 14-, IL2R- with 60% expressing TCR-V beta 8 as determined by the mAb F23.1. In contrast, splenic and peripheral blood NK cells were NK1.1+, CD3-, CD5-, TCR-V beta 8- with 40 to 60% being MEL 14+. Unlike peripheral NK cells, fresh DN thymocytes enriched for NK1.1+ cells were unable to kill YAC-1, the classical murine NK cell target. However, these cells were able to mediate anti-CD3 redirected lysis even when they were assayed immediately after purification, i.e., with no culture or stimulation. These data demonstrate that adult murine thymocytes contain NK1.1+ cells which are distinct, both by function and phenotype, from peripheral NK cells. These data also raise the issue of a possible NK/T bipotential progenitor cell.
Iowa City Veterans Administration, IA.
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D000818:Animals; D015703:Antigens, CD / Q000032:analysis*; D000943:Antigens, Differentiation / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D017252:CD3 Complex; D018956:CD5 Antigens; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000032:analysis*; D016201:Receptors, Lymphocyte Homing; D013601:T-Lymphocytes / Q000276:immunology*
D015703:Antigens, CD; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D018956:CD5 Antigens; D011948:Receptors, Antigen, T-Cell; D016201:Receptors, Lymphocyte Homing