title: Cultured Lyt-2- L3T4- T lymphocytes from normal thymus or lpr mice express a broad spectrum of cytolytic activity.
abstract: T lymphocytes expressing the surface phenotype Lyt-2- L3T4- represent a minor population of immature thymocytes that appear to be the precursors of mature T cells. Cells with the same apparent surface phenotype also accumulate in vast numbers in the lymphoid tissues of the autoimmune lpr mouse. Lyt-2- L3T4- T lymphocytes from lpr lymph node (LN) or normal thymus express low to undetectable levels, respectively, of surface antigen receptor. In addition, they produce reduced amounts of lymphokines compared with normal T cells and lack precursors of alloantigen-specific cytolytic T lymphocytes. We previously showed that after culture with phorbol esters and interleukin 2, lpr Lyt-2- L3T4- T lymphocytes proliferate and differentiate, acquiring increased levels of surface antigen receptor by most cells, as well as Lyt-2 by a portion. We now show that cultured Lyt-2- L3T4- T cells from lpr LN or normal thymus are very efficiently cytolytic toward not only allogeneic tumor targets, but also natural killer (NK)-susceptible targets and syngeneic targets. Such killing was not inhibited by antibodies to H-2 or Lyt-2. In contrast, cultured mature Lyt-2+ L3T4- T cells from normal LN, thymus, or lpr LN were cytolytic only toward allogeneic targets and were dependent on Lyt-2 expression and H-2 recognition. The similarities of cultured Lyt-2- L3T4- T cells to NK and lymphokine-activated killer cells are discussed.
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D007376:Interleukin-2 / Q000494:pharmacology; D008198:Lymph Nodes / Q000473:pathology*; D008222:Lymphokines / Q000378:metabolism; D008232:Lymphoproliferative Disorders / Q000235:genetics / Q000276:immunology; D051379:Mice; D008817:Mice, Mutant Strains / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D000950:Antigens, Ly; D007376:Interleukin-2; D008222:Lymphokines; D013755:Tetradecanoylphorbol Acetate