title: Characteristics of mouse thymocyte-derived, interleukin 2-activated killer cells and their precursors.
abstract: Culture of hydrocortisone (HC)-resistant C57BL/6 mouse thymocytes with recombinant human interleukin 2 (IL 2) allowed the proliferation of the thymocytes and resulted in the generation of lymphokine-activated killer (LAK) cells cytotoxic to a variety of tumor cells. The cytotoxic activity of the LAK cells was greatly reduced by treatment with anti-Thy 1.2 or anti-Lyt 2.2 monoclonal antibody and complement but not with anti-asialoGM1 antibody plus complement. Fractionation of IL 2-stimulated thymocytes by means of Percoll density gradient centrifugation revealed that both cytotoxic activity and binding capacity to target cells were greater in the cells with lower density and larger size than in the cells with higher density and smaller size. These IL 2-activated thymocytes expressed higher levels of both Thy 1, Lyt 2 and lymphokine-activated cell-associated (LAA) antigens than unstimulated thymocytes, as indicated by a flow cytometric analysis. The frequency of LAK precursor cells was found to be 7.5 times greater in the HC-resistant thymocyte population than in total thymocytes, as determined by means of a limiting dilution method. The LAK precursor cells in HC-resistant thymocytes appeared to be Lyt1- (or dull Lyt 1+), L3T4-, Lyt 2-, asialoGM1-T cells, because elimination of bright Lyt 1+, Lyt 2+ or L3T4+ T cells from HC-resistant thymocytes had no effect on the generation of LAK cells. These results indicate that LAK cells from mouse thymocytes are Lyt 2+ T cells which are inducible from HC-resistant Lyt 2- thymocytes.
mesh_terms: D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects; D004351:Drug Resistance; D005434:Flow Cytometry; D006854:Hydrocortisone / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010641:Phenotype; D011994:Recombinant Proteins / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D007376:Interleukin-2; D011994:Recombinant Proteins; D006854:Hydrocortisone