title: Helper cell-independent clonal expansion of H-2D-restricted cytolytic T cells.
abstract: Cytotoxic T lymphocyte (CTL) clones of different phenotypes have been described: some need extrinsic growth factors for proliferation whereas others can be expanded by antigenic stimulation. Up to 40% of CTL clones obtained early during in vitro culture can be stimulated by antigen in the absence of extrinsic interleukin 2 (IL 2) whereas all late clones require exogenous IL 2. Early clones regularly change their phenotype, i.e., their growth becomes dependent on exogenous IL 2. We propose that the growth of Lyt-2+ cells restricted by class I major histocompatibility complex (MHC) antigen is essentially independent of growth factors produced by class II MHC antigen-restricted T helper cells but can be augmented by such factors, especially at later stages of antigen-induced differentiation.
mesh_terms: D000818:Animals; D000950:Antigens, Ly; D002455:Cell Division; D002999:Clone Cells / Q000276:immunology; D005802:Genes, MHC Class II; D006183:H-2 Antigens / Q000276:immunology; D008211:Lymphocyte Cooperation; D008285:Major Histocompatibility Complex; D008297:Male; D051379:Mice; D012737:Sex Factors; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000950:Antigens, Ly; D006183:H-2 Antigens