title: Functional analysis of cloned germinal center CD4+ cells with natural killer cell-related features. Divergence from typical T helper cells.
abstract: Granular lymphocytes co-expressing the Leu-7 (NK-related) and CD4 (T helper cell) markers are selectively localized in the germinal centers of lymphoid tissues. Leu-7+ cells (greater than 98% of which co-expressed CD4) were isolated from inflammatory tonsils and were cloned by the limiting dilution technique. Clones were analyzed for their phenotypic and functional characteristics. CD4+-Leu-7+ cell-derived clones retained their CD3 and CD4 surface antigens, lost the Leu-7 marker, and acquired HLA-DR determinants. In comparison with clones derived from peripheral blood or tonsil CD4+ cells, CD4+-Leu-7+ tonsil cell-derived clones showed similar low frequencies of cytotoxic precursors. In contrast, the frequency of interleukin 2 (IL 2) and B cell growth factor producing clones was much lower for tonsil CD4+-Leu-7+ cells than for CD4+ blood or tonsil progenitors. We conclude that germinal center CD4+-Leu-7+ cells are a subset of T cells unable to produce IL 2 in response to phytohemagglutinin or anti-CD3 stimulation, which is effective on the majority of T helper cells.
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D002454:Cell Differentiation; D002999:Clone Cells / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D006133:Growth Substances / Q000096:biosynthesis; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4; D007694:Killer Cells, Natural / Q000145:classification* / Q000276:immunology; D008222:Lymphokines / Q000096:biosynthesis; D014066:Palatine Tonsil / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000145:classification / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D006133:Growth Substances; D007376:Interleukin-2; D008222:Lymphokines; D015847:Interleukin-4