title: Surface markers and functional characteristics of human blood lymphocytes residing in the operational "null" subset.
abstract: After removal of nylon wool-adherent B and E rosetting T cells from the human blood lymphocyte population, a small fraction remains, often denoted as "null" subset. This fraction contains lymphocytes which are highly efficient in antibody-dependent and non-selective lymphocyte cytotoxicity. These cells possess markers. About half of them carry Fc receptors, and the majority has low avidity E and C3 receptors. Removal of low avidity E receptor-carrying cells did not abolish cytotoxicity to K-562 cells. The majority of cells carry receptors for Epstein-Barr virus but cannot be infected. The cells in mixed lymphocyte culture have a low reactivity. They aare stimulated by PHA and ConA to a similar extent and differ from the cells which readily sediment as E rosettes: these respond stronger to PHA. The "null" fraction may contain stem cells common for both T and B lineages.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002417:Cattle; D002462:Cell Membrane / Q000276:immunology; D003165:Complement System Proteins / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D004912:Erythrocytes / Q000276:immunology; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000145:classification / Q000276:immunology*; D008934:Mitogens / Q000494:pharmacology; D011961:Receptors, Fc; D012397:Rosette Formation; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D008934:Mitogens; D011961:Receptors, Fc; D003165:Complement System Proteins