title: Low affinity E-rosette formation by the human K cell.
abstract: Human T lymphocytes were separated into two subsets on the basis of relative affinity for sheep red blood cells (E), and these T cell fractions were examined for cytotoxic reactivity against antibody-sensitized Change liver cells (ADCC). High affinity E-rosette-forming cells (E-RFC) (55 +/- 6% of peripheral blood mononuclear cells), capable of rosette formation despite elevated temperatures of incubation (29 degrees C) and a limited concentration of E, contained few antibody-dependent cytotoxic cells (K cells). In contrast, low affinity E-RFC (23+/-7% of mononuclear cell suspensions) requiring cool temperatures of incubation (4 degrees C) and an excess of E to form rosettes, were highly enriched for ADCC activity. The majority of K cells exhibited low affinity interactions with E. T cells in thymus, tonsil, and lymph node formed high affinity E-rosettes and exhibited little reactivity in ADCC. Only peripheral blood and spleen contained easily identified low affinity E-RFC and anti-body-dependent cytotoxic cells. The proportion of low affinity E-RFC in the peripheral blood of normal subjects correlated closely with reactivity in ADCC, making it possible to predict cytotoxic potential for the E-rosette pattern. These data indicate that the human K cell may belong to a previously unappreciated but functionally important subset of thymic dependent mononuclear cells.
mesh_terms: D000920:Antibody-Dependent Cell Cytotoxicity; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology; D014066:Palatine Tonsil / Q000276:immunology; D012397:Rosette Formation; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013696:Temperature; D013950:Thymus Gland / Q000276:immunology