LOW AFFINITY E-ROSETTE FORMATION BY HUMAN K-CELL

  • 1 January 1978
    • journal article
    • research article
    • Vol. 120  (1) , 90-95
Abstract
Human T [thymus-derived] lymphocytes were separated into 2 subsets on the basis of relative affinity for sheep red blood cells (E), then examined for cytotoxic reactivity against antibody-sensitized Chang [human] liver cells (ADCC [antibody-dependent cell-mediated cytotoxicity]. 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.degree. C) and a limited concentration of E, contained few antibody-dependent cytotoxic cells (K cells). Low affinity E-RFC (23 .+-. 7% of mononuclear cell suspensions) requiring cool temperatures of incubation (4.degree. 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 antibody-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 from the E-rosette pattern. The human K cell may belong to a previously unappreciated but functionally important subset of thymic dependent mononuclear cells.