Characterization of K-Cell Activity by Use of Depletion Experiments

Abstract

Normal human blood lymphocytes with affinity for ox red cells sensitized with IgG antibody, for normal or papain-treated sheep red cells and for ox red cells coated with mouse complement were used for rosette formation and the rosetting cells separated by density gradient centrifugation on Ficoll/Hypaque. The non-rosetting cells at the interface were collected and compared with cell suspensions before treatment for direct and antibody-dependent cytotoxicity of human target cells. Depletion of Fc-receptor-bearing lymphocytes strongly decreased antibody-dependent cell-mediated cytotoxicity; reduction in the number (or depletion) of T cells and cells with C′3 receptor had no effect, showing the same or enhanced K-cell activity. It is concluded that one type of K or killer cell has Fc receptors but lacks C′3 receptors.

Surface Characteristics of the Human K (Killer) Lymphocyte

“…In rodents, various T lymphocyte depletion procedures failed to modify K cell activity [Harding et ai, 1971;Van Boxel et al, 1972], Similarly, in man, depletion of T lymphocytes did not reduce K cell activity [Wisloff et al, 1974;De Bracco et al, 1976;Hersey et al, 1976;Kraft et al, 1976]; enrichment of T lymphocytes pro duced no change or a reduction of K cell ac tivity [De Bracco et al, 1976;Cordier et al, 1976;Hersey et al, 1976], Our present studies confirmed these findings. That a more obvious augmentation of K cell activity was not always observed (e .g.…”

“…In man, several studies have shown, that re moval of these cells on FicoII gradients pro duced no change in ADCC [De Bracco et al, 1976;Hcrsey et al, 1976;Kraft et al, 1976], but both Peter et al [1975] and Cordier et al [1976] found a reduction in ADCC. The latter, however, noted a mini mal change of K cell activity following their removal on a nylon column.…”

“…10 ml of the suspension of lymphocytes, ro settes and red blood cells were carefully layered onto a 10-ml column of Ficoll-Hypaque (SG 1.077) in a sterile polystyrene tube (90 X 24 mm) and spun in a stepwise manner; commencing at an interphase force of 200 g for 10 min, followed by 300 g for 10 min and finally at 450 g for 10 min [Kraft et al, 1976]. Two consecutive de pletion procedures were carried out to further de lineate a particular lymphocyte subpopulation.…”

“…derived [Van Boxel et al, 1972;Kraft et al, 1976] Fc-receptor-bearing lymphocyte [Wisloff et al, 1974;Ramshaw and Parish, 1976], but the presence or absence of sur face immunoglobulin (Smlg) [Press et al, 1974;Ramshaw and Parish, 1976] and re ceptors for complement (C3) [Perlmann et al, 1975b;De Bracco et al, 1976] on these cells has not been resolved.…”

Robin Coombs: his life and contribution to haematology and transfusion medicine

“…Using rosetting reactions to deplete and enrich specific lymphocyte subpopulations, Coombs and his colleagues were then able to test the various fractions obtained for their cytotoxicity against leucocytes sensitised with HLA antibody. They found that depletion of Fc -bearing cells reduced antibody-dependent cellular cytotoxicity (ADCC) suggesting that cytotoxic K cells had Fc receptors (Kraft et al, 1976). In a subsequent report they concluded that the PB NK cell was a non -T, Ig positive, Fc positive and complement receptor negative cell.…”