Characterization of natural killer (NK) cells and killer (K) cells in human blood: Discrimination between NK and K cell activities

Abstract

Cell suspensions enriched and depleted for rosette-forming cells with sheep red blood cells (E-RFC) and depleted for RFC with antibody complexes were prepared. The isolated fractions were characterized by cell surface marker analysis and tested for their natural killer (NK) and killer (K) cell activity against K-5 62 cells and IgG-coated P-8 15 cells, growing in suspension, and against a number of monolayer tumor cell lines. It was found that the NK cells most likely belong t o the T cell lymphocyte subpopulation. Furthermore, this study indicates that several subpopulations exist, e.g. NK cells that have no IgG F c receptor (FcR) on their surface and NK cells that bear IgG FcR, indicating that for a proportion of NK cells the IgG FcR is not involved in the NK lytic process and hence antibody-independent. Moreover, monocytes and B lymphocytes appear not t o be directly involved in the NK cell lytic process.Furthermore, cell separation procedures were used t o obtain cell suspensions either bearing IgG FcR or lacking IgG FcR. Cells bearing IgG FcR were isolated in such a way that they lost their IgG FcR by shedding, as a result of the separation procedure. Again, all fractions were simultaneously characterized by cell surface marker analysis and tested for their NK and K cell lytic activity. The effect of immune complexes on the NK and K cell lytic activities was investigated. The data indicate that the IgG FcR is not involved in the NK lytic mechanism, although this receptor may be present o n the NK cell. Moreover, prolonged culturing of lymphocytes increases and/or induces NK cell lytic activity.

Enhancement of NK, but not K Cell Activity by Different Interferons

“…Recent data pre sent evidence that NK and K cell activity can be dissociated if parameters other than cell separation techniques are used, e.g., in volvement of Fc receptors [3] or treatment with cortisone [17] . Our data showing dif ferent susceptibility to interferons provide further evidence that NK and K cell activi ties represent different effector mechanisms in cell-mediated cytotoxicity.…”

Cytotoxicity of Temporarily Adherent Human Mononuclear Blood Cells in Monocyte Monolayers

“…K cell activity has been claimed to be due to NK cells [13][14][15][16] although some information suggests that K cells and NK cells may be different cell types [17][18][19], Among the detached, initially ad herent cells 45% stained positively with OKT 10, which is known to stain human N K cells [6], Monocytes mediate ADCC [20], Among the tem porarily adherent cells there are 10% monocytes [4], but these monocytes can hardly be responsible for all the ADCC effect observed, as the detached cells were more potent than adherent monocytes in ADCC.…”

Immune Response against Vaccinia Virus in Rhesus Monkeys: No Evidence for Primary MHC-Restricted Cytolytic T Cells

“…the effector mechanism experiments shown in table V were performed. Neither treatment of effector cells with anti-F(ab')2, nor with oval bumin-anti-ovalbumin complexes to satu rate the IgG-Fc receptors on the effector cells, nor with protein A to inhibit binding of the target cells coated with IgG to the Fc recep tor-positive cells [5] resulted in significant inhibition of cytotoxicity. On the contrary, treatment with protein A in vitro resulted in a slight increase of cytotoxicity.…”