Human killer cells and natural killer cells: distinct subpopulations of Fc receptor-bearing lymphocytes.
Unstimulated human peripheral blood lymphocytes were depleted of K cells, which mediate antibody-dependent cellular cytotoxicity (ADCC) without removing NK cells, which mediate natural killing (NK). K cell depletion was achieved by buoyant centrifugation removal of lymphocytes that bound to glutaraldehyde-treated P815-AB cells at high lymphocyte-to-target ratios. Likewise, NK cells were removed with glutaraldehyde-treated K562 cells without removing K cells. Furthermore, both cytotoxic cell populations were observed directly in one agarose single-cell cytotoxic assay (ASCA) using P815-AB and K562 cells simultaneously as target cells. Moreover, the percentage of total cytotoxic cells was equal to the sum of the percentage of K and NK cells observed in separate ASCA. Collectively, these results indicate that K cells and NK cells are distinct subsets of FcR-bearing lymphocytes. One subset, K cells, has more avid Fc receptors (fcR) than NK cells and are 'activated' via thier FcR to kill antibody-coated target cells. The second subset, NK cells, have less avid FcR and are not 'activated' through their FcR to kill antibody-coated target cells.
D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D001665:Binding Sites; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D003601:Cytotoxicity Tests, Immunologic; D005976:Glutaral / Q000494:pharmacology; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000276:immunology*; D008214:Lymphocytes / Q000145:classification* / Q000276:immunology; D011817:Rabbits; D011961:Receptors, Fc / Q000276:immunology*
D007106:Immune Sera; D011961:Receptors, Fc; D005976:Glutaral