Activity of natural killer cells and granulocytes in peripheral blood and separated cells

: The natural killing of K 562 cells by whole blood from normal subjects was comparable with that shown by separated mononuclear cells. In order to establish the conditions for a reliable natural killer assay by using very small numbers of effector cells in whole blood, the isotope uptake of target cells was increased by a modified labelling method, which permitted the use of fewer target cells in the assay. The natural cytotoxicity of whole blood was augmented by interferon to the same extent as observed with separated mononuclear cells. The chemiluminescence of granulocytes in whole blood comparable with that of separated granulocytes. Taken together, these methods are considerably less tedious than the conventional methods, technique is also economical, and the results may reflect in vivo cytolytic processes much better.