Abstract
A new cytotoxicity assay was developed to measure Natural Killer cell activity. This assay does not need 51Cr labelled target cells. FITC (Fluorescein Isothiocyanate) was used for labelling of target cells, K 562, in acidic conditioned medium. Target cells were coincubated with peripheral blood mononuclear cells in plastic tubes. After 4 hours incubation, these cells were resuspended in a Fuchs-Rosenthal chamber.
Then these mononuclear-cells and target cells were counted by NIKON epifluorescent microscope.
Only alived target cells glittered and it was easy to distinguish alived target cells from mononuclear cells. NK cell activities measured by this new assay had very high correlation (r=0.887 p<0.001) with standard 51Cr release assay.
