Natural Killer Cell Cytotoxicity: A Methods Analysis of Versus Flow Cytometry Chromium Release

Abstract

The purpose of this study is to describe design considerations for the use of flow cytometry (FC) com-pared to51 chromium (51 Cr)-release assays utilizing cryopreserved peripheral blood mononuclear cells (PBMCs) to detect natural killer (NK) cell cytotoxicity. Subjects were 10 healthy women aged 18 to 39 years. Intra-assay variability between methods differed only at the lowest effector-target ratios evaluated. Interassay variability was wide but did not differ between methods. The relationship of lytic unit-10 between methods was strongly positive. Cytotoxicity detected by51 Cr release was higher than that detected by FC for all 10 subjects. Cost was comparable. How-ever, had more assays been performed, technician time would have been greater with flow cytometry. More whole blood was needed to perform the flow cytometry cytotoxicity assay than51 Cr-release cytotoxicity assay. The authors found no compelling reason to adopt NK cell cytotoxicity by flow cytometry over51 Cr release.