A Modified NK Cell Degranulation Assay Applicable for Routine Evaluation of NK Cell Function

Figure 1

Comparison of conventional degranulation assay with modified assay. Whole blood was incubated with fluorescein isothiocyanate-conjugated antiCD107a antibody alone or with PMA + Ca²⁺-ionophore or K562 cells for 2 h (as three separate samples). Samples were analyzed by flow cytometry, gating on lymphocytes by forward/side scatter. CD107a expression was analyzed on natural killer (NK) cells (CD56⁺CD3⁻), (a) and the increase in % CD107a⁺ NK cells between unstimulated and stimulated samples was calculated. Results were considered valid if the healthy control sample processed along with the patient sample gave normal results. Patient results were considered abnormal if the increase was <10% on stimulation. Flow cytometry figures represent the percent NK cells that express CD107a following no stimulation (b) and stimulation with K562 cells (c) or with PMA + Ca²⁺-ionophore (d) in a single representative subject. The dot plot represents the percent NK cells that express CD107a following no stimulation and stimulation with K562 cells or PMA + Ca²⁺-ionophore for all subjects tested in this study (e).

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(b)

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(e)