Comparison of Interferon-gamma Secretion by Stimulated NK Cells and T cells from Healthy Subjects

ABSTRACT

Interferon-γ (IFN-γ) is an important cytokine produced by natural killer (NK) cells and T cells in response to various stimuli. The levels of IFN-γ secreted after stimulation of NK cells using a recombinant cytokine is represented as one of functions of NK cells. Recently, a method for evaluating NK cell activity in whole blood samples was developed. The levels of IFN-γ secreted after NK cell stimulation with PROMOCA™ (ATGen, Korea) and T cell stimulation with phytohemagglutinin (PHA) were compared using two different commercial kits: NK Vue Gold (ATGen, Korea) and QuantiFERON-TB Gold In-Tube (Cellestis, Australia). Participants included 43 healthy individuals. Whole blood samples were incubated with either PROMOCA, a recombinant cytokine that specifically activates NK cells, or with PHA. IFN-γ levels in the supernatants were measured by ELISA. The level of IFN-γ by PROMOCA stimulation (PROMOCA IFN-γ) was more varied than that by stimulation with PHA (PHA IFN-γ) (median 1,544.4 pg/mL [ range 193.7–2,530.9] vs. median 2,470.1 pg/mL [ 2,250.1–2,874.4] P=0.0001). The median of PHA IFN-γ/PROMOCA IFN-γ ratio was 1.9 (1.1–12.4). There was a significant difference in levels of IFN-γ secreted after stimulation with PROMOCA or PHA in the healthy population.