Fig. 6

Effects of IL-21 stimulation on ADCC activity and interferon (IFN)-γ production of cultured canine NK cells. To determine the capacity of additional IL-21 stimulation on the enhancement of effector function, cultured NK cells were additionally treated with rcIL-21 for 2 days prior to harvest (additional IL-21), and the cytotoxicity and IFN-γ production against trastuzumab-coated SKBR3 cells were compared with cultured NK cells without additional IL-21 stimulation (NK). a The 4-h cytotoxicities of NK cells against SKBR3 cells pretreated with trastuzumab were measured at a 4:1 E:T ratio. The cytotoxicity of NK cells against SKBR3 cells pretreated with media alone (Control) or the human isotype IgG antibody (Isotype) served as the controls. The median, first (Q1) and third (Q3) quartiles, and the minimum and maximum are shown from triplicate reactions and five different donors. b Production of IFN-γ in cultured NK cells in response to SKBR3 pretreated with trastuzumab. IFN-γ production was assessed in the culture supernatants by ELISA. Control conditions consisted of the culture supernatant from SKBR3 cells (SKBR3 only), NK cells cultured alone (NK only), or NK cells cultured with SKBR3 cells with (Isotype) or without (Control) pretreatment of human IgG isotype antibody. The results are shown as means ± standard deviation (SD) from triplicate reactions and four different donors. *p < 0.05, **p < 0.01