Interferon gamma (IFN-γ) production by peripheral blood mononuclear cells (PBMC) stimulated with recombinant canine IL-2 and/or IL-12 produced by COS-7 cells. PBMC of 8 adult mongrel dogs were cultured for 48 h with: a) complete RPMI 1640 medium alone (M), b) supernatant of COS-7 cells transfected with pcDNA3.1-caIL-2 (SN IL-2) at 0, 0.2, 1, 5 or 25% in combination with supernatant of COS-7 cells transfected with pcDNA3.1-sccaIL-12 at 0.025 (A), 0.5 (B) or 10% (C). IFN-γ was assessed in the PBMC supernatants by capture ELISA. Data represent average of duplicates and bars the means obtained for the eight animals. *p < 0.05, **p < 0.01; Dunnett’s test (p < 0.0001, repeated measures ANOVA).