Abstract: AIMTo study the effect of prothymosin α (Pro Tα) as a fusion protein on secretion of IFN-γ, IFN-α and TNF-α in vitro. METHODSThe in vitro study was carried out on the culture of splenocytes,splenic and peritoneal macrophages isolated from Balb/c mice. Splenocytes were incubated with various concentrations of Pro Tα (1×10^-7～1×10^-10 mol·L^-1) with or without Con A (5 μg·mL^-1) for 72 h. Splenic and peritoneal macrophages were respectively treated with Pro Tα (1×10^-7～1×10^-10 mol·L^-1) in the presence of LPS (10 μg·mL^-1) for 24 h. Then IFN-γ, IFN-α and TNF-α levels in the supernatant were detected by ELISA. RESULTSPro Tα (1×10^-7 mol·L^-1) was found to obviously increase IFN-γ level (P<0.05) in the supernatant of splenocytes compared with the control group. Moreover, Pro Tα (1×10^-7 mol·L^-1) significantly induced the secretion of IFN-α (P<0.01) and TNF-α (P<0.01) in splenic and peritoneal macrophages. CONCLUSIONin vitro, Pro Tα could increase the secretion of IFN-γ, IFN-α and TNF-α.