目的　对本室克隆并表达的一种胸腺素α原 (humanprothymosinα ,ProTα)的生物活性进行体外实验研究。 方法　体外对其促进E 玫瑰花结形成率 ,在ConA存在下及单独使用ProTα对小鼠胸腺细胞的促增殖作用 ,以及对细胞活素IL 2 ,IFN γ的促诱生作用进行检测。结果　在高浓度时 (1× 10 -7mol·L-1) ,对人外周血单核细胞E 玫瑰花结形成的激活率可达 5 2 .7%。无论有无ConA ,1× 10 -7,1× 10 -8mol·L-1的ProTα明显刺激小鼠胸腺细胞增殖 (P <0 .0 1) ;此外 ,一定浓度的ProTα能促进IL 2 ,IFN γ的分泌 (P <0 .0 5 )。结论　ProTα具有明显刺激小鼠胸腺细胞增殖和促进IL 2 ,IFN γ分泌的生物活性 Objective To investigate the biological activity of a human prothymosin α (ProTα) cloned and expressed in our laboratory. Methods The rate of E-rosette formation in vitro, the effect of ProTα on proliferation of mouse thymocytes and the pro-inducible effect of cytokines IL-2 and IFN-γ were detected in vitro. Results At high concentration (1 × 10 -7 mol·L-1), the activation rate of E-rosette on human peripheral blood monocytes was 52.7%. ProTα (1 × 10 -7, 1 × 10 -8 mol·L -1) significantly stimulated thymocyte proliferation in mice with or without ConA (P <0.01). In addition, certain concentrations of ProTα promoted IL 2, IFN γ secretion (P <0.05). Conclusion ProTα can significantly stimulate the proliferation of mouse thymocytes and promote the biological activity of IL 2 and IFN γ secretion