本研究在探討太極拳運動(Tai Chi Chuan ,TCC)對老年人在抑制B型肝炎病毒免疫作用上是否較對照組(sedentary controls ,SC)有較強的免疫反應，太極拳運動VO2 peak最高峰可達到45.83%，HR max可達到64.93%，因此認為太極拳對於老年人是屬於一種有氧之中低強度運動。實驗方法採用植物血球凝集素(phytohaem- agglutinin , PHA)刺激作用後的人類週邊血液單核球細胞加入可表現B型肝炎毒的Hep3B細胞培養基下，觀察其免疫抑制情形。經由實驗控制後的結果發現在相同濃度的PHA(5μg/ml)刺激之下，檢測兩者對於抑制B型肝炎病毒表面抗原作用的表現，其中TCC組為68.4%，而SC組為84.3%，細胞激素(Cytokine) IFN-γ，TNF-α和IFN-α，在培養基的表現情形，具有運動習慣之TCC組較優於SC組。結論：太極拳運動對老年人在抑制B型肝炎病毒免疫作用上較正常無運動習慣的老年人有較強的免疫反應。

　　Whether middle-aged people with Tai Chi Chuan(TCC) exercise, at medium intensity, have higher immunity against hepatitis B virus than sedentary controls(SC). We prepared conditioned media (MNC-CM) by stimulating the human peripheral blood mononuclear cells with phytohemagglutinin (PHA) for assessment of the inhibitory effects on hepatitis B surface antigen (HBsAg) expression in human hepatoma Hep3B cells. Results : The % HRmax at about 64.93 % and % VO2 peak at about 45.83 % indicates that the TCC exercise might be defined as an aerobic and moderate exercise. The inhibitory effect of TCC group’ MNC-CM against the HBsAg expression was greater than that of SC group. Comparing with the same stimulating concentration of PHA (at 5 μg/ml), the relative HBsAg expression of TCC group MNC-CM was 68.4 % versus 84.3 % of SC group. The amounts of secreted cytokines such as TNF-α, IFN-γ and IFN-α, were greater in the MNC-CM from the TCC group than those in the SC group. Results of cytokine neutralization suggest that various cytokines may play a role for inhibitory effect of TCC-MNC-CM against HBsAg expression. Conclusion : The results indicate that the immune response of MNC, after being stimulated with PHA, to suppress HBsAg expression in middle-aged people with Tai Chi Chuan exercise is greater than that in sedentary controls.