超抗原SEB的免疫抑制作用及其机制的初步研究

Immunity suppressive effect and possible mechanism of SEB as a superantigen

目的研究金黄色葡萄球菌肠毒素SEB作为超抗原的免疫抑制性作用及其可能机制。方法BALB/c小鼠注射金黄色葡萄球菌B型肠毒素(staphylococcal enterotoxin B,SEB),分离其脾脏细胞,研究SEB刺激小鼠脾细胞产生的反应,并通过FCM检测脾细胞表面CD4和CD25分子的表达情况,探讨其内在机制。结果FCM表明与生理盐水对照组相比,注射过SEB后的BALB/c小鼠的脾脏细胞中CD4和CD25双阳性细胞比例增加,提示SEB的免疫抑制作用可能和其诱导调节性T细胞有关。结论SEB可以在小鼠体内有效诱发具有抑制活性的调节性细胞,这可能是SEB在动物体内诱发免疫低反应的机制之一。

Objective To study the immunity suppressive effect of the staphylococcal enterotoxin as a super-antigen and investigate its mechanism. Methods BALB/c mice aged 8-12 weeks were randomly assigned to receive 0.2 ml injection of 50 μg/ml staphylococcal enterotoxin B （SEB） （ n = 20） or 0. 2 ml physiological saline （n =20）. One day later, all mice were sacrifice to collect the splenoeytes which were employed to detect the expression of TGF-[31 and to eountthe cells expressing CD4 and CD25 by flow eytometry （FCM）. Results FMC showed that a remarkable increase of cells that expressed CD4 and CD25 in the SEB-primed splenoeytes as compared with the saline primed splenocytes. Conclusion SEB, which is used as a superantigen in vivo, can induce the regulatory cells bearing suppressive activity. This may be partial mechanism of SEB-induced hyporesponsiveness.