中文摘要：

为研究绵羊接种布鲁氏菌弱毒M5．90株后外周血中CD4^＋、CD8^＋T、CD4^＋CD2YTreg细胞的动态变化规律，本研究选择11只健康绵羊，每10d免疫一次，共免疫3次，分别在免疫前、免疫后10d、20d、30d利用流式细胞术检测外周血中CD4^＋、CD81、CD4^＋CD25^＋Treg淋巴细胞亚群。在免疫后的第20d，CD4^＋T、CD8^＋T细胞百分含量达到最高水平（p〈0．05）后均缓慢下降；在第10d，CD4^＋CD25^＋Treg细胞缓慢升高，至20d、30d均显著升高（p〈0．05）；在布鲁氏菌M5-90疫苗免疫应答过程中CD4^＋CD25^＋Treg细胞参与了机体的免疫反应调控，对CD4^＋T、CD8^＋T淋巴细胞的比例进行调节，并且维持CD4^＋／CD8^＋比值稳定，起到平衡Th1／Th2细胞间反应的作用。

英文摘要：

To explore the dynamic change and relativity of CD4＋CD25＋ regulatory T cells, CD4＋, CD8＋, CD25＋ T lymphocyte subgroup and CD4＋/CD8^＋ in peripheral blood of the sheep inoculated with Brucella vaccine M5-90. Eleven healthy sheep were vaccinated three times at 10-days interval. CD4＋CD25＋ regulatory T cells, CD4＋, CD8＋, and CD25＋ T lymphocyte subgroup in peripheral blood was detected at 0, 10, 20, and 30 days post vaccination （PI）, respectively. The results showed that the CD4＋, CD8^＋, CD25＋ T cells changed slowly in varying degrees at 10 days PI, without significant difference, but it was increased significantly （p〈0.05） at 20 and 30 days PI, Treg cells were consistently increased, and on 20 and 30 days, with significant difference （p〈0.05）. However, the CD4＋/CD8^＋ ratio remained at about 1.49. In conclusion, Treg cells might be involved in immune response regulation in the Brucella infection process. It might inhibit the proliferation of CD4＋, CD8^＋T lymphocyte, maintain the stability of CD4＋/CD8^＋ ratio, and balance the cell reaction between Thl and Th2. However, the specific mechanism of action in the course of Brucella infection requires further study.