前列腺素E_2对Th1/Th2和Tc1/Tc2淋巴细胞免疫平衡的调节

Regulation of Immunological Balance Between Th1/Th2 and Tc1/Tc2 Lymphocytes by Prostaglandin E_2

本研究探讨前列腺素E2(PGE2)对外周血T淋巴细胞体外增殖的影响,以及对Th1/Th2和Tc1/Tc2细胞的免疫平衡的调节作用。不同浓度PGE2与抗CD3和抗CD28单克隆抗体(mAb)和健康成人外周血单个核细胞(MNC)共同培养120小时,测定细胞增殖程度。ELISA方法测定24、48、72和120小时细胞培养上清液中IFN-γ和IL-4浓度变化。流式细胞仪测定CD4+IL-4+T细胞和CD4+IFN-γ+T细胞以及CD8+IL-4+T细胞和CD8+IFN-γ+T细胞比值。各实验均以不加PGE2为对照。结果表明:①随PGE2的浓度增加,T细胞体外增殖的抑制率明显增高(p=0.001);T细胞增殖抑制率与PGE2浓度之间呈明显的正相关(r=0.889,p=0.000)。②实验组培养120小时的IFN-γ浓度与第72小时的IFN-γ浓度差异无显著性(p=0.917),对照组细胞培养上清液中的IFN-γ浓度随时间持续增高(p=0.046);实验组不同时间的IFN-γ浓度均明显低于对照组(p<0.05)。实验组在不同时间产生IL-4浓度无明显变化(p=0.400);对照组24小时细胞培养上清中IL-4浓度高于48、72和120小时(p值分别为0.007、0.003和0.002);实验组细胞培养24小时时IL-4浓度明显低于对照组(p=0.037);实验组细胞培养48、72和120小时与对照组IL-4浓度差异无显著性(p>0.05)。③实验组与对照组CD4+IFN-γ+T细胞的比例无明显变化(p=0.767);实验组CD4+IL-4+T细胞比例略高于对照组(p=0.051);实验组CD4+IL-4+T细胞与CD4+IFN-γ+T细胞的比值明显高于对照组(p=0.011)。实验组与对照组CD8+IFN-γ+T细胞的比例无明显变化(p=0.441);实验组CD8+IL-4+T细胞的比例明显高于对照组(p=0.015);实验组CD8+IL-4+T细胞与CD8+IFN-γ+T细胞的比值明显高于对照组(p=0.038)。结论:PGE2体外抑制外周血T细胞的增殖;PGE2作用24小时即可抑制IFN-γ和IL-4的产生,并且明显影响T细胞IFN-γ的高峰出现,对IFN-γ具有持续性的抑制作用,对IL-4的持续性影响并不明显;PGE2使CD4+IL-4+T细胞与CD4+IFN-γ+T细胞的比值和CD8+IL-4+T细胞与CD8+IFN-γ+T细胞的比值增加,调节T细胞的免疫反应向Th2/Tc2方向发展。

This study was purposed to investigate the effect of prostaglandin E2 （ PGE2 ） on proliferation of peripheral blood T lymphocytes, and to evaluate the regulatory role of PGE2 on immunological balance between Thl/Th2 and Tcl/ Tc2 lymphocytes. The peripheral blood mononuclear cells （PBMNC） were stimulated by anti-human CD3 monoclonal antibody （mAb） and anti-human CD28 mAb, and were cultured in the presence of different concentration of PGE2 for 120 hours. The proliferation of peripheral blood T lymphocytes was assayed according to the manufacture protocol of BrdU Kit; the/FN-γ, and IL-4 levels in supematants cultured for 24, 48, 72 and 120 hours were detected by ELISA; the ratios of CD4^＋ IL-4^＋ T cells/CD4 ＋ IFN-γ T cells and CD8^＋ IL-4^＋ T cell/CD8^＋ IFN-γ ＋ T cells were determined by flow cytometry. The cells cultured without PGE2 were used as control. The results indicated that （ 1 ） with the raising of concentration of PGE2, the inhibitory rate of T cell proliferation in vitro significantly increased （p =0. 001 ）. There was significant positive correlation between inhibitory rate of T ceils and PGE2 concentration （ correlation coefficient = 0.889, p =0.000）. （2） the difference between the IFN-γ concentrations in supematant cultured for 120 and 72 hours in test groups had no statistical significance （p = 0. 917 ）. The IFN-γ concentration increased continually with prolonging of culture time in control group （p = 0. 046 ）. The IFN-γ concentrations produced at different times in test group were significantly lower compared with those in control group（p 〈 0.05）. The IL-4 concentrations produced at different time had no significant change in test groups （p = 0. 400）. The IL-4 concentration in 24 hours in control group was significantly higher than that at 48, 72 and 120 hours in control group （p =0.007, 0.003 and 0. 002）. After cultured for 24 hours the IL-4 concentration in test group was significantly lower than that in control group （p = 0. 037 ）, but after cultured for 48, 72 and 120 hours, the IL-4 concentration in test group did not show statistical difference in comparison with control group （p 〉 0.05 ）. （ 3 ） the proportions of CD4^＋ IFN-γ T cells in test group and in control group had no significant difference （p = 0. 767）. The proportion of CD4 IL-4 ＋T cells in test group was slightly higher than that in control group （p =0.051）. The ratio of CD4~ IL-4~ T ceils to CD4~ IFN-γ T cells in test group was significantly higher than that in control group （p = 0. 011 ）. The proportions of CD8^＋ IFN-γ T cells in test group and in control group had no statistical difference （p = 0.441 ）. The proportion of CD8^＋ IL-4^＋ T cells in test group was significantly higher than that in control group （p = 0. 015）. The ratio of CD8^＋ IL-4^＋ T cells to CD8^＋ IFN-γT cells in test group were obviously higher than that in control group（ p = 0.038 ）. It is concluded that the PGE2 inhibits the proliferation of T lymphocytes in vitro. PGE2 influences the production of IFN-γ and IL-4, and significantly influences peak appearance of IFN-γ produced by T lymphocyte. PGE2 can continuosly inhibit the production of IFN-γ, but its continuous effect on IL- 4 is no significant. PGE2 enhances the ratio of CD4^＋ IL-4 ＋ T lymphocytes to CD4^＋ IFN-γ T lymphocytes and the ratio of CD8^＋ IL-4^＋ T lymphocytes to CD8^＋ IFN-γ T lymphocytes, and regulates development of T cells toward Th2/Tc2 cells.