激发型CD28单抗直接激发的T细胞及其表型

The T Cells Directly Activated by the Agonist CD28 Monoclonal Antibody and Its Epitopes

1.用羊抗鼠IgG(20 μg/ml)包被96孔细胞培养板,再加入游离的激发型GD28单抗(终浓度为5 μg/ml);2.用激发型CD28单抗(10μg/ml)直接包被96孔细胞培养板,然后分别加入105个/孔经E-花结实验获取的人外周血T细胞(PBTC),其中CD3+T＞95%.逐日观察细胞的生长状态并绘制生长曲线,用3H-TdR掺入法分析PBTC的增殖效应,用FITC标记的单抗经流式细胞仪(FCM)分析细胞CD3、CD4、CD8、CTLA-4、4-1BB及OX40的表达.逐日细胞计数的结果表明,经羊抗鼠IgG包被后加入游离激发型CD28单抗或直接用激发型CD28单抗包被,均能引发PBTC的活化与增殖效应,激发3 d时的刺激指数(SI)大于9,细胞CD3、CD4、CD8、CTLA-4、4-1BB及OX40的阳性表达率(x±s,%)分别为98.6±0.2、74.4±3.1、22.5±2.0、2.1±0.4、18.4±2.2、35.2±3.5.与XGB7(作为APC)刺激的T细胞相比,经CD28单抗直接激发的T细胞,CD4+/CD8+T细胞的比值及OX40+T细胞的百分率升高(P＜0.01),但不表达负性调节分子CTLA-4.

The aim of this study is to investigate the T cell activation, proliferative effect and the phenotypic characteristics of the proliferative cells induced through the direct coupling of the agonist CD28 monoclonal antibodies with CD28 molecules on T cells on the basis of 5 mouse anti human CD28 monoclonal antibodies. The proliferative responses of T cells were determined by 3H-TdR incorporation assay and the analysis of epitopes on peripheral blood T cells was undertaken with flow cytometry. Experimental results showed that agonist CD28 monoclonal antibodies could activate and induce proliferation of the peripheral blood T cells directly with stimulatory index (SI )of more than 9. The percentages of expression of CDS, CD4, CD8, CTLA-4, 4-1BB and 0X40 positive cells on the peripheral blood T cells were 98.6±0.2, 74.4±3.1, 22.5 ±2.0, 2.1±0.4, 18.4±2.2 and 35.2±3.5 respectively. In comparison with the agonist cell line XGB7 (acts as antigen presenting cells ) , the perventages of agonist CD28 monoclonal antibody stimulated T cell. The ratio of CD4 + /CD8+ T cells as well as the percentage of 0X40 positive cells were increased, but no expression of the down-regulated molecule CTLA-4. It concludes that the agonist CD28 monoclonal antibody may be significant value in the basic studies and clinical applications in adoptive immunity of tumors.