THE EXPRESSION AND ENHANCEMENT OF CO-STIMULATORY MOLECULE (B7-1, B7-2) IN GASTRO-INTESTINAL CANCER.

共刺激分子（B7-1, B7-2）已被证明在诱导T细胞介导的抗肿瘤免疫中起重要作用。本研究通过逆转录酶/聚合酶链式反应（RT-PCR）检测了B7-1和B7-2在人食管癌、胃癌和结肠癌细胞系中的mRNA表达水平，并通过单克隆抗体流式细胞术检测了它们的表面表达。B7-1或B7-2 mRNA在18个细胞系中均有表达，B7-2 mRNA仅在1个细胞系中表达。其中13个（72%）或12个（67%）细胞表达B7-1或B7-2表面抗原，分别用单克隆抗体检测。在干扰素- γ (IFN-g)培养后，6个细胞系中有4到5个细胞系的B7-1或B7-2的表面表达增加。此外，IFN-g上调B7-1或B7-2的表达被白细胞介素-10 （IL-10）抑制。这些结果表明，在胃肠道癌来源的细胞系中，大多数细胞系在mRNA和蛋白水平上均可检测到B7-1和B7-2共刺激分子，并可通过细胞因子IFN-g和IL-10进行调节。

The co-stimulatory molecule (B7-1, B7-2) has been shown to play an important role in the induction of T cell mediated immunity against tumors. In the present study, we examined the expression of B7-1 and B7-2 in the human esophageal, gastric and colon cancer cell lines for mRNA level by a reverse transcriptase/polymerase chain reaction analysis (RT-PCR), for their surface expression by a flow-cytometric analysis with monoclonal antibodies. The expression of mRNA for B7-1 or B7-2 was detected in all 18 cell lines tested, except for B7-2 on one cell line. The cells from 13 (72%) or 12 (67%) of these cell lines expressed the surface B7-1 or B7-2 antigen, detected with respective mAb. The surface expression of B7-1 or B7-2 was increased in four to five of the six cell lines tested after a culture with interferon-gamma (IFN-g). In addition, the up-regulation of B7-1 or B7-2 expression by IFN-g was inhibited by interleukin-10 (IL-10). These results indicated that, in the cell lines derived from gastrointestinal carcinoma, both the co-stimulatory molecules B7-1 and B7-2 were detectable in the majority of the cell lines examined at the mRNA and protein levels, and could be regulated with cytokine IFN-g and IL-10.