RESUMEN
Objective To study tumor immune escape in a gastric carcinoma cell line expressing human indoleamine 2,3-dioxygenase(IDO).Methods Human IDO gene was cloned by RT-PCR and the vector for pIRES_2-EGFP-IDO was constructed.BGC-823 cells were transfected with the plasmid using eleetroporation.The integrated INDO genes were detected by RT-PCR and Western blot.The enzyme activity of IDO were measured.T cells from gastric cancer patients were cecuhured with BGC-823 transfected with IDO or added with 1-MT circumstance,T cell-mediated cytotoxicity and proliferation were detected.Results Higher level expression of IDO mRNA and IDO protein Was detected in tumor cells transfected with IDO gene.The level of kynurenic acid was higher in transfected cells compared with no-transfeeted group (4.84±0.11)mg/L vs.(1.83±0.10)mg/L,P=0.000.The cytotoxicity ratio of the IDO transfected group and transfected group with 1-MT circumstance (1-MT group) was lower than control group (P<0.05).The inhibition rate of transfected group with 1-MT group Was higher than control group(P<0.05).Conclusion Gastric cancer cell lines encoded with IDO inhibits T cell-mediated cytotoxicity and proliferation.