Study Of Tumor-host Interaction In Patients With Gastric Cancer:analysis Of In Vivo Local Cytokines Expression And The T Cell Receptor Repertoire

Gastric cancer is one of the most common cancers in Asian countries and the top killer cancer in our country. Surgery alone or combined with chemotherapy is the main treatment modality. Unfortunately, the efficacy is often disappointing, especially in advanced stage gastric cancer. New therapeutic strategies are required. Recent studies show that the tumor infiltrating T lymphocytes (TILs) isolated from some tumor patients can react with tumor-associated antigen and some of them can lyse tumor cells specifically. From those findings, an attractive approach is to develop cancer vaccine and cancer adoptive immunotherapy, thus restores or elicits an effective antitumor immune response. A few studies on gastric cancer immunotherapy demonstrated some promising results. However, there had been little studies on the immune interaction between tumor and host in gastric cancer patients in vivo. The mechanisms by which tumor cells elicit an immune response 6 but finally escape from detection or destruction by the host immune system remains poorly understood. Such information is important in guiding the approaches of immunotherapy. Cytokines play a central regulatory role in host immune response and may have an influence on tumor growth. Identification of the local cytokine profile may provide clues on host-immune interaction in patients with gastric cancer and may be helpful in immunotherapy. Lymphocytes enriched in I cells infiltration of cancer tissue suggests a local host immune response against autologous tumor. Detailed analysis of effector mechanism involved in tumor rejection revealed an essential role for T cells. The analysis of the T cell receptor (TCR) repertoire of I-cell subpopulations in tumor infiltrating cells gives information on the spectrum of recognized antigens. It reveals weather the T cell response is elicited by a few inimunodominant antigens or by a broad variety of tumor antigens. If a response to defined tumor antigens is mediated by T cells with a restricted set of TCRV genes or ICR clonotypes, it may be possible to monitor imniunotherapeutic effects or even to expand tumor specific T cells. In present study, we analyzed cytokines niRNA expression and ICR repertoire of T-cell subpopulations in tumor infiltrating cells in gastric cancer by a highly sensitive semi-quantitative RT-PCR technique. Purified CD~, CD~7 I cells and epithelial cells were obtained from single cells suspension from tumor tissue and autologous benign mucosal tissue with immunobeads, then total RNA was extracted and eDNA was prepared by reverse transcription for PCR reaction. Part 1. AnalysIs of cytoklnes expression In gastric cancer With J3-actin as an internal control, we detected the levels of both Thu Th2 type cytokines as well as TNF-cx, TGF]31 in isolated CD~ +and CD~ subsets of TILs and. autologous peripheral blood lymphocytes (PBL) with normal mucosal lymphocytes (ML) as lymphocyte controls, as well as in purified tumor epithelial 7 cells with residual benign gastric epithelial cells as controls, by semi-quantitative RT-PCR technique with specific primers for cytokines, Our data demonstrated: 1. A shift of Thl/Th2 balance to Th2梐 predominance of increased Th2 (IL-4, IL-6, IL-8, IL-b) and reduced Thl(IL-2, IFN-y) immune response in the TIL, compa...