动物造模 z-bio 2023-02-28 1420

　　Objective To observe the dynamic changes of tumor-infiltrating immune cells during tumor development in tumor-bearing mice.

　　Methods Mouse colon cancer MC38 cells were subcutaneously transplanted into 24 C57BL/6J mice. After tumor-bearing, the changes in the body weight and tumor size of the mice were recorded once a week, and the level of tumor-infiltrating immune cells was detected by flow cytometry once a week. , including CD45+ cells, CD3+ T cells, CD8+ T cells, CD4+ T cells, natural killer (NK) cells, dendritic cells, macrophages, M1 macrophages, M2 macrophages, myeloid derived Suppressor cells (myeloid-derived suppressor cells, MDSC), monocytic-myeloid-derived suppressor cells (monocytic-MDSC, M-MDSC), granulocytic-derived suppressor cells (granulocytic-MDSC, M-MDSC) were detected for a total of 4 weeks.

　　Results With the growth of colon cancer tumors in mice, the level of CD45+ cells generally showed a downward trend, the level of CD8+ T cells steadily decreased to an irreversible level, and the proportion of CD4+ T cells increased rapidly in the early stage of tumor bearing, and the number of infiltrating cells per unit volume increased. Nearly 8-fold, tumor-infiltrating T cells were almost CD4+ phenotype. The level of non-specific immune responses represented by NK cells continued to decline, while dendritic cells continued to accumulate in the tumor, and stimulated through the activation of arginase-1 (Arginase-1, ARG1) and inducible nitric oxide synthase (inducible). nitric oxide synthetase, iNOS), further deepening the immunosuppressive effect. There was no significant change in the overall level of macrophage infiltration, but the decline rate of type I macrophage infiltration cells was significantly higher than that of type II. The number of MDSCs in the tumor per unit volume did not decrease

　　The infiltration level of G-MDSC showed a steady downward trend, and the infiltration level of M-MDSC continued to increase, and the proportion was much higher than that of G-MDSC.

　　Conclusion After transplantation of MC38 colon cancer cells in mice, the level of immune cell infiltration in the tumor tissue decreased as a whole, and the promotion of tumor immunity gradually dominated, thereby promoting the development of colon cancer. Th1/Th2 drift phenomenon occurred in the tumor, the levels of specific and non-specific immune responses were significantly reduced, and the infiltrating monocytes and granulocytes were mainly Ly6C+ phenotype. Tumor-associated dendritic cells and macrophages play an important role in immunosuppression, and CD4+ T cells and M-MDSCs may be the key points in exerting tumor-promoting immune effects.