The Impact Of Tolerogenic Dendritic Cell Induced By VEGF On T Lymphocyte Immune Function In Oral Cancer

[Objective] To study the impact of tolerogenic dendritic cell induced by VEGF on T lymphocyte immune function in oral cancer.[Method] 1. The level of VEGF in the above serum of SCC7 cultured in vitro was tested by ELISA (enzyme-linked immunosorbent assay). The bone marrow precursor cells from C57BL/6 mice was cultured with GM-CSF and IL-4. In vitro the bone marrow precursor cells were induced by oral squamous cell carcinoma cell line(SCC7) in transwell. Methods to set up control group, VEGF group, SCC7 conculture group and VEGF antagonism group. The morphology of DCs were observed by optical microscope. On day 5 of culture, DCs were harvested and then analyzed by flow cytometry (FCM) for their phenotypes, mixed lymphocyte reaction(MLR) for allostimulatory function, ELISA for the level of IL-12 secreted by DC.2. The expression of IDO, PD-L1 on imDC were detected by FCM and real-time quantitative PCR. The ability of T lymphocyte proliferation induced by imDC expressed IDO, PD-L1 were detected by MLR. Experimental data were analyzed by SPSS18.0.[Results] 1. The levels of VEGF in the culture supernatant of SCC7 were increased along with the prolongation of the culture time. It is up to 630pg/ml in 72 hours culture medium. On day 5, the cells displayed typical morphology with DC process and the expression of specific markers of bone marrow derived DC-CD11c and costimulation molecules of CD80、 CD86、CD40 and MHCII on controls were 60.47±6.13%、54.67±0.91%、45.3±0.92%、 65.47±1.14% and 30.8±1.57%, higher than other groups. The specific markers in SCC7 conculture group were lower than VEGF antagonism group. The level of IL-12 secreted by imDC in VEGF group, conculture group and VEGF antagonism group were lower than control group. Each group of imDC can stimulate the T lymphocyts proliferation mildly and with the increase of DC/T cell culture, the ability of T cell proliferation enhanced. The stimulatory capacity of DC to T cell proliferation in VEGF group, conculture group and VEGF antagonism group were weaker than control. In VEGF antagonism group the ability was stronger than conculture group.2. IDO, PD-L1 in imDCs were stimulated by VEGF and oral cancer microenviroment. The expression rate of IDO and PD-L1 were 88.57±1.36% and 69.1±0.95% in conculture group,79.2±2.55% and 61.27±1.7% in VEGF antagonism group. IDO and PD-L1 expresssed in imDCs can influence the immune function of T lymphotecyte. Inhibiting the expression of IDO and/or PD-L1 by 1MT and MIH5 can promote T cell proliferation.[Conclusion] VEGF in tumor microenviroment of oral cancer can inhibit the differentiation of mice myeloid DC, matian their immature state and inhibit the ability of DC to stimulate T cell proliferation in vitro. VEGF from oral cancer can promote IDO, PD-L1 expression in imDC, and high expression of IDO and PD-L1 can inhibit the T cell immune function.