The Immune Regulatory Effect Of PD-L1~+ Hela On Active Human Peripheral Blood T Lymphocytes

Objective: To study the immune regulatory effect of PD-L1~+Hela cells on active human peripheral blood T lymphocytes in vitro.Methods: PEGFP-N1-CD274-GFP plasmid which carrying PD-L1 gene were transfected into Hela cells, then PD-L1~+Hela cells were co-cultured with peripheral T lymphocytes which stimulated by PHA. The proliferative rate of T lymphocytes was determined by MTT; the apoptotic rate of T lymphocytes and the rate CD8~+T/CD4~+T were analyzed by flow cytometry; IFN-γconcentration in the supernatant of co-cultured T cells was measured by ELISA.Results: Compare to T cells which co-culture with PD-L1-Hela cells or T cells only, the OD value of proliferative T cells which co-cultured with PD-L1~+Hela cells was lower, they were 0.31±0.02, 0.62±0.02 and 0.59±0.03 (P﹤0.01); the apoptotic rates of T cells which co-cultured with PD-L1~+Hela cells was higher, they were 32.7%, 16.4% and 17.9%; The CD8~+T/CD4~+T rates were 0.86, 0.91 and 0.90; IFN-γconcentration in the supernatant of those groups were 801.1±20.5 pg/ml ,1006.2±30.2 pg/ml and 1070.2±113.3 pg/ml (P﹤0.01). Conclusion: PD-L1~+Hela cells significantly inhibits the proliferation of active human peripheral blood T lymphocytes, promotes their apoptosis and down regulates their immune response.