Fig. 4

SMC18 effectively inhibits the phosphorylation of PD-1 and restores T cell function. A Representative Western blotting of PD-L1 phosphorylation in the co-culture system of Jurkat (stimulated with PMA and PHA) with CHO-K1-hPD-L1 cells treated with PBS, SMC18 (50 μM), and anti-hPD-1 antibody. IP (immunoprecipitation), IB (immunoblotting), and anti-pY (anti-phosphotyrosine). n = 3. B Representative flow cytometry and the pooled data of IL-2 secretion in co-culture experiments of Jurkat (stimulated with PMA and PHA) with CHO-K1-hPD-L1 cells. C Representative flow cytometry and the pooled data of IL-2 secretion in co-culture experiments of Jurkat (stimulated with anti-hCD3 and anti-hCD28) with CHO-K1-hPD-L1 cells. The data are presented as means ± S.E.M. Statistical significance was determined using the unpaired Student's t-test (*P < 0.05, **P < 0.01, ***P < 0.001)