Fig. 2

Expression levels of PD-1, PD-L1 and CD3⁺ T cell infiltration in PD-1R, PD-1S and control IgG groups. Representative immunohistochemically stained images of the tissue sections from the tongue. PD-1 (a) and PD-L1 (b) staining was detected in three groups. The expression of PD-1 and PD-L1 in the PD-1S and PD-1R groups were both lower than that in the control group, and the expression of PD-L1 in PD-1S group is significantly lower than PD-1R group(P < 0.05). c CD3⁺ T cell infiltration increased in the PD-1S group but decreased in the PD-1R group compared with the control group(P < 0.05). The boxes outlined with solid lines are the representative sites in the 100× or 200× pictures. The 400× images show high-magnification views of the boxed areas