Fig. 4

GDNPs improved arginine metabolism in TME to relieve T cell exhaustion. a Schematic illustration of GDNPs/Vehicle treatment regimen for MC38 colon tumor model. At 21 days, mice were sacrificed, and the anticancer effects in each group were evaluated and compared (n = 5). b Tumor volume at the end of the experiment were compared. c ARG1 expression in different immune cells in GDNPs/Vehicle groups (n = 5). d L-Arginine levels in GDNPs/Vehicle treatment of MC38 colon tumor were detected by L-Arginine Assay Kit. e The ratio of the proportion of M1-like to M2-like macrophages in the two groups was detected by flow cytometry. f, g Representative histograms and quantification of CD4 + and CD8 + T cell activation and proliferation in MC38 colon tumors treated with or without GDNPs. h, i Representative histograms and quantification of surface expression of ICOS, PD-1, TIGIT, and TIM3 on CD4 + and CD8 + T cells in MC38 colon tumors treated with or without GDNPs. j, k The expression of transcription factors Eomes, Tox and T-bet in CD4 + and CD8 + T cells were analyzed in MC38 colon tumors treated with or without GDNPs. All results represent the mean ± SEM (n = 5). Two-way ANOVA (b, c) and Student’s t test (d, e, f, g, h, j, k) were used to compare results of different experimental groups for statistically significant difference (*P < 0.05,**P < 0.01,***P < 0.001,****P < 0.0001)