Fig. 4: PD-1 marks highly activated liver CD8⁺ Trm cells in PBC.

a Volcano plot shows the differentially expressed genes between CD8⁺ Trm and non-Trm cells in DKO liver. b Dot plot shows PD-1 expression of DKO liver CD8⁺ T cell subsets. The color of dots represents the average expression of genes and size for the percent of cells expressed the genes. c Representative flow plots of CXCR6 and PD-1 expression on DKO liver CD8⁺ Tcm, Tem and Trm cell subsets. d Representative multi-colored immunohistochemistry graph of CXCR6^GFP DKO liver stained with DAPI (blue), GFP (green), CD8 (red) and PD-1 (yellow). e Representative multi-colored immunohistochemistry graph of DKO liver stained with DAPI (blue), CK19 (pink), CD8 (green) and PD-1 (red). The white arrows pointed to PD-1⁺CD8⁺ T cells. f Statistics of the distance between PD-1^+/−CD8⁺ T cells and the nearest CK19⁺ bile duct epithelial cells in DKO liver (n = 3). Data in (d, e) are representative results of at least two independent experiments. Box-and-whisker plots show the median (center line), 25th, and 75th percentile (lower and upper boundary), whiskers extend to the farthest data points. The p values were determined by Wilcoxon test, Bonferroni p value correction (a), a two-tailed unpaired t-test (f).