Figure 3

Flow cytometric analysis of bovine PD-L1 expression in BLV-infected cattle. A: Typical cases of different expression levels of PD-L1 in BLV-infected cattle at different disease stages determined by flow cytometric analysis. Bold lines indicate the up-regulation of the PD-L1 expression in the PL animal. B, C, D: Flow cytometric analysis of the PD-L1 expression on PBMC (B), CD5⁺ (C), and IgM⁺ (D) cells during the BLV-induced disease progression. PBMC from BLV-negative (BLV (-): n = 11 in B, 5 in C and D) and BLV-infected cattle with AL (n = 11 in B, 8 in C and D), PL (n = 19) and lymphoma (n = 9 in B, 8 in C, 5 in D) were analyzed. Individual dots indicate percentages of PD-L1⁺ cells in PBMC from BLV-uninfected (circle), AL (square), PL (upward triangle) and lymphoma (downward triangle). Each line indicates the mean percentages in each group. Statistical comparisons were made using the one-way ANOVA with Tukey's post test. Differences between groups were considered statistically significant at probability values of P < 0.05 (* P < 0.05; ** P < 0.01; *** P < 0.001).