Meanwhile, the PD-L1 mRNA expression was significantly increased in PBM from the BVDV-infected mice than in PBM from the mock-infected mice at day 7 of post-infection (CP BVDV, p < 0.001, Figure 4B; NCP BVDV, p < 0.01, Figure 4B). Here, CD274 is linked to infection.