Infection of PBECs with hMPV at a MOI of 0.1 induced the expression of PD-L1 and PD-L2 at 48 h and 72 h post-infection, and UV-irradiated hMPV did not increase PD-L1 or PD-L2 expression (Figure 8A, S6). Here, PDCD1LG2 is linked to infection.