To explore whether PD-1 plays a role in maintenance of lymphoid TRM cells, we examined the distribution of antiviral CTLs in the MLNs of IAV infected mice during treatment with antibodies that block interactions with PD-1 ligand (PD-L1) (36).To visualize antiviral CTLs in the MLN, naïve (CD11alowCD44low) OTI cells were transferred to B6 mice 48 h before infection with WSN-OVAI. After 30 days, the recipient mice were treated twice with antibodies that block interactions with PD-L1, or an isotype control. Here, CD274 is linked to infection.