CD274 and infection: Both IL-10 and PD-L1 are well known inhibitors of CD8+ T function and, as shown by Shaabani and collaborators, upon infection with lymphocytic choriomeningitis virus (LCMV), type I IFNs are produced in high amounts by CD169+ macrophages to combat the virus, but as a consequence leads to up-regulation of PD-L1 and therefore CD8+ T cell exhaustion [147].