We observed that while 98% of WT microglia expressed MHC II at 12 days post-infection (DPI), 18% of microglia from MGSTAT1Δ mice were MHC II+ at this time point, allowing us to use MHC II expression in microglia as a reliable readout for STAT1 excision across experiments (Figs 2B, S1E and S1F). The gene discussed is STAT1; the disease is infection.