CGAS and infection: MNV can replicate in murine macrophages and dendritic cells, but not in epithelial cells or human cells because of a restriction at viral entry.31,38,39 Discovery of the cell-surface expressed MNV receptor (CD300lf) enables MNV infection in human cells (like HeLa and HEK293T cells) and facilitates identification of antiviral cellular factors.9,31,40 Overexpression of mouse cGAS and STING moderately upregulates ISG expression, but potently restricts MNV replication in HEK293T cells ectopically expressing viral receptor.