IFNA1 and infection: First, a greater type I IFN response was observed during AF2122 infection, with higher expression of IFN-α and IFN-β proteins, along with the downstream type I IFN response genes, e.g., MX1 and RSAD2. Type I IFNs are induced in response to stimulation of pathogen recognition receptors, many of which are cytosolic, e.g., NOD2, cGAS, and RIG-1 (43).