IFNA1 and viral infectious disease: The intestinal microbiota also influenced the host interferon (IFN) response during persistent MNV infection in a manner promoting viral infection [28]: Whereas persistent MNV infection was reduced in antibiotic-treated wild-type mice and mice deficient in type I or type II IFN receptors, it was not affected by antibiotic treatment in mice lacking the type III IFN (IFN-λ) receptor; STAT-1 (a key IFN signaling molecule); or IRF3 (a transcription factor required for IFN gene expression).