Despite impairments in liver IFN-a production in 3d mice, it is notable that this response was not totally abrogated. This suggests the presence of alternative pathways to type I IFN production in the liver, and may be the reason that IFNa/bR-deficient mice die by day 5 in response to infection with a moderate dose of MCMV, as reported previously [36] , while 3d mice do not. Studies have also demonstrated production of type I interferon from cells other than pDCs at 44-48 hours following MCMV infection [32, 48, 49] . In addition, the liver contains a variety of parenchymal and nonparenchymal cells that express TLRs and are capable of type I IFN production [38, [40] [41] [42] . There may also be TLR-independent pathways leading to the production of these cytokines in response to MCMV, including cytoplasmic RNA-and DNA-sensing receptors, as have been demonstrated with other virus models but have yet to be examined in the context of MCMV infection [1] [2] [3] [4] [50] [51] [52] [53] [54] [55] .