Irf1–/– mice were obtained from Jackson Laboratory (Bar Harbor, ME), Sphk1–/– mice were provided by Dr. Richard Proia, National Institutes of Health (Bethesda, MD), and Stat1–/– mice were provided by Dr. Andrew Larner, VCU (Richmond, VA). Irf3–/–Irf7–/– double-knockout mice46 (link) were generated and housed at WUSM, while all other mice were housed at VCU according to guidelines of VCU Institutional Animal Care and Use Committee and mouse protocols were approved by the institutional IACUC. 8-16 week old male and female mice were used.