CGAS and infection: To test whether the nucleic acid-sensing pathways have a function in host defense against VACV∆C7L infection, we performed intranasal infection of VACV∆C7L in cGas−/−, Sting1gt/gt (which lack functional STING), Ifih1−/− (MDA5 knockout), Ifih1−/−Sting1gt/gt or Irf3−/− mice.