IFNG and infection: The roles of each IL-12 subunit were directly demonstrated using the respective KO mice: IL-12p40 KO mice never clear even a low dose intradermal (i.d.)or intranasal (i.n.)LVS infection, while IL-12p35 KO mice display only a slight delay in bacterial clearance, despite low IFN-γ levels in both KO animals [22, 23].