IFNG and bacterial infectious disease: iNKT cells have been shown to increase IFN-γ production in direct response to other bacterial infections, including S. pneumoniae, L. monocytogenes, and S. typhimurium (47, 51, 52), but this was the first study to our knowledge demonstrating that type II NKT cells upregulated IFN-γ production in direct response to SA infection in vivo.