IFNG and bacterial infectious disease: Bacterial DNA containing unmethylated cytosine-guanidine motifs linked by a phosphodiester (p) group (CpG) activates mammalian lymphocytes and macrophages to produce cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-12, and interferon gamma (IFN-γ), which are crucial for the immune response to bacterial infections [8].