CCL2 and periodontitis: The results showed that periodontitis-related salivary microbiota treatment significantly changed the overall landscape of immune response-related gene expression in the intestine, with conspicuous upregulation of differentially expressed genes (DEGs), such as TNF-α, IL-1β, CCL2, CCL5, CXCL2, and CCL7 in the colon tissue (Figure 4b).