In this study, we aimed to investigate whether P. gingivalis mediates Th1 cell differentiation to exacerbate EAE pathology and to explore the underlying mechanism.

T cells isolated from the splenic lymphocytes of mice in the EAE, and EAE+P groups (n = 4) were collected at 17 dpi.To investigate the mechanism by which periodontitis promotes Th1 differentiation in splenic lymphocytes of EAE mice, we performed RNA sequencing on T cells in splenic lymphocytes from both the EAE and EAE+P groups. A total of 5335 genes exhibited significant differential expression between the two groups, including 2297 upregulated and 3038 downregulated genes. Compared to the EAE group, the EAE+P group demonstrated a significant upregulation of Th1 differentiation- and inflammation-related genes, particularly IFNG and TGFB. Notably, Th1 differentiation-related genes, such as TRAC, CD3E, CD4, ZAP70, NFKB1, NFKB2, and IL-12b, were significantly upregulated in the EAE+P group