IDO1 and infection: Notably, the specific downregulation of the Ido1 gene in GC cells post-infection, which encodes indoleamine 2,3-dioxygenase involved in tryptophan catabolism and immune regulation (Seo and Kwon, 2023), ranked among the top three significantly downregulated genes in both the De_Chlamydia and Chlamydia groups (Figure 3G; Supplementary Figure S2), pinpointing it as a potent target following Chlamydia infection in GC cells.