B7 Family Molecule VSIG4 Regulates Intestinal Anti-Enterohemorrhagic Escherichia coli Immunity by Altering Gut Flora Diversity

As an essential member of the B7 family, V-set and immunoglobulin domain-containing 4 (VSIG4) is expressed explicitly in tissue-resident macrophages (TRMs) and plays an essential role in maintaining the homeostasis of the environmental immune system. Here, we demonstrate that gene-targeted VSIG4-deficient mice infected with Enterohemorrhagic Escherichia coli (EHEC) display reduced bacterial burden. To reveal the role of VSIG4 in the fight against EHEC infection, we collected mice feces and used high-throughput 16S rRNA gene amplicons to detect changes in the flora. A total of 657330 sequences were sequenced on the PacBio platform, with an average length of 1498 bp. We found that VSIG4 deficiency could alter the gut microbiota by increasing diversity and shifting community composition. In particular, G_Akkermansia and G_Oscillo spiraceae increased significantly. These findings expand upon a prior observation that VSIG4 deficiency reduced EHEC colonization by changing the gut microbiota diversity and shifting community composition.