The Journal Of Allergy And Clinical Immunology
The etiology of food allergy is poorly understood; mouse models are powerful systems to discover immunologic pathways driving allergic disease. C3H/HeJ mice are a widely used model for the study of peanut allergy because, unlike C57BL/6 or BALB/c mice, they are highly susceptible to oral anaphylaxis; yet the immunologic mechanism of this strain’s susceptibility is not known. We aimed to determine the mechanism underlying the unique susceptibility to anaphylaxis in C3H/HeJ mice. We tested the role of deleterious toll-like receptor 4 (Tlr4) or dedicator of cytokinesis 8 (Dock8) mutations in this strain as both genes have been associated with food allergy. We generated C3H/HeJ mice with corrected Dock8 or Tlr4 alleles and sensitized and challenged with peanut. We then characterized the antibody response to sensitization, anaphylaxis response to both oral and systemic peanut challenge, gut microbiome and biomarkers of gut permeability. In contrast to C3H/HeJ mice, C57BL/6 mice were resistant to anaphylaxis following oral peanut challenge; however, both strains undergo anaphylaxis with intraperitoneal challenge. Restoring TLR4 or DOCK8 function in C3H/HeJ mice did not protect from anaphylaxis. Instead, we discovered enhanced gut permeability resulting in ingested allergens in the bloodstream in C3H/HeJ mice when compared with C57BL/6 mice, which correlated with increased number of goblet cells in the small intestine. Our work highlights the potential importance of gut permeability in driving anaphylaxis to ingested food allergens and that genetic loci outside of Tlr4 and Dock8 are responsible for the oral anaphylactic susceptibility of C3H/HeJ mice.