Scope
The mechanism through which peptide‐based immunotherapy provides effective desensitization toward food allergy is investigated.
Methods and results
Ex vivo experiments are conducted with intestinal epithelial cells (IECs), dendritic cells (DCs), and T cells from mice sensitized to egg white (EW) and either left untreated or tolerized by the oral administration of a hydrolysate of ovalbumin with pepsin (OP). IECs from EW‐sensitized mice upregulate Il33 and Tslp to a higher extent than those from tolerized mice and induce bone marrow (BM)‐DCs to express Tnfsf4 and produce pro‐inflammatory cytokines. On the other hand, incubation with OP upregulates Aldh1a1 in IEC cultures and BM‐DCs conditioned with supernatants of OP‐pulsed IECs also overexpress Aldh1a2 and Tgfb1. DCs from tolerized mice, in co‐culture with CD4+ T cells from sensitized mice, reduce the secretion of IL‐5, IFN‐γ, and IL‐17, following stimulation with EW, to a level similar than DCs from sham‐sensitized mice. Furthermore, incubation with OP of DCs and CD4+ T cells, regardless of the mouse sentitization status, promotes the secretion of TGF‐β and the generation of Foxp3+ RORγt+ cells.
Conclusion
OP induces the expression of aldehyde dehydrogenase enzymes in cells of the innate immune system and the development of Foxp3+ RORγt+ T cells.