Conditional deletion of RANK in intestinal epithelial cells of mice results in loss of Peyer’s patch M cells and impaired acquisition of orally delivered antigen (49.2)

Abstract

Abstract Microfold (M) cells are antigen-sampling intestinal epithelial cells found in the follicle-associated epithelium (FAE) of Peyer’s patches (PPs). M cells initiate mucosal immune responses by transcytosis of particulate antigens for delivery to antigen-presenting cells that traffic through the intraepithelial pocket of M cells. We previously showed that RANKL from stromal cells in the subepithelial dome of PPs is necessary and sufficient for inducing M cell differentiation. To determine how selective loss of intestinal M cells affects host immune responses to antigens encountered in the gut lumen, we generated mice with a floxed allele of RANK deleted only in intestinal epithelial cells (IEC) by a villin-cre transgene (RANKΔIEC mice). The FAE of PP in RANKΔIEC mice lacked any cells expressing the M-cell marker GP2, proving that RANKL promotes M cell differentiation from intestinal stem cells via a direct action on RANK-expressing IEC. An OT-II T cell adoptive transfer model was used to analyze ovalbumin (OVA)-specific T cell responses 2 to 3 days after gavage with various forms of OVA. RANKΔIEC mice had compromised T cell responses to both soluble OVA and particulate OVA (OVA encapsulated in acid-stable microparticles prepared by spray drying). The RANKΔIEC mouse provides a first-of-its-kind mouse model for the specific assessment of the contribution of intestinal M cells to uptake of protein antigens and pathogenic microorganisms encountered in the intestinal lumen.