The Novel Crohn's Disease Marker Anti-GP2 Antibody Is Associated with Ileocolonic Location of Disease

Figure 2

Glycoprotein 2 ((GP2) green) is synthesized by acinar pancreatic cells and released together with digestive enzymes into the intestinal lumen. Provided that GP2 is not digested by activated enzymes, GP2 can opsonise FimH positive microbes (FimH +) in the intestine. Additionally, GP2 has been demonstrated on the surface of microfold cells (M cells) of the Peyer’s patches (PP) of the follicle-associated epithelium. This form of GP2 can interact with FimH positive bacteria and partake in the transcytosis thereof by the M cells. After the loss of tolerance towards GP2, plasma cells can synthesize anti-GP2 IgA which will be actively transported by the epithelium into the lumen of the intestine. The secreted anti-GP2 IgA can bridge FimH positive bacteria opsonised by pancreatic GP2 with the membrane-bound GP2 on the M cells (highlighted). Ultimately, this could lead to an overload of microbes in the mucosa due to an elevated transcytosis rate accelerating intestinal inflammation [13].