The researchers of Riken and Yokohama City University have reported that a key mechanism involved in immune surveillance in the intestinal system. Their research is expected to appear in Nature on 12 November and could provide new targets for oral vaccines for infectious diseases and allergies.
The researchers said that the mucosal immune forms the largest part of the entire immune system and protects the body from pathogens and foreign particles by secreting the antibody Immunoglobin A (IgA). Specialised cells called microfold cells (M cells) capture and deliver foreign particles through the epithelial layer to lymphoid structures deeper in the intestinal tissue. This triggers the secretion of the antibodies.
The team show that the protein, glycoprotein 2 (GP2), on the outer membrane of M cells, acts as a receptor for certain pathogenic bacteria, rapidly instigating immune responses. Experiments demonstrate that in mice, GP2 specifically binds to bacteria such as E. coli and Salmonella by recognising a component of hairlike structures on the bacterial cell surface.
As a target for the development of new oral vaccines, GP2 also offers the hope of an easy-to-administer, cost-effective solution for infectious diseases and allergies.