M cells and Mucosal Immune Surveillance

Mucosal surfaces in the lung and intestine are exposed to environmental antigens and allergens and, in the case of the intestine, abundant food antigens. They are also exposed to a variety of infectious organisms such as viruses (influenza, polio, SARS, HIV), bacteria (Staphylococcus, Streptococcus, Anthrax), and parasites (Toxoplasma). The mucosal immune system must be able to identify pathogenic infectious agents and respond to them without reacting to beneficial commensal bacteria, or developing allergic responses to food or environmental antigens.

At mucosal surfaces, epithelial cells provide a tight barrier to entry into the body, but the immune system also induces the development of specialized epithelial cells called M cells to detect the presence of infectious organisms. These M cells are selective gatekeepers that capture particles such as viruses and bacteria for delivery to cells of the immune system waiting below the epithelial layer. Our laboratory has been studying the development of M cells, and the mechanisms used by M cells in their selective uptake of particles. We are also using the information we have learned about M cell function to engineer a novel technology for needle-free vaccine delivery that we hope to use against influenza and other infectious organisms.