Mucin and Toll-like receptors in host defense against intestinal parasites.

Gastrointestinal mucin is a constituent of luminal barrier function and is the first line of host defense against invading pathogens. Mucin carbohydrates and amino acids, as well as trapped soluble host defense molecules, serve as substrates for colonization and control or deter pathogen invasion to the underlying mucosal epithelial cells. Toll-like receptors on the surface of epithelial cells act as sensors for invading pathogens, and the ensuing host response limits parasite invasion and leads to adaptive immunity. The latest work in the field and the use of parasite model systems to illustrate the delicate host-parasite interaction at the mucosal surface of the gut are discussed here.