Portal of Entry and Haven of Refuge: Mucosal Responses to Infection in the Small Intestine

摘要

Over 90% of pathogens invade through mucosal surfaces and many of these pathogens use the intestine as a portal of entry. A variety of innate immune defense mechanisms have evolved to prevent pathogen attachment and invasion but viruses and bacteria have also developed strategies to evade these host defenses. In particular, it appears that the terminal region of the small intestine may be especially vulnerable to pathogen invasion in young ruminants. Our group has been studying the development of themucosal immune system in ruminants. We have identified a number of unique features which characterize the development and function of mucosa-associated lymphoid tissue (MALT) in the ileum of sheep and cattle. This presentation will review the development of MALT in ruminants and the use of experimental models to analyze the induction of both adaptive and innate mucosal immune responses. Regional differences in mucosal immune responses will be highlighted and the implications of these differences will be discussed in terms of host-pathogen interactions.