Probiotics: A Clinical Guide

Martin H. Floch, MD; Adam S. Kim, MD

Chapter 2: Intraluminal Defenses (continued)

Ailsa Hart, PhD; Siew C. Ng, PhD

The human gastrointestinal (GI) tract represents the largest surface area of the body that is colonized by a diverse and dynamic microbial community. It is constantly exposed to large numbers of bacteria, including the resident microbiota as well as foreign bacteria. The mucosal immune system is poised to sense the local environment and needs to avoid potentially harmful responses to dietary antigens and the resident microbiota while responding rapidly to challenges from pathogens. There is a constant level of highly regulated physiological inflammation in operation involving a network of…