A healthy intestinal mucosa is one in which induced adaptive immune responses to pathogenic infections are balanced by the lack of responses to innocuous food antigens and commensal microbes. This balance is maintained by an array of different subsets of effector T cells and regulatory T cells that reside in the intestinal epithelium and lamina propria. Although these different T cell subsets have diverse patterns of cytokine production and other effector functions, they share:
A) The ability to live for months to years in the intestinal epithelium
B) The ability to secrete immunosuppressive cytokines
C) The ability to inactivate dendritic cells that have received signals through pattern recognition receptors
D) The expression of gut-homing chemokine receptor, CCR9
E) The ability to bind to E-cadherin on the intestinal epithelial cells

Question

Quizplus · Accepted Answer

All subsets of T cells residing in the intestinal epithelium and lamina propria express the gut-homing chemokine receptor, CCR9, which enables them to migrate to and remain in the gut.

Answer: B
 Regulatory T cells (Tregs) residing in the intestinal mucosa secrete immunosuppressive cytokines, such as IL-10 and TGF-beta, which help to maintain immune tolerance to harmless food antigens and commensal microbes.

Therefore, the correct choices are D and B.

A Healthy Intestinal Mucosa Is One in Which Induced Adaptive