Antigen Sampling Across Epithelial Barriers and Induction of Mucosal Immune Responses

Abstract

Epithelial barriers on mucosal surfaces at different sites in the body differ dramatically in their cellular organization, and antigen sampling strategies at diverse mucosal sites are adapted accordingly. In stratified and pseudostratified epithelia, dendritic cells migrate to the outer limit of the epithelium, where they sample antigens for subsequent presentation in local or distant organized lymphoid tissues. In simple epithelia, specialized epithelial M cells (a phenotype that occurs only in the epithelium over organized lymphoid follicles) deliver samples of foreign material by transepithelial transport from the lumen to organized lymphoid tissues within the mucosa. Certain pathogens exploit the M cell transport process to cross the epithelial barrier and invade the mucosa. Here we review the features of M cells that determine antigen and pathogen adherence and transport into mucosal lymphoid tissues.

Intestinal and Splenic T Cell Responses to EntericListeria monocytogenesInfection: Distinct Repertoires of Responding CD8 T Lymphocytes

“…The intestinal mucosa provides an extensive and intimate interface with the microbial world that is perpetually confronted with potentially invasive pathogens (35). Although it is assumed that intestinal T lymphocytes, in particular IEL, protect the host from microbial invasion (36), the specificity of intestinal T cells after bacterial infection has not been previously determined.…”

CTA1-DD-Immune Stimulating Complexes: a Novel, Rationally Designed Combined Mucosal Vaccine Adjuvant Effective with Nanogram Doses of Antigen

“…Alternatively, the vectors may enter across the villus epithelium before being transported to B cells in the mesenteric lymph node via the draining lymph. Although both routes have been implicated in the intestinal immunogenicity of intact CT (11), CTA1-DD lacks the GM1-ganglioside binding activity that may assist the uptake of CT holotoxin by enterocytes (28). Thus CTA1-DD in ISCOMS may enter the immune system of the gut-associated lymphoid tissues by a distinctive mechanism.…”

Gastrointestinal lesions associated with spondyloarthropathies

“…The epithelial lining of the gastrointestinal tract includes specialized cells (M cells) which per mit transepithelial transport of foreign material from the lumen to mucosal lymphoid tissues; it is evident that some microorganisms use the M cell transport system as a means to infect the mucosa [10,15] . The human intestine harbours a complex microflora composed of aerobic and anaerobic bacteria.…”