| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Pediatrics, Harvard Medical School, GI Cell Biology Laboratory, Children’s Hospital Boston and Harvard Digestive Diseases Center, Boston, MA 02115
Initiation of adaptive mucosal immunity occurs in organized mucosal lymphoid tissues such as Peyer’s patches of the small intestine. Mucosal lymphoid follicles are covered by a specialized follicle-associated epithelium (FAE) that contains M cells, which mediate uptake and transepithelial transport of luminal Ags. FAE cells also produce chemokines that attract Ag-presenting dendritic cells (DCs). TLRs link innate and adaptive immunity, but their possible role in regulating FAE functions is unknown. We show that TLR2 is expressed in both FAE and villus epithelium, but TLR2 activation by peptidoglycan or Pam3Cys injected into the intestinal lumen of mice resulted in receptor redistribution in the FAE only. TLR2 activation enhanced transepithelial transport of microparticles by M cells in a dose-dependent manner. Furthermore, TLR2 activation induced the matrix metalloproteinase-dependent migration of subepithelial DCs into the FAE, but not into villus epithelium of wild-type and TLR4-deficient mice. These responses were not observed in TLR2-deficient mice. Thus, the FAE of Peyer’s patches responds to TLR2 ligands in a manner that is distinct from the villus epithelium. Intraluminal LPS, a TLR4 ligand, also enhanced microparticle uptake by the FAE and induced DC migration into the FAE, suggesting that other TLRs may modulate FAE functions. We conclude that TLR-mediated signals regulate the gatekeeping functions of the FAE to promote Ag capture by DCs in organized mucosal lymphoid tissues.
This article has been cited by other articles:
|
|
 |
|
  R. S. Munford Sensing Gram-Negative Bacterial Lipopolysaccharides: a Human Disease Determinant? Infect. Immun., February 1, 2008; 76(2): 454 - 465. [Full Text] [PDF]
|
|
|
|
 |
|
 J. Chen, J. N. Rao, T. Zou, L. Liu, B. S. Marasa, L. Xiao, X. Zeng, D. J. Turner, and J.-Y. Wang Polyamines are required for expression of Toll-like receptor 2 modulating intestinal epithelial barrier integrity Am J Physiol Gastrointest Liver Physiol, September 1, 2007; 293(3): G568 - G576. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Shaykhiev and R. Bals Interactions between epithelial cells and leukocytes in immunity and tissue homeostasis J. Leukoc. Biol., July 1, 2007; 82(1): 1 - 15. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. A. Shigeoka, T. D. Holscher, A. J. King, F. W. Hall, W. B. Kiosses, P. S. Tobias, N. Mackman, and D. B. McKay TLR2 Is Constitutively Expressed within the Kidney and Participates in Ischemic Renal Injury through Both MyD88-Dependent and -Independent Pathways J. Immunol., May 15, 2007; 178(10): 6252 - 6258. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. K. Petris, M. Golomb, and T. E. Phillips Bacterial Transcytosis across Conjunctival M Cells Invest. Ophthalmol. Vis. Sci., May 1, 2007; 48(5): 2172 - 2177. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Chieppa, M. Rescigno, A. Y.C. Huang, and R. N. Germain Dynamic imaging of dendritic cell extension into the small bowel lumen in response to epithelial cell TLR engagement J. Exp. Med., December 25, 2006; 203(13): 2841 - 2852. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
