Characterization of M cell formation and associated mononuclear cells during indomethacin-induced intestinal inflammation.
M cells represent an important gateway for the intestinal immune system by delivering luminal antigens through the follicle-associated epithelium to the underlying immune cells. The goal of this study was to characterize this route of antigen uptake during intestinal inflammation by characterizing M cell formation and M cell-associated lymphocytes after indomethacin challenge in rats. We demonstrated increased M cell formation as early as 12 h after a single injection of indomethacin. The elevated M cell counts were determined until day 3 and returned to basal levels after 7 days. Electron microscopic studies revealed an expansion of mononuclear cells inside the M cell pocket that were characterized predominantly as B cells, T cell receptor (TCR)alphabeta- and CD4-positive T cells, whereas other markers such as CD11b, CD8 and CD25 remained unchanged. In situ hybridization studies showed increased expression of interleukin (IL)-4 by lymphocytes during intestinal inflammation in the Peyer's patch follicle. These studies illuminate the relevance of M cells during intestinal inflammation and suggest that M cells derive from epithelial cells in a certain microenvironment.
Lügering
A
A
Department of Medicine B, University of Münster, Münster, Germany. lugerin@uni-muenster.de
Floer
M
M
Lügering
N
N
Cichon
C
C
Schmidt
M A
MA
Domschke
W
W
Kucharzik
T
T
D000818:Animals; D005260:Female; D007079:Ileitis / Q000276:immunology*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D007213:Indomethacin; D015847:Interleukin-4 / Q000235:genetics / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D016253:Microscopy, Immunoelectron; D023421:Models, Animal; D010581:Peyer's Patches / Q000166:cytology* / Q000276:immunology / Q000648:ultrastructure; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar
D012333:RNA, Messenger; D015847:Interleukin-4; D007213:Indomethacin