title: Human intestinal M cells exhibit enterocyte-like intermediate filaments.
abstract: BACKGROUND
  The derivation and ultrastructural composition of M cells covering the lymphoid follicles of Peyer's patches is still unknown. Results from different animal models have shown that there are species specific differences in the composition of intermediate filaments between M cells and neighbouring enterocytes. Little is known, however, about intermediate filaments of human M cells.
  
  
  OBJECTIVE
  To compare components of the cytoskeleton of human M cells with those of adjacent absorptive enterocytes.
  
  
  METHODS
  The expression and localisation of different cytokeratins, vimentin, and desmin in M cells was determined on follicle associated epithelia of human appendix using immunohistochemistry and immunogold electron microscopy.
  
  
  RESULTS
  Cytokeratins specific for human intestinal epithelial cells such as cytokeratins 8, 18, 19, and 20 were expressed in both absorptive enterocytes and M cells with no differences in intensity and cellular distribution between both cell types. Vimentin and desmin, tissue specific markers of either mesenchymal or myogenic cells, as well as other cytokeratins were not detectable in enterocytes or M cells.
  
  
  CONCLUSIONS
  This is the first study on the structure of intermediate filaments in human intestinal M cells. Our results show that in contrast to several animal models, human M cells apparently do not differ from adjacent enterocytes in the composition of their intermediate filament cytoskeleton. The presence of enterocyte like cytokeratins and the absence of other cytokeratins as well as of vimentin and desmin supports the hypothesis of an epithelial origin of human intestinal M cells and suggests that M cells may derive from differentiated enterocytes.
authors.affiliation: Department of Medicine B, University of Münster, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Kucharzik
authors.forename: N
authors.initials: N
authors.lastname: Lügering
authors.forename: K W
authors.initials: KW
authors.lastname: Schmid
authors.forename: M A
authors.initials: MA
authors.lastname: Schmidt
authors.forename: R
authors.initials: R
authors.lastname: Stoll
authors.forename: W
authors.initials: W
authors.lastname: Domschke
mesh_terms: D000328:Adult; D000368:Aged; D001065:Appendix / Q000166:cytology* / Q000276:immunology; D004847:Epithelial Cells / Q000737:chemistry / Q000276:immunology / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007382:Intermediate Filaments / Q000737:chemistry / Q000648:ultrastructure*; D007633:Keratins / Q000032:analysis*; D008221:Lymphoid Tissue / Q000737:chemistry / Q000276:immunology / Q000648:ultrastructure*; D008297:Male; D016253:Microscopy, Immunoelectron; D008875:Middle Aged
chemical_list: D007633:Keratins