Antigen-sampling cells in the salmonid intestinal epithelium.
Antigen uptake has been shown to occur in the teleost intestine, but so far, limited information is available on the distribution and nature of cells involved in the process, and M cells, known for their antigen-sampling abilities in mammals, have not been identified. Here, different intestinal segments from salmonid fish were exposed to gold-BSA to identify antigen-sampling cells. Sections from exposed intestine were examined by light and electron microscopy. Uptake of gold-BSA was restricted to very few dendritic-like cells and to a limited number of epithelial cells located in the mucosal folds in the second segment of the mid-intestine. Gold-positive epithelial cells displayed diverging and electron-dense microvilli with channels intruding into the cytoplasm. A lectin binding experiment demonstrated the presence of cells with mammalian M-cell characteristics in the identical regions. As the identified epithelial cells shared some morphological similarities with immature mammalian M cells, this phenotype may represent evolutionary early antigen-sampling enterocytes.
Fuglem
Bjørn
B
Section of Anatomy and Pathology, Institute of Basic Sciences and Aquatic Medicine, Norwegian School of Veterinary Science, Ullevålsveien 72, Oslo, Norway.
Jirillo
Emilio
E
Bjerkås
Inge
I
Kiyono
Hiroshi
H
Nochi
Tomonori
T
Yuki
Yoshikazu
Y
Raida
Martin
M
Fischer
Uwe
U
Koppang
Erling Olaf
EO
D056704:Adaptive Immunity / Q000276:immunology; D000818:Animals; D000941:Antigens / Q000276:immunology*; D020895:Enterocytes / Q000166:cytology / Q000276:immunology* / Q000648:ultrastructure; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology* / Q000648:ultrastructure; D037102:Lectins / Q000276:immunology; D018613:Microscopy, Confocal / Q000662:veterinary; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D012487:Salmonidae / Q000276:immunology*
D000941:Antigens; D037102:Lectins