CD34 immunoreactivity and interstitial cells of Cajal in the human and mouse gastrointestinal tract.
Immunoreactivity for the tyrosine kinase receptor Kit (Kit-ir) is an established marker for the interstitial cells of Cajal (ICC) of the gut. Recently, the presence of CD34 immunoreactivity (CD34-ir) has been reported in Kit-ir ICC around the myenteric plexus in human small intestine. Conversely, we observed that CD34-ir labeled Kit-negative fibroblast-like cells, closely adjacent to, but distinct from, the Kit-ir ICC. The existence of cells expressing both CD34-ir and Kit-ir remains controversial. CD34-ir and Kit-ir were studied by high-resolution confocal microscopy on cryostat sections of human and murine gut as well as murine whole-mounts, using specific antibodies raised to human and murine CD34, respectively. CD34-ir labeled numerous cells in all parts of the gut, in man and in mouse. CD34-ir was consistently observed in Kit-negative cells, distinct from the closely adjacent Kit-ir ICC. Thin processes of both cell types intermingled extensively, often at the limit of resolution for light microscopy. CD34-ir was also observed in Kit-negative mesenchymal cells in the submucosa, in capillaries and in mesothelial cells. CD34-ir is not a marker for Kit-ir ICC in the human and murine gut. No CD34-ir, Kit-ir-expressing cells were encountered. Conversely, CD34-ir cells, closely adjacent to, but distinct from, Kit-ir ICC were consistently identified. The intimate relationship between these cells may offer an alternative explanation for reports of CD34 and Kit co-localization. The ontogeny and function of CD34-ir cells in the gut, as well as the origin of gastrointestinal stromal tumors, remain unclear.
Vanderwinden
J M
JM
Laboratoire de Neurophysiologie, Faculté de Médecine, Université Libre de Bruxelles, Campus Erasme, Brussels, Belgium. jmvdwin@ulb.ac.be
Rumessen
J J
JJ
De Laet
M H
MH
Vanderhaeghen
J J
JJ
Schiffmann
S N
SN
D000818:Animals; D018952:Antigens, CD34 / Q000276:immunology / Q000378:metabolism*; D003106:Colon / Q000033:anatomy & histology / Q000166:cytology* / Q000378:metabolism; D017615:Enteric Nervous System / Q000166:cytology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D007421:Intestine, Small / Q000166:cytology* / Q000294:innervation / Q000378:metabolism; D051379:Mice; D009130:Muscle, Smooth / Q000166:cytology / Q000294:innervation / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000276:immunology / Q000378:metabolism*; D013270:Stomach / Q000033:anatomy & histology / Q000166:cytology*
D018952:Antigens, CD34; D019009:Proto-Oncogene Proteins c-kit