Human endomucin: distribution pattern, expression on high endothelial venules, and decoration with the MECA-79 epitope.
Endomucin is a typical sialomucin that we recently identified on the surface of mouse endothelial cells and on putative hematopoetic clusters of the dorsal aorta in the embryo. We have generated a panel of monoclonal antibodies (mAbs) against the extracellular part of human endomucin and polyclonal antibodies against the cytoplasmic part. Using immunohistochemistry endomucin was specifically detected on endothelial cells of blood and lymphatic vessels of all analyzed human tissues. In addition, the polyclonal antibodies stained the epithelium of the epidermis as well as epithelial and myoepithelial cells of the eccrine and apocrine glands in the skin. This nonendothelial staining could only be seen with a subset of mAbs if the staining procedure was amplified. Although high endothelial venules (HEVs) were not significantly stained with mAbs against endomucin, the polyclonal antibodies clearly detected endomucin on HEVs in lymphatic organs of the mouse and human, suggesting HEV-specific glycosylation affecting recognition by the mAbs. Indeed, endomucin isolated from human and mouse lymphoid organs carried the MECA-79 epitope that defines a set of L-selectin ligands on HEVs called peripheral node addressins. We conclude that human and mouse endomucin are endothelial sialomucins with the potential to function as L-selectin ligands.
Samulowitz
Ulrike
U
Institute of Cell Biology, ZMBE, University of Münster, Germany.
Kuhn
Annegret
A
Brachtendorf
Gertrud
G
Nawroth
Roman
R
Braun
Attila
A
Bankfalvi
Agnes
A
Böcker
Werner
W
Vestweber
Dietmar
D
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D001483:Base Sequence; D002460:Cell Line; D004730:Endothelium, Vascular / Q000378:metabolism; D000939:Epitopes / Q000276:immunology; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D007962:Leukocytes / Q000737:chemistry; D008208:Lymphatic System / Q000737:chemistry; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D009000:Monocytes / Q000737:chemistry; D009077:Mucins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D052116:Sialomucins
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D000939:Epitopes; C069886:L-selectin counter-receptors; D008565:Membrane Proteins; D009077:Mucins; D052116:Sialomucins