Characterization of an apparently conserved epitope in E- and P-selectin identified by dual-specific monoclonal antibodies.
E- and P-selectin recognize a wide and overlapping range of oligosaccharide ligands including sialyl-Lewis X (sLeX) through their highly homologous C-type lectin domains. We report that an epitope apparently conserved between E- and P-selectin is functionally involved in ligand recognition although distantly located from the conventional carbohydrate binding site. We found that a previously established anti-E-selectin monoclonal antibody (mAb), 1.2B6, is cross-reactive with P-selectin, and that the 1.2B6 epitope is in the C-type lectin domain and identical to or overlapping with an epitope recognized by other independently established anti-E- and P-selectin dual-specific mAb. The epitope has been mapped by others to a region distant from the previously identified carbohydrate binding site of E-selectin in its three-dimensional structure. Nevertheless, it is of note that all dual-specific mAb, including 1.2B6, inhibited E- or P-selectin-mediated cell adhesion and also binding to sLeX. Engagement of the apparently conserved epitope by the dual-specific mAb may lead to inhibition of the ligand binding ability of E- and P-selectin by a previously uncharacterized mechanism(s) rather than by direct inhibition of sLeX binding to the hitherto identified ligand binding site.
Goda
K
K
Department of Bioregulation, Biomedical Research Center, Osaka University Medical School, Suita, Japan.
Tanaka
T
T
Monden
M
M
Miyasaka
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D016466:CHO Cells; D019556:COS Cells; D002448:Cell Adhesion; D002478:Cells, Cultured; D006224:Cricetinae; D019040:E-Selectin / Q000276:immunology*; D004730:Endothelium, Vascular / Q000166:cytology; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D018922:HL-60 Cells; D006801:Humans; D037102:Lectins / Q000276:immunology; D051379:Mice; D019007:P-Selectin / Q000276:immunology*
D000911:Antibodies, Monoclonal; D019040:E-Selectin; D018985:Epitopes, B-Lymphocyte; D037102:Lectins; D019007:P-Selectin