Open AccessMonoclonal antibodies VTB‐E3, IB5 and HB9 to the leucocyte/epithelial antigen CD24 resemble BA‐1 in recognizing sialic acid‐dependent epitope(s). Evidence that VIB‐E3 recognizes NeuAcα2‐6GalNAc and NeuAcα2‐6Gal sequences
Author(s) -
LARKIN M.,
KNAPP W.,
STOLL M. S.,
MEHMET H.,
FEIZI T.
Publication year - 1991
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1111/j.1365-2249.1991.tb05763.x
Subject(s) - epitope , monoclonal antibody , sialic acid , glycoprotein , sialoglycoprotein , antibody , mucin , antigen , oligosaccharide , biochemistry , microbiology and biotechnology , neuraminidase , chemistry , biology , immunology , enzyme
SUMMARY The specificities of seven monoclonal antibodies to the human B cell differentiation marker CD24 have been investigated with respect to sialic acid containing carbohydrates. These are antibodies HB8, HB9, VIB‐C5, VIB‐E3, ALIa, LC66 and IB5, which are known to bind to polydisperse sialoglycoprotein(s) on Nalm‐6 B lymphoblastoid cells. Three of the antibodies, HB9, VIB‐E3 and IB5, have been found to resemble the first described antibody in this series, BA‐1, in binding also to bovine submaxillary mucin. As with BA‐1. the binding of the antibodies is abolished or reduced markedly after desialylation of the epithelial glycoprotein, and the binding to neuraminidase‐treated Nalm‐6 cells is also reduced. There is evidence for the involvement of non‐O‐acetylated sialic acid in the determinants recognized by these antibodies, since there is a substantially enhanced binding following mild‐alkali treatment of the epithelial mucin which removes O‐acetyl groups. One of the antibodies. VIB‐E3. is deduced to recognize the oligosaccharide sequences NeuAcα2‐6GalNAc and NeuAcα2‐6Gal as part of larger antigenic structures. This conclusion has been reached from the results of inhibition‐of‐binding experiments using a series of structurally defined sialo‐oligosaccharides and direct binding experiments using oligosaccharides chemically linked to lipid (neoglycolipids).