Demonstration of a second ligand for the low affinity receptor for immunoglobulin E (CD23) using recombinant CD23 reconstituted into fluorescent liposomes.
Recombinant full-length human CD23 has been incorporated into fluorescent liposomes to demonstrate the existence of a ligand for CD23 that is different from the previously known ligand, immunoglobulin E (IgE). The novel ligand for CD23 is expressed on subsets of normal T cells and B cells as well as on some myeloma cell lines. The interaction of full-length CD23 with its ligand is specifically inhibited by anti-CD23 monoclonal antibodies and by IgE, and it is Ca2+ dependent. Moreover, tunicamycin treatment of a CD23-binding cell line, RPMI 8226, significantly reduced the binding of CD23 incorporated into fluorescent liposomes, and a sugar, fucose-1-phosphate, was found to inhibit CD23-liposome binding to RPMI 8226 cells, suggesting the contribution of sugar structures on the CD23 ligand. In addition, CD23-transfected COS cells were shown to form specific conjugates with the cell line RPMI 8226. These data demonstrate that CD23 interacts with a ligand, which is different from IgE, and that CD23 can be considered as a new surface adhesion molecule involved in cell-cell interactions.
Pochon
S
S
Glaxo Institute for Molecular Biology, Plan-Les-Ouates, Geneva, Switzerland.
Graber
P
P
Yeager
M
M
Jansen
K
K
Bernard
A R
AR
Aubry
J P
JP
Bonnefoy
J Y
JY
D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology / Q000378:metabolism*; D008024:Ligands; D008081:Liposomes / Q000276:immunology / Q000378:metabolism*; D016131:Lymphocyte Subsets / Q000378:metabolism; D011961:Receptors, Fc / Q000276:immunology / Q000378:metabolism*; D017455:Receptors, IgE; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D014415:Tunicamycin / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D005456:Fluorescent Dyes; D008024:Ligands; D008081:Liposomes; D011961:Receptors, Fc; D017455:Receptors, IgE; D011994:Recombinant Proteins; D014415:Tunicamycin; D007073:Immunoglobulin E; D002118:Calcium