A subset of anti-CD21 antibodies promote the rescue of germinal center B cells from apoptosis.
Germinal center cells (GCC) are programmed to die by apoptosis unless they receive a positive signal for rescue. The primary signal in vivo is believed to be dependent on interaction with antigen held as immune complexes on follicular dendritic cells (FDC), a subset of which express large amounts of CD23, a low-affinity receptor for IgE. Recombinant soluble CD23 (sCD23) and interleukin-1 have been found to potentiate the survival of GCC in vitro. Recently, CD23 was shown to interact specifically with a ligand other than IgE, namely CD21 (CR2/Epstein-Barr virus receptor). In the present study, we show that a subset of anti-CD21 monoclonal antibodies behave similarly to soluble CD23 in their effect on GCC inasmuch as they: (i) diminish the occurrence of apoptosis; (ii) promote a plasmacytoid appearance in rescued cells; (iii) up-regulate expression of the Bcl-2 proto-oncogene. These findings indicate that FDC-derived CD23 exerts its effects on GCC via CD21.
Bonnefoy
J Y
JY
Immunology Section, Glaxo Institute for Molecular Biology, Plan-les-Ouates/Geneva, Switzerland.
Henchoz
S
S
Hardie
D
D
Holder
M J
MJ
Gordon
J
J
D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D017209:Apoptosis; D016175:B-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology; D002454:Cell Differentiation; D002470:Cell Survival; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D014066:Palatine Tonsil / Q000166:cytology*; D000090063:Proto-Oncogene Mas; D017464:Receptors, Complement 3d / Q000276:immunology*
D000911:Antibodies, Monoclonal; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D017464:Receptors, Complement 3d