TY - JOUR
T1 - In vitro IgE inhibition in B cells by anti-CD23 monoclonal antibodies is functionally dependent on the immunoglobulin Fc domain
AU - Nakamura, Takehiko
AU - Kloetzer, William S.
AU - Brams, Peter
AU - Hariharan, Kandasamy
AU - Chamat, Soulaima
AU - Cao, Xianjun
AU - Labarre, Michael J.
AU - Chinn, Paul C.
AU - Morena, Ron A.
AU - Shestowsky, William S.
AU - Li, Yan Ping
AU - Chen, Agnes
AU - Reff, Mitchell E.
PY - 2000/2/1
Y1 - 2000/2/1
N2 - CD23, the low affinity receptor for IgE (FcεRII), is involved in regulation of IgE synthesis by B-lymphocytes. Five monoclonal antibodies to human CD23 were generated from cynomolgus macaques immunized with purified soluble CD23 (sCD23). Four of the five primate antibodies blocked the binding of IgE complexes to CD23 positive cells and also inhibited the production of IgE in vitro by IL-4 induced human peripheral blood mononuclear cells (PBMC). The variable domains of several primate antibodies were utilized to construct chimeric macaque/human (PRIMATIZED®) monoclonal antibodies. PRIMATIZED® p5E8G1, containing human gamma 1 constant region, inhibited IgE production in vitro as efficiently as the parent primate antibody, but the human gamma 4 constant version, PRIMATIZED® p5E8G4, was not as effective in IgE inhibition. An F(ab')2 of p5E8G1 did not inhibit IgE production but did interfere with IgE inhibition by the intact anti-CD23 antibody in a dose dependent fashion. The murine monoclonal antibody MHM6 recognizes human CD23 at a different epitope than primate antibody 5E8, and inhibits IgE production by IL-4 induced PBMC. As with the F(ab')2 of p5E8G1, the F(ab')2 of MHM6 also failed to inhibit IgE production. These data imply that the mechanism by which anti-CD23 antibodies inhibit IgE production requires cross-linking of CD23 to an IgG receptor. These data also imply that neither bivalent cross- linking of CD23 alone or inhibition of CD23 binding to its natural ligands is sufficient to inhibit IgE production. (C) 2000 International Society for Immunopharmacology.
AB - CD23, the low affinity receptor for IgE (FcεRII), is involved in regulation of IgE synthesis by B-lymphocytes. Five monoclonal antibodies to human CD23 were generated from cynomolgus macaques immunized with purified soluble CD23 (sCD23). Four of the five primate antibodies blocked the binding of IgE complexes to CD23 positive cells and also inhibited the production of IgE in vitro by IL-4 induced human peripheral blood mononuclear cells (PBMC). The variable domains of several primate antibodies were utilized to construct chimeric macaque/human (PRIMATIZED®) monoclonal antibodies. PRIMATIZED® p5E8G1, containing human gamma 1 constant region, inhibited IgE production in vitro as efficiently as the parent primate antibody, but the human gamma 4 constant version, PRIMATIZED® p5E8G4, was not as effective in IgE inhibition. An F(ab')2 of p5E8G1 did not inhibit IgE production but did interfere with IgE inhibition by the intact anti-CD23 antibody in a dose dependent fashion. The murine monoclonal antibody MHM6 recognizes human CD23 at a different epitope than primate antibody 5E8, and inhibits IgE production by IL-4 induced PBMC. As with the F(ab')2 of p5E8G1, the F(ab')2 of MHM6 also failed to inhibit IgE production. These data imply that the mechanism by which anti-CD23 antibodies inhibit IgE production requires cross-linking of CD23 to an IgG receptor. These data also imply that neither bivalent cross- linking of CD23 alone or inhibition of CD23 binding to its natural ligands is sufficient to inhibit IgE production. (C) 2000 International Society for Immunopharmacology.
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U2 - 10.1016/S0192-0561(99)00068-5
DO - 10.1016/S0192-0561(99)00068-5
M3 - Article
C2 - 10684997
AN - SCOPUS:0033984514
VL - 22
SP - 131
EP - 141
JO - International Immunopharmacology
JF - International Immunopharmacology
SN - 1567-5769
IS - 2
ER -