Fc epsilon receptors on rat B-lymphocytes: specificity and binding kinetics.
The binding kinetics of radiolabelled rat IgE to Fc epsilon receptors (R) of rat B-cells have already been studied in IgE-stimulated animals. The receptors expressed after Nippostrongylus brasiliensis infection or 2 injections of 5 mg IgE/100 g body wt were class-specific: IgE binding was not hindered by rat IgM, IgD, IgA, IgG1, IgG2a, IgG2b and IgG2c in immunocompetitive-binding assays. The rat B-cell Fc epsilon R were not species-specific, since mouse IgE competes with rat IgE for binding to these receptors. The apparent number of Fc epsilon R on rat mesenteric lymph node B-cells varied with temp and was 1.1-2.4 X 10(5) at 4 degrees C and 5.9-7.7 X 10(5) at 37 degrees C. The experimental Ka was not influenced by temp and had an average value of 1.38 X 10(8) M-1. At 4 degrees C the IgE binding to B-cell Fc epsilon R had an association rate of 4.9 X 10(3) M-1 sec-1 and a dissociation rate of 4.65 X 10(-5) sec-1. After a very strong stimulation produced by injecting 5 mg IgE/100 g body wt every 24 hr for 5 days, the equilibrium binding curve became diphasic, indicating a probable heterogeneity of the B-cell Fc epsilon R.
D000818:Animals; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology*; D007141:Immunoglobulin Fc Fragments / Q000276:immunology*; D007128:Immunoglobulin Fragments / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000276:immunology*; D007139:Immunoglobulin epsilon-Chains / Q000276:immunology*; D007700:Kinetics; D051381:Rats; D011961:Receptors, Fc / Q000276:immunology*; D017455:Receptors, IgE; D011971:Receptors, Immunologic / Q000276:immunology*
D007141:Immunoglobulin Fc Fragments; D007128:Immunoglobulin Fragments; D007143:Immunoglobulin Heavy Chains; D007139:Immunoglobulin epsilon-Chains; D011961:Receptors, Fc; D017455:Receptors, IgE; D011971:Receptors, Immunologic