Immune response to phosphorylcholine. III. Requirement of the Fc portion and equal effectiveness of IgG subclasses in anti-receptor antibody-induced suppression.
Anti-idiotypic antibody raised against the BALB/c myeloma proteins TEPC-15 or HOPC-8 inhibits induction of the immune response to phosphorylcholine (PC). (Fab')2 and Fab' fragments from anti-idiotype serum were prepared and anti-idiotypic antibody was purified by absorption and elution from idiotype or anti-IgG subclass immunoabsorbents. The parent material, the purified anti-idiotypic antibodies and the Fab' fragments were assayed for: i) binding to the idiotype by using a sensitive radioimmunoassay, and ii) specific suppression of the response to PC in vitro. The correlation of binding to suppression was very similar for anti-idiotype serum and both kinds of purified antibody. However, the Fab' fragments only bound to the idiotype and did not suppress. These findings indicate that the Fc portion of anti-idiotypic anti-receptor antibody (ARA) is essential for inducing suppression but that ARA-induced suppression is independent of the IgG isotype. It is postulated that idiotype suppression is mediated by the interaction of anti-idiotype with the antigen receptor and the Fc receptor thereby cross-linking both receptors.
D000818:Animals; D000906:Antibodies / Q000302:isolation & purification; D000917:Antibody Formation; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D002794:Choline / Q000031:analogs & derivatives*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007140:Immunoglobulin Fab Fragments / Q000302:isolation & purification; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G / Q000302:isolation & purification; D007165:Immunosuppression Therapy; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D010767:Phosphorylcholine / Q000276:immunology / Q000494:pharmacology*
D000906:Antibodies; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D010767:Phosphorylcholine; D002794:Choline