Evidence of IgG-mediated enhancement of the antibody response in vivo without complement activation via the classical pathway.
The complement (C) dependency of IgG-mediated enhancement of the antibody response was investigated by immunizing mice with trinitrophenyl-coupled keyhole limpet hemocyanin (TNP-KLH) and either a C-activating TNP-specific monoclonal IgG2a antibody (Hy-1.2) or a mutant, non-C-activating variant of Hy-1.2 (M12). Hy-1.2 as well as M12 efficiently enhanced the anti-KLH response, although Hy-1.2 was more active. In addition, also a naturally non-C-activating TNP-specific IgG1 antibody enhanced the response to TNP-coupled bovine serum albumin. Moreover, C-activating IgG could enhance the antibody response in mice depleted of C3 by treatment with cobra venom factor. These findings suggest that the classical pathway of C activation is not required for IgG-mediated enhancement.
Wiersma
E J
EJ
Department of Immunology, BMC, Uppsala School of Medicine, Sendai, Sweden.
Nose
M
M
Heyman
B
B
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000917:Antibody Formation; D003176:Complement C3 / Q000502:physiology; D003171:Complement Pathway, Classical; D004546:Elapid Venoms / Q000494:pharmacology; D006433:Hemocyanins / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D013745:Tetanus Toxoid / Q000276:immunology; D014301:Trinitrobenzenes / Q000276:immunology
D000911:Antibodies, Monoclonal; D003176:Complement C3; D004546:Elapid Venoms; D007074:Immunoglobulin G; D013745:Tetanus Toxoid; D014301:Trinitrobenzenes; C016310:cobra venom factor; D006433:Hemocyanins