Evidence of IgG-mediated enhancement of the antibody response in vivo without complement activation via the classical pathway

Eur J Immunol. 1990 Dec;20(12):2585-9. doi: 10.1002/eji.1830201209.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology
  • Antibody Formation*
  • Complement C3 / physiology
  • Complement Pathway, Classical*
  • Elapid Venoms / pharmacology
  • Hemocyanins / immunology
  • Immunoglobulin G / immunology*
  • Male
  • Mice
  • Mice, Inbred CBA
  • Tetanus Toxoid / immunology
  • Trinitrobenzenes / immunology


  • Antibodies, Monoclonal
  • Complement C3
  • Elapid Venoms
  • Immunoglobulin G
  • Tetanus Toxoid
  • Trinitrobenzenes
  • cobra venom factor
  • Hemocyanins