Two parallel routes of the complement-mediated antibody-dependent enhancement of HIV-1 infection

AIDS. 1997 Jul;11(8):949-58. doi: 10.1097/00002030-199708000-00002.


Objective: To study the mechanism of the complement-mediated antibody-dependent enhancement (C'-ADE) of HIV infection which may play a significant role in the progression of HIV-disease.

Methods: In vitro complement activating and complement-mediated HIV-infection enhancing abilities of three human anti-gp41 monoclonal antibodies (MAb) were tested. C'-ADE was estimated using HIV-1IIIB and CR2 (CD21)-carrying MT-4 target cells. Normal human serum (NHS), purified C1q, C1q-deficient (C1qD) and C2-deficient (C2D) human sera were applied as complement sources.

Results: All MAb mediated increased C1q binding to solid-phase gp41. All MAb had a marked dose-dependent and strictly complement-mediated HIV-infection enhancing effect. Mixtures of the MAb with purified C1q also significantly increased HIV-1 infection. C1qD serum had a markedly lower enhancing effect than NHS, which could be raised to normal level by addition of purified C1q. Pretreatment of the target cells with anti-CR2 antibodies only partially inhibited the enhancing effect of the MAb plus normal human serum.

Conclusion: These novel findings indicate that besides the well-known facilitation of entry of HIV-1 by the interaction between virus-bound C3 fragments and CR2 present on the target cells, fixation of C1q to intact virions also results in an enhanced productive HIV-1 infection in the MT-4 cell cultures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Complement C1q / immunology*
  • Complement C1q / pharmacology
  • Disease Progression
  • HIV Antibodies / immunology*
  • HIV Envelope Protein gp41 / immunology*
  • HIV Infections / immunology*
  • HIV Infections / physiopathology
  • HIV-1 / immunology*
  • Humans
  • Tumor Cells, Cultured


  • Antibodies, Monoclonal
  • HIV Antibodies
  • HIV Envelope Protein gp41
  • Complement C1q