Enhancement of Infectivity of a Non-Syncytium Inducing HIV-1 by sCD4 and by Human Antibodies That Neutralize Syncytium Inducing HIV-1

Scand J Immunol. 1995 Jan;41(1):18-22. doi: 10.1111/j.1365-3083.1995.tb03528.x.


Enhancement of virus infectivity after sCD4 treatment has been documented for SIVagm and HIV-2. It has been suggested that a similar phenomenon may play a role in HIV-1 infection. In the present study we have analysed biological activities of virus neutralizing polyclonal and monoclonal human antibodies and of sCD4, towards HIV-1 chimeras with envelope proteins derived from one donor, which display different biological phenotypes. The antibodies, which recognize the V3 and/or the CD4 binding domains of the glycoproteins of these viruses and also sCD4 showed different levels of virus neutralizing activity toward the syncytium inducing HIV-1 strains. In contrast, they all dramatically enhanced the infectivity of an HIV-1 chimera with an envelope glycoprotein displaying the non-syncytium-inducing phenotype. Given the relatively conserved nature of non-syncytium-inducing HIV-1 surface glycoproteins early after infection, these data suggest a major role for antibody mediated enhancement of virus infectivity in the early pathogenesis of HIV-1 infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Antibody Affinity
  • CD4 Antigens / metabolism*
  • Cell Fusion
  • Gene Products, env / immunology
  • HIV Antibodies / immunology*
  • HIV-1 / immunology
  • HIV-1 / pathogenicity*
  • Humans
  • In Vitro Techniques
  • Neutralization Tests


  • Antibodies, Monoclonal
  • CD4 Antigens
  • Gene Products, env
  • HIV Antibodies