Polymerase chain reaction-based assay for antibody-mediated neutralization of HIV-1 reveals a population of nonneutralized virus undetected by conventional p24 assay

J Acquir Immune Defic Syndr. 2000 Jul 1;24(3):203-10. doi: 10.1097/00126334-200007010-00002.

Abstract

To be successful with strategies involving passive immunization or the generation of neutralizing antibodies against HIV, it is crucial that we improve our understanding of the process of antibody-mediated HIV neutralization. We have used a neutralization assay based on polymerase chain reaction (PCR) that is more rapid and sensitive than the conventional p24 neutralization assay based on enzyme-linked immunosorbent assay (ELISA). PCR assays permit measurement of the number of infectious events and can detect small amounts of HIV-1 only a few days postinfection. In these studies, the human anti-V3 monoclonal antibody 694/98-D was used to neutralize the infectivity of the laboratory isolate HIVIIIB for CEM-SS cells. 8E5/LAV cells, which contain a single integrated copy of proviral DNA per cell, served as a standard to determine the amount of HIV-1 copies in infected CEM-SS cells. Evaluation of antibody-mediated neutralization was possible at 2 to 3 days postinfection, at a time when p24 readouts were not conclusive. We achieved >95% neutralization of HIVIIIB, and of its molecular clone HXB2, using the monoclonal antibody 694/98-D. This degree of neutralization is probably highly significant in vivo. Nevertheless, a small amount of both HIVIIIB and HXB2 ( approximately 5%) escapes neutralization and can consistently be detected after a few days by this sensitive assay. Experiments with different anti-HIV monoclonal antibodies and viruses showed that the assay could be applied to anti-V3 as well as anti-CD4 binding domain antibodies as well as HIV laboratory strains or primary isolates.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Antibodies, Monoclonal / immunology*
  • Antibodies, Monoclonal / pharmacology
  • Antigens, Viral / immunology
  • Blotting, Southern
  • DNA, Viral / analysis
  • Dose-Response Relationship, Drug
  • Enzyme-Linked Immunosorbent Assay
  • HIV Antibodies / immunology*
  • HIV Antibodies / pharmacology
  • HIV Core Protein p24 / analysis
  • HIV Envelope Protein gp120 / immunology
  • HIV-1 / drug effects
  • HIV-1 / immunology*
  • HIV-1 / isolation & purification*
  • Humans
  • Jurkat Cells
  • Neutralization Tests
  • Peptide Fragments / immunology
  • Polymerase Chain Reaction / methods*
  • Proviruses / genetics
  • Reproducibility of Results
  • Sensitivity and Specificity

Substances

  • Antibodies, Monoclonal
  • Antigens, Viral
  • DNA, Viral
  • HIV Antibodies
  • HIV Core Protein p24
  • HIV Envelope Protein gp120
  • HIV envelope protein gp120 (305-321)
  • Peptide Fragments