Determinants of Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Activation by Soluble CD4 and Monoclonal Antibodies
- Nancy Sullivan1,2,
- Ying Sun1,
- James Binley3,4,
- Juliette Lee1,
- Carlos F. Barbas III3,
- Paul W. H. I. Parren3,
- Dennis R. Burton3, and
- Joseph Sodroski1,2 *
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Department of Pathology, Harvard Medical School,1 and
- Department of Cancer Biology, Harvard School of Public Health,2Boston, Massachusetts 02115;
- Departments of Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, California 920373; and
- Aaron Diamond AIDS Research Center, New York University School of Medicine, New York, New York 100164
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Fig. 1.Effects of monoclonal antibodies on infection by viruses with HXBc2 or YU2 envelope glycoproteins. Recombinant viruses bearing the HXBc2 or YU2 envelope glycoproteins were produced in COS-1 cells and incubated with monoclonal antibodies directed against a CD4-induced epitope (17b), the CD4BS (1.5e), or the V3 loop (loop 2). CAT activity was measured 72 h after the addition of Molt 4 clone 8 target cells and is expressed as a percentage of the CAT activity in samples containing no antibody. The baseline conversions of chloramphenicol to acetylated forms for the HXBc2 and YU2 viruses in the absence of added antibody were 36 and 8%, respectively.
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Fig. 2.Effects of an Fab fragment on infection of HIV-1 isolates with different envelope glycoproteins. Recombinant viruses bearing the HXBc2 or YU2 envelope glycoproteins were produced in COS-1 cells and incubated with an Fab directed against the V3 loop (DO142-10). CAT activity, expressed as a percentage of the CAT activity in control samples containing no antibody, was measured 72 h after the addition of PBMC target cells. The baseline CAT conversions for HXBc2 and YU2 were 29 and 8%, respectively.
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Fig. 3.Effects of the 17b antibody on infection of viruses with chimeric HXBc2-YU2 envelope glycoproteins. Recombinant viruses bearing the HXBc2 or chimeric envelopes containing variable loop changes (A) were produced in COS-1 cells and incubated for 90 min with a monoclonal antibody directed against the CD4-induced epitope 17b (B) or sCD4 (C). PBMC target cells were added, and CAT activity, expressed as a percentage of the CAT activity in samples containing no antibody, was measured 72 h later. The baseline conversions of chloramphenicol to acetylated forms in the absence of 17b for the different viruses were as follows: HXBc2, 56%; YU2 V3, 10%; YU2 V1/V2, 30%; YU2 V1/V2/V3, 24%; and ΔV1/V2 YU2 V3, 40%.
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Fig. 4.Effects of MIP-1β on YU2 virus infection in the absence and presence of 17b antibody. Recombinant virions bearing the YU2 envelope glycoprotein were incubated with either MIP-1β alone or MIP-1β plus F105 for 90 min at 37°C. PBMC target cells were added, and CAT activity, expressed as a percentage of CAT conversion relative to samples containing no MIP-1β, was measured after 72 h.
- Copyright © 1998 American Society for Microbiology
