Redox-triggered infection by disulfide-shackled human immunodeficiency virus type 1 pseudovirions.
We previously described a human immunodeficiency virus type 1 (HIV-1) envelope mutant that introduces a disulfide bridge between the gp120 surface proteins and gp41 transmembrane proteins (J. M. Binley, R. W. Sanders, B. Clas, N. Schuelke, A. Master, Y. Guo, F. Kajumo, D. J. Anselma, P. J. Maddon, W. C. Olson, and J. P. Moore, J. Virol. 74:627-643, 2000). Here we produced pseudovirions bearing the mutant envelope and a reporter gene to examine the mutant's infectious properties. These pseudovirions attach to cells expressing CD4 and coreceptor but infect only when triggered with reducing agent, implying that gp120-gp41 dissociation is necessary for infection. Further studies suggested that virus entry was arrested after CD4 and coreceptor engagement. By measuring the activities of various entry inhibitors against the arrested intermediate, we found that gp120-targeting inhibitors typically act prior to virus attachment, whereas gp41 inhibitors are able to act postattachment. Unexpectedly, a significant fraction of antibodies in HIV-1-positive sera neutralized virus postattachment, suggesting that downstream fusion events and structures figure prominently in the host immune response. Overall, this disulfide-shackled virus is a unique tool with potential utility in vaccine design, drug discovery, and elucidation of the HIV-1 entry process.
Departments of Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA. jbinley@scripps.edu
James M
JM
Binley
Charmagne S
CS
Cayanan
Cheryl
C
Wiley
Norbert
N
Schülke
William C
WC
Olson
Dennis R
DR
Burton
D002460:Cell Line; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism*; D004229:Dithiothreitol / Q000494:pharmacology; D015483:HIV Antibodies / Q000097:blood / Q000276:immunology; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015700:HIV Envelope Protein gp41 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015658:HIV Infections / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008561:Membrane Fusion; D009500:Neutralization Tests; D010084:Oxidation-Reduction; D019713:Receptors, CCR5 / Q000378:metabolism; D019163:Reducing Agents / Q000494:pharmacology; D014771:Virion / Q000235:genetics / Q000472:pathogenicity*
D004220:Disulfides; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D019713:Receptors, CCR5; D019163:Reducing Agents; D004229:Dithiothreitol