JVI Figure table search 04
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Roccasecca, R.
Right arrow Articles by Nicosia, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Roccasecca, R.
Right arrow Articles by Nicosia, A.
Journal of Virology, February 2003, p. 1856-1867, Vol. 77, No. 3
0022-538X/03/$08.00+0     DOI: 10.1128/JVI.77.3.1856-1867.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Binding of the Hepatitis C Virus E2 Glycoprotein to CD81 Is Strain Specific and Is Modulated by a Complex Interplay between Hypervariable Regions 1 and 2

RosaMaria Roccasecca,1 Helenia Ansuini,1 Alessandra Vitelli,1 Annalisa Meola,1 Elisa Scarselli,1 Stefano Acali,1 Monica Pezzanera,1 Bruno Bruni Ercole,1 Jane McKeating,2 Asutosh Yagnik,1 Armin Lahm,1 Anna Tramontano,1,{dagger} Riccardo Cortese,1 and Alfredo Nicosia1*

Istituto di Ricerche di Biologia Molecolare P. Angeletti, 00040 Pomezia (Rome), Italy,1 Center for the Study of Hepatitis C, Rockefeller University, New York, New York 100212

Received 24 June 2002/ Accepted 28 October 2002

The envelope glycoprotein E2 of hepatitis C virus (HCV) is the target of neutralizing antibodies and is presently being evaluated as an HCV vaccine candidate. HCV binds to human cells through the interaction of E2 with the tetraspanin CD81, a putative viral receptor component. We have analyzed four different E2 proteins from 1a and 1b viral isolates for their ability to bind to recombinant CD81 in vitro and to the native receptor displayed on the surface of Molt-4 cells. A substantial difference in binding efficiency between these E2 variants was observed, with proteins derived from 1b subtypes showing significantly lower binding than the 1a protein. To elucidate the mechanism of E2-CD81 interaction and to identify critical regions responsible for the different binding efficiencies of the E2 variants, several mutants were generated in E2 protein regions predicted by computer modeling to be exposed on the protein surface. Functional analysis of these E2 derivatives revealed that at least two distinct domains are responsible for interaction with CD81. A first segment centered around amino acid residues 613 to 618 is essential for recognition, while a second element including the two hypervariable regions (HVRs) modulates E2 receptor binding. Binding inhibition experiments with anti-HVR monoclonal antibodies confirmed this mapping and supported the hypothesis that a complex interplay between the two HVRs of E2 is responsible for modulating receptor binding, possibly through intramolecular interactions. Finally, E2 proteins from different isolates displayed a profile of binding to human hepatic cells different from that observed on Molt-4 cells or isolated recombinant CD81, indicating that additional factors are involved in viral recognition by target liver cells.


* Corresponding author. Mailing address: Istituto di Ricerche di Biologia Molecolare P. Angeletti, Via Pontina Km 30.600, 00040 Pomezia (Rome), Italy. Phone: 39-06-91093290. Fax: 39-06-91093654. E-mail: alfredo_nicosia{at}merck.com.

{dagger} Present address: Department of Biochemical Sciences A. Rossi Fanelli, University of Rome La Sapienza, 00185 Rome, Italy.


Journal of Virology, February 2003, p. 1856-1867, Vol. 77, No. 3
0022-538X/03/$08.00+0     DOI: 10.1128/JVI.77.3.1856-1867.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.




This article has been cited by other articles:




Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Mol. Cell. Biol. Microbiol. Mol. Biol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS

Copyright © 2003 by the American Society for Microbiology. All rights reserved.