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 Zwick, M. B.
Right arrow Articles by Burton, D. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Zwick, M. B.
Right arrow Articles by Burton, D. R.

 Previous Article  |  Next Article 

Journal of Virology, May 2003, p. 5863-5876, Vol. 77, No. 10
0022-538X/03/$08.00+0     DOI: 10.1128/JVI.77.10.5863-5876.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Molecular Features of the Broadly Neutralizing Immunoglobulin G1 b12 Required for Recognition of Human Immunodeficiency Virus Type 1 gp120

Michael B. Zwick,1 Paul W. H. I. Parren,1,{dagger} Erica O. Saphire,1,2 Sarah Church,1 Meng Wang,1 Jamie K. Scott,3 Philip E. Dawson,4,5 Ian A. Wilson,2,5 and Dennis R. Burton1*

Departments of Immunology,1 Molecular Biology,2 Cell Biology,4 The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037,5 Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada3

Received 5 August 2002/ Accepted 14 February 2003

IgG1 b12 is a broadly neutralizing antibody against human immunodeficiency virus type 1 (HIV-1). The epitope recognized by b12 overlaps the CD4 receptor-binding site (CD4bs) on gp120 and has been a target for vaccine design. Determination of the three-dimensional structure of immunoglobulin G1 (IgG1) b12 allowed modeling of the b12-gp120 interaction in which the protruding third complementarity-determining region (CDR) of the heavy chain (H3) was crucial for antibody binding. In the present study, extensive mutational analysis of the antigen-binding site of Fab b12 was carried out to investigate the validity of the model and to identify residues important for gp120 recognition and, by inference, key to the anti-HIV-1 activity of IgG1 b12. In all, 50 mutations were tested: 40 in H3, 4 each in H2 and L1, and 2 in L3. The results suggest that the interaction of gp120 with H3 of b12 is crucially dependent not only on a Trp residue at the apex of the H3 loop but also on a number of residues at the base of the loop. The arrangement of these residues, including aromatic side chains and side chains that hydrogen bond across the base of the loop, may rigidify H3 for penetration of the recessed CD4-binding cavity. The results further emphasize the importance to gp120 binding of a Tyr residue at the apex of the H2 loop that forms a second finger-like structure and a number of Arg residues in L1 that form a positively charged, shelf-like structure. In general, the data are consistent with the b12-gp120 interaction model previously proposed. At the gene level, somatic mutation is seen to be crucial for the generation of many of the structural features described. The Fab b12 mutants were also tested against the b12 epitope-mimic peptide B2.1, and the reactivity profile had many similarities but also significant differences from that observed for gp120. The paratope map of b12 may facilitate the design of molecules that are able to elicit b12-like activities.


* Corresponding author. Mailing address: Department of Immunology (IMM-2), The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037. Phone: (858) 784-9298. Fax: (858) 784-8360. E-mail: burton{at}scripps.edu.

{dagger} Present address: Genmab, 3584 CK Utrecht, The Netherlands.


Journal of Virology, May 2003, p. 5863-5876, Vol. 77, No. 10
0022-538X/03/$08.00+0     DOI: 10.1128/JVI.77.10.5863-5876.2003
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.