Epitope mapping and characterization of a novel CD4-induced human monoclonal antibody capable of neutralizing primary HIV-1 strains

Authors

Shi-Hua Xiang, Harvard Medical SchoolFollow
Liping Wang, Harvard Medical School
Mariam Abreu, Harvard Medical School
Chih-Chin Huang, National Institutes of Health
Peter D. Kwong, National Institutes of Health
Eric Rosenberg, Harvard Medical School
James E. Robinson, Tulane University Medical Center
Joseph Sodroski, Harvard Medical SchoolFollow

Document Type

Article

Date of this Version

2003

Comments

Published in Virology 315 (2003) 124–134, doi:10.1016/S0042-6822(03)00521-X

Abstract

Human immunodeficiency virus (HIV-1) enters target cells by binding its gp120 exterior envelope glycoprotein to CD4 and one of the chemokine receptors, CCR5 or CXCR4. CD4-induced (CD4i) antibodies bind gp120 more efficiently after CD4 binding and block the interaction with the chemokine receptor. Examples of CD4i antibodies are limited, and the prototypes of the CD4i antibodies exhibit only weak neutralizing activity against primary, clinical HIV-1 isolates. Here we report the identification of a novel antibody, E51, that exhibits CD4-induced binding to gp120 and neutralizes primary HIV-1 more efficiently than the prototypic CD4i antibodies. The E51 antibody blocks the interaction of gp120–CD4 complexes with CCR5 and binds to a highly conserved, basic gp120 element composed of the β19-strand and surrounding structures. Thus, on primary HIV-1 isolates, this gp120 region, which has been previously implicated in chemokine receptor binding, is accessible to a subset of CD4i antibodies.