Analysis of memory B cell responses and isolation of novel monoclonal antibodies with neutralizing breadth from HIV-1-infected individuals.

Davide Corti,David C Montefiori,David Jarrossay,Corinna Pade,Hanna Dreja,Robin A Weiss,Áine Mcknight,Antonio Lanzavecchia,Quentin J Sattentau,Johannes P M Langedijk,Jonathan L Heeney,Andreas Hinz,Michael S Seaman,Simon A Jeffs,Chiara Silacci,Betty Willems,Federica Sallusto,Debora Pinna,Chloe Orkin,Fabrizia Vanzetta,Maria J Zekveld,Blanca Fernandez-Rodriguez ,Winfríed Weissenhorn ,Eithne O’sullivan ,Sunita S Balla-Jhagjhoorsingh ,David A Davis

doi:10.1371/journal.pone.0008805

Abstract

BackgroundThe isolation of human monoclonal antibodies (mAbs) that neutralize a broad spectrum of primary HIV-1 isolates and the characterization of the human neutralizing antibody B cell response to HIV-1 infection are important goals that are central to the design of an effective antibody-based vaccine.Methods and FindingsWe immortalized IgG+ memory B cells from individuals infected with diverse clades of HIV-1 and selected on the basis of plasma neutralization profiles that were cross-clade and relatively potent. Culture supernatants were screened using various recombinant forms of the envelope glycoproteins (Env) in multiple parallel assays. We isolated 58 mAbs that were mapped to different Env surfaces, most of which showed neutralizing activity. One mAb in particular (HJ16) specific for a novel epitope proximal to the CD4 binding site on gp120 selectively neutralized a multi-clade panel of Tier-2 HIV-1 pseudoviruses, and demonstrated reactivity that was comparable in breadth, but distinct in neutralization specificity, to that of the other CD4 binding site-specific neutralizing mAb b12. A second mAb (HGN194) bound a conserved epitope in the V3 crown and neutralized all Tier-1 and a proportion of Tier-2 pseudoviruses tested, irrespective of clade. A third mAb (HK20) with broad neutralizing activity, particularly as a Fab fragment, recognized a highly conserved epitope in the HR-1 region of gp41, but showed striking assay-dependent selectivity in its activity.ConclusionsThis study reveals that by using appropriate screening methods, a large proportion of memory B cells can be isolated that produce mAbs with HIV-1 neutralizing activity. Three of these mAbs show unusual breadth of neutralization and therefore add to the current panel of HIV-1 neutralizing antibodies with potential for passive protection and template-based vaccine design.

Highlights

Neutralizing antibodies provide one arm of the adaptive immune response against the human immunodeficiency virus type 1 (HIV-1)
Several reports demonstrated that the neutralizing antibody response exerts selective pressure during HIV-1 replication in vivo, which accounts in part for the extensive variation in the env gene observed soon after primary infection [1,2]
Plasma samples were obtained from patients entered into the Antwerp and London cohorts who were infected with a variety of HIV-1 clades

Summary

Introduction

Neutralizing antibodies provide one arm of the adaptive immune response against the human immunodeficiency virus type 1 (HIV-1). It has been anticipated that the identification of broadly neutralizing mAbs from HIV-1 infected individuals, and the characterization of their cognate epitopes will be instrumental in the design of immunogens capable of eliciting such a broad neutralizing response [12]. This idea has led to a major international cooperative effort within consortia of laboratories with complementary expertise in human immunology, structural biology and vaccine design [13,14]. The isolation of human monoclonal antibodies (mAbs) that neutralize a broad spectrum of primary HIV-1 isolates and the characterization of the human neutralizing antibody B cell response to HIV-1 infection are important goals that are central to the design of an effective antibody-based vaccine

Methods

Results

Discussion

Conclusion