Title: Panels of HIV-1 Subtype C Env Reference Strains for Standardized Neutralization Assessments

Abstract

In the search for effective immunologic interventions to prevent and treat HIV-1 infection, standardized reference reagents are a cost-effective way to maintain robustness and reproducibility among immunological assays. To support planned and ongoing studies where clade C predominates, here we describe three virus panels, chosen from 200 well-characterized clade C envelope (Env)-pseudotyped viruses from early infection. All 200 Envs were expressed as a single round of replication pseudoviruses and were tested to quantify neutralization titers by 16 broadly neutralizing antibodies (bnAbs) and sera from 30 subjects with chronic clade C infections. We selected large panels of 50 and 100 Envs either to characterize cross-reactive breadth for sera identified as having potent neutralization activity based on initial screening or to evaluate neutralization magnitude-breadth distributions of newly isolated antibodies. We identified these panels by downselection after hierarchical clustering of bnAb neutralization titers. The resulting panels represent the diversity of neutralization profiles throughout the range of virus sensitivities identified in the original panel of 200 viruses. A small 12-Env panel was chosen to screen sera from vaccine trials or natural-infection studies for neutralization responses. We considered panels selected by previously described methods but favored a computationally informed method that enabled selection of virusesmore » representing diverse neutralization sensitivity patterns, given that we do nota prioriknow what the neutralization-response profile of vaccine sera will be relative to that of sera from infected individuals. The resulting 12-Env panel complements existing panels. Use of standardized panels enables direct comparisons of data from different trials and study sites testing HIV-1 clade C-specific products. HIV-1 group M includes nine clades and many recombinants. Clade C is the most common lineage, responsible for roughly half of current HIV-1 infections, and is a focus for vaccine design and testing. Standard reference reagents, particularly virus panels to study neutralization by antibodies, are crucial for developing cost-effective and yet rigorous and reproducible assays against diverse examples of this variable virus. We developed clade C-specific panels for use as standardized reagents to monitor complex polyclonal sera for neutralization activity and to characterize the potency and breadth of cross-reactive neutralization by monoclonal antibodies, whether engineered or isolated from infected individuals. We chose from 200 southern African, clade C envelope-pseudotyped viruses with neutralization titers against 16 broadly neutralizing antibodies and 30 sera from chronic clade C infections. We selected panels to represent the diversity of bnAb neutralization profiles and Env neutralization sensitivities. Finally, use of standard virus panels can facilitate comparison of results across studies and sites.« less

Authors:

Hraber, Peter  ^[1];

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Rademeyer, Cecilia ^[2]; Williamson, Carolyn ^[2]; Seaman, Michael S. ^[3]; Gottardo, Raphael ^[4]; Tang, Haili ^[5]; Greene, Kelli ^[5]; Gao, Hongmei ^[5]; LaBranche, Celia ^[5]; Mascola, John R. ^[6]; Morris, Lynn ^[7]; Montefiori, David C. ^[5]; Korber, Bette ^[8]

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Univ. of Cape Town and NHLS, Cape Town (South Africa). Division of Medical Virology & Inst. of Infectious Diseases and Molecular Medicine
3. Harvard Medical School, Boston, MA (United States). Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center
4. Fred Hutchinson Cancer Research Center, Seattle, WA (United States). Vaccine and Infectious Disease Division
5. Duke Univ., Durham, NC (United States). Medical Center, Dept. of Surgery
6. National Inst. of Health (NIH), Bethesda, MD (United States). Vaccine Research Center, National Inst. of Allergy and Infectious Diseases
7. National Inst. for Communicable Diseases, Johannesburg (South Africa)
8. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); New Mexico Consortium, Los Alamos, NM (United States)

Publication Date:

Wed Jul 26 00:00:00 EDT 2017

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

Bill & Melinda Gates Foundation; National Institutes of Health (NIH); South African Government Department of Science and Technology

OSTI Identifier:

1392803

Report Number(s):

LA-UR-16-25426
Journal ID: ISSN 0022-538X

Grant/Contract Number:  

AC52-06NA25396; 38619; 1032144; 1146996; AI51794; 67385; D43TW00231

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Virology

Additional Journal Information:

Journal Volume: 91; Journal Issue: 19; Journal ID: ISSN 0022-538X

Publisher:

American Society for Microbiology

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; Biological Science