1
|
Zhang Y, Zheng S, Zhao W, Mao Y, Cao W, Zeng W, Liu Y, Hu L, Gong M, Cheng J, Chen Y, Yang H. Sequential Analysis of the N/O-Glycosylation of Heavily Glycosylated HIV-1 gp120 Using EThcD-sceHCD-MS/MS. Front Immunol 2021; 12:755568. [PMID: 34745128 PMCID: PMC8567067 DOI: 10.3389/fimmu.2021.755568] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/06/2021] [Indexed: 02/05/2023] Open
Abstract
Deciphering the glycosylation of the viral envelope (Env) glycoprotein is critical for evaluating viral escape from the host’s immune response and developing vaccines and antiviral drugs. However, it is still challenging to precisely decode the site-specific glycosylation characteristics of the highly glycosylated Env proteins, although glycoproteomics have made significant advances in mass spectrometry techniques and data analysis tools. Here, we present a hybrid dissociation technique, EThcD-sceHCD, by combining electron transfer/higher-energy collisional dissociation (EThcD) and stepped collision energy/higher-energy collisional dissociation (sceHCD) into a sequential glycoproteomic workflow. Following this scheme, we characterized site-specific N/O-glycosylation of the human immunodeficiency virus type 1 (HIV-1) Env protein gp120. The EThcD-sceHCD method increased the number of identified glycopeptides when compared with EThcD, while producing more comprehensive fragment ions than sceHCD for site-specific glycosylation analysis, especially for accurate O-glycosite assignment. Finally, eighteen N-glycosites and five O-glycosites with attached glycans were assigned unambiguously from heavily glycosylated gp120. These results indicate that our workflow can achieve improved performance for analysis of the N/O-glycosylation of a highly glycosylated protein containing numerous potential glycosites in one process. Knowledge of the glycosylation landscape of the Env glycoprotein will be useful for understanding of HIV-1 infection and development of vaccines and drugs.
Collapse
Affiliation(s)
- Yong Zhang
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Sichuan Provincial Engineering Laboratory of Pathology in Clinical Application, West China Hospital, Sichuan University, Chengdu, China
| | - Shanshan Zheng
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Wanjun Zhao
- Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yonghong Mao
- Institute of Thoracic Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Wei Cao
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Wenjuan Zeng
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yueqiu Liu
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Liqiang Hu
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Meng Gong
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Sichuan Provincial Engineering Laboratory of Pathology in Clinical Application, West China Hospital, Sichuan University, Chengdu, China
| | - Jingqiu Cheng
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Younan Chen
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Hao Yang
- National Health Commission (NHC) Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Sichuan Provincial Engineering Laboratory of Pathology in Clinical Application, West China Hospital, Sichuan University, Chengdu, China
| |
Collapse
|
2
|
Fries CN, Chen JL, Dennis ML, Votaw NL, Eudailey J, Watts BE, Hainline KM, Cain DW, Barfield R, Chan C, Moody MA, Haynes BF, Saunders KO, Permar SR, Fouda GG, Collier JH. HIV envelope antigen valency on peptide nanofibers modulates antibody magnitude and binding breadth. Sci Rep 2021; 11:14494. [PMID: 34262096 PMCID: PMC8280189 DOI: 10.1038/s41598-021-93702-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/23/2021] [Indexed: 01/02/2023] Open
Abstract
A major challenge in developing an effective vaccine against HIV-1 is the genetic diversity of its viral envelope. Because of the broad range of sequences exhibited by HIV-1 strains, protective antibodies must be able to bind and neutralize a widely mutated viral envelope protein. No vaccine has yet been designed which induces broadly neutralizing or protective immune responses against HIV in humans. Nanomaterial-based vaccines have shown the ability to generate antibody and cellular immune responses of increased breadth and neutralization potency. Thus, we have developed supramolecular nanofiber-based immunogens bearing the HIV gp120 envelope glycoprotein. These immunogens generated antibody responses that had increased magnitude and binding breadth compared to soluble gp120. By varying gp120 density on nanofibers, we determined that increased antigen valency was associated with increased antibody magnitude and germinal center responses. This study presents a proof-of-concept for a nanofiber vaccine platform generating broad, high binding antibody responses against the HIV-1 envelope glycoprotein.
Collapse
Affiliation(s)
- Chelsea N Fries
- Department of Biomedical Engineering, Duke University, 101 Science Dr., Campus, Box 90281, Durham, NC, 27708, USA
| | - Jui-Lin Chen
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Maria L Dennis
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Nicole L Votaw
- Department of Biomedical Engineering, Duke University, 101 Science Dr., Campus, Box 90281, Durham, NC, 27708, USA
| | - Joshua Eudailey
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Brian E Watts
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Kelly M Hainline
- Department of Biomedical Engineering, Duke University, 101 Science Dr., Campus, Box 90281, Durham, NC, 27708, USA
| | - Derek W Cain
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Richard Barfield
- Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Cliburn Chan
- Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, 27710, USA
| | - M Anthony Moody
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Pediatrics, Duke University Medical Center, Duke University School of Medicine, Box 103020, Durham, NC, 27710, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Kevin O Saunders
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Surgery, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Sallie R Permar
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Pediatrics, Duke University Medical Center, Duke University School of Medicine, Box 103020, Durham, NC, 27710, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Pediatrics, New York-Presbyterian/Weill Cornell Medicine, New York, NY, 10065, USA
| | - Genevieve G Fouda
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Pediatrics, Duke University Medical Center, Duke University School of Medicine, Box 103020, Durham, NC, 27710, USA.
| | - Joel H Collier
- Department of Biomedical Engineering, Duke University, 101 Science Dr., Campus, Box 90281, Durham, NC, 27708, USA.
- Department of Immunology, Duke University School of Medicine, Durham, NC, 27710, USA.
| |
Collapse
|
3
|
Sharma VK, Sharma I, Glick J. The expanding role of mass spectrometry in the field of vaccine development. MASS SPECTROMETRY REVIEWS 2020; 39:83-104. [PMID: 29852530 PMCID: PMC7027533 DOI: 10.1002/mas.21571] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/30/2018] [Indexed: 05/09/2023]
Abstract
Biological mass spectrometry has evolved as a core analytical technology in the last decade mainly because of its unparalleled ability to perform qualitative as well as quantitative profiling of enormously complex biological samples with high mass accuracy, sensitivity, selectivity and specificity. Mass spectrometry-based techniques are also routinely used to assess glycosylation and other post-translational modifications, disulfide bond linkage, and scrambling as well as for the detection of host cell protein contaminants in the field of biopharmaceuticals. The role of mass spectrometry in vaccine development has been very limited but is now expanding as the landscape of global vaccine development is shifting towards the development of recombinant vaccines. In this review, the role of mass spectrometry in vaccine development is presented, some of the ongoing efforts to develop vaccines for diseases with global unmet medical need are discussed and the regulatory challenges of implementing mass spectrometry techniques in a quality control laboratory setting are highlighted.
Collapse
Affiliation(s)
| | - Ity Sharma
- Independent CMC ConsultantParamusNew Jersey
| | - James Glick
- Novartis Institutes for BioMedical ResearchEast HanoverNew Jersey
| |
Collapse
|
4
|
Shen X, Laher F, Moodie Z, McMillan AS, Spreng RL, Gilbert PB, Huang Y, Yates NL, Grunenberg N, Juliana McElrath M, Allen M, Pensiero M, Mehra VL, Der Meeren OV, Barnett SW, Phogat S, Gray GE, Bekker LG, Corey L, Tomaras GD. HIV-1 Vaccine Sequences Impact V1V2 Antibody Responses: A Comparison of Two Poxvirus Prime gp120 Boost Vaccine Regimens. Sci Rep 2020; 10:2093. [PMID: 32034163 PMCID: PMC7005751 DOI: 10.1038/s41598-020-57491-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 12/17/2019] [Indexed: 11/09/2022] Open
Abstract
In the RV144 trial, vaccine-induced V1V2 IgG correlated with decreased HIV-1 risk. We investigated circulating antibody specificities in two phase 1 poxvirus prime-protein boost clinical trials conducted in South Africa: HVTN 097 (subtype B/E) and HVTN 100 (subtype C). With cross-subtype peptide microarrays and multiplex binding assays, we probed the magnitude and breadth of circulating antibody responses to linear variable loop 2 (V2) and conformational V1V2 specificities. Antibodies targeting the linear V2 epitope, a correlate of decreased HIV-1 risk in RV144, were elicited up to 100% and 61% in HVTN 097 and HVTN 100, respectively. Despite higher magnitude of envelope-specific responses in HVTN 100 compared to HVTN 097 (p’s < 0.001), the magnitude and positivity for V2 linear epitope and V1V2 proteins were significantly lower in HVTN 100 compared to HVTN 097. Meanwhile, responses to other major linear epitopes including the variable 3 (V3) and constant 5 (C5) epitopes were higher in HVTN 100 compared to HVTN 097. Our data reveal substantial differences in the circulating antibody specificities induced by vaccination in these two canarypox prime-protein boost trials. Our findings suggest that the choice of viral sequences in prime-boost vaccine regimens, and potentially adjuvants and immunogen dose, influence the elicitation of V2-specific antibodies.
Collapse
Affiliation(s)
- Xiaoying Shen
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA.
| | - Fatima Laher
- Perinatal HIV Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Soweto, South Africa
| | - Zoe Moodie
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Arthur S McMillan
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Rachel L Spreng
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Peter B Gilbert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Ying Huang
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Nicole L Yates
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Nicole Grunenberg
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - M Juliana McElrath
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Mary Allen
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael Pensiero
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Vijay L Mehra
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Susan W Barnett
- GSK Vaccines (formerly Novartis Vaccines), Cambridge, Massachusetts, USA.,Bill & Melinda Gates Foundation, Seattle, Washington, USA
| | | | - Glenda E Gray
- Perinatal HIV Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Soweto, South Africa.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.,South African Medical Research Council, Cape Town, South Africa
| | - Linda-Gail Bekker
- The Desmond Tutu HIV Centre, University of Cape Town, Cape Town, South Africa
| | - Lawrence Corey
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Georgia D Tomaras
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA. .,Department of Immunology, Duke University School of Medicine, Durham, North Carolina, USA. .,Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA. .,Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA.
| |
Collapse
|
5
|
Clade C HIV-1 Envelope Vaccination Regimens Differ in Their Ability To Elicit Antibodies with Moderate Neutralization Breadth against Genetically Diverse Tier 2 HIV-1 Envelope Variants. J Virol 2019; 93:JVI.01846-18. [PMID: 30651354 DOI: 10.1128/jvi.01846-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/03/2019] [Indexed: 01/09/2023] Open
Abstract
The goals of preclinical HIV vaccine studies in nonhuman primates are to develop and test different approaches for their ability to generate protective immunity. Here, we compared the impact of 7 different vaccine modalities, all expressing the HIV-1 1086.C clade C envelope (Env), on (i) the magnitude and durability of antigen-specific serum antibody responses and (ii) autologous and heterologous neutralizing antibody capacity. These vaccination regimens included immunization with different combinations of DNA, modified vaccinia virus Ankara (MVA), soluble gp140 protein, and different adjuvants. Serum samples collected from 130 immunized monkeys at two key time points were analyzed using the TZM-bl cell assay: at 2 weeks after the final immunization (week 40/41) and on the day of challenge (week 58). Key initial findings were that inclusion of a gp140 protein boost had a significant impact on the magnitude and durability of Env-specific IgG antibodies, and addition of 3M-052 adjuvant was associated with better neutralizing activity against the SHIV1157ipd3N4 challenge virus and a heterologous HIV-1 CRF01 Env, CNE8. We measured neutralization against a panel of 12 tier 2 Envs using a newly described computational tool to quantify serum neutralization potency by factoring in the predetermined neutralization tier of each reference Env. This analysis revealed modest neutralization breadth, with DNA/MVA immunization followed by gp140 protein boosts in 3M-052 adjuvant producing the best scores. This study highlights that protein-containing regimens provide a solid foundation for the further development of novel adjuvants and inclusion of trimeric Env immunogens that could eventually elicit a higher level of neutralizing antibody breadth.IMPORTANCE Despite much progress, we still do not have a clear understanding of how to elicit a protective neutralizing antibody response against HIV-1 through vaccination. There have been great strides in the development of envelope immunogens that mimic the virus particle, but less is known about how different vaccination modalities and adjuvants contribute to shaping the antibody response. We compared seven different vaccines that were administered to rhesus macaques and that delivered the same envelope protein through various modalities and with different adjuvants. The results demonstrate that some vaccine components are better than others at eliciting neutralizing antibodies with breadth.
Collapse
|
6
|
Doran RC, Yu B, Wright M, O'Rourke SM, Yin L, Richardson JM, Byrne G, Mesa KA, Berman PW. Development of a Stable MGAT1 - CHO Cell Line to Produce Clade C gp120 With Improved Binding to Broadly Neutralizing Antibodies. Front Immunol 2018; 9:2313. [PMID: 30344523 PMCID: PMC6182045 DOI: 10.3389/fimmu.2018.02313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/17/2018] [Indexed: 12/27/2022] Open
Abstract
The high rate of new HIV infections, particularly in Sub-Saharan Africa, emphasizes the need for a safe and effective vaccine to prevent acquired immunodeficiency syndrome (AIDS). To date, the only HIV vaccine trial that has exhibited protective efficacy in humans was the RV144 study completed in Thailand. The finding that protection correlated with antibodies to gp120 suggested that increasing the quality or magnitude of the antibody response that recognize gp120 might improve the modest yet significant protection (31.2%) achieved with this immunization regimen. However, the large-scale production of rgp120 suitable for clinical trials has been challenging due, in part, to low productivity and difficulties in purification. Moreover, the antigens that are currently available were produced largely by the same technology used in the early 1990s and fail to incorporate unique carbohydrates presented on HIV virions required for the binding of several major families of broadly neutralizing antibodies (bNAbs). Here we describe the development of a high-yielding CHO cell line expressing rgp120 from a clade C isolate (TZ97008), representative of the predominant circulating HIV subtype in Southern Africa and Southeast Asia. This cell line, produced using robotic selection, expresses high levels (1.2 g/L) of the TZ97008 rgp120 antigen that incorporates oligomannose glycans required for binding to multiple glycan dependent bNAbs. The resulting rgp120 displays a lower degree of net charge and glycoform heterogeneity as compared to rgp120s produced in normal CHO cells. This homogeneity in net charge facilitates purification by filtration and ion exchange chromatography methods, eliminating the need for expensive custom-made lectin, or immunoaffinity columns. The results described herein document the availability of a novel cell line for the large-scale production of clade C gp120 for clinical trials. Finally, the strategy used to produce a TZ97008 gp120 in the MGAT− CHO cell line can be applied to the production of other candidate HIV vaccines.
Collapse
Affiliation(s)
- Rachel C Doran
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States.,Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Bin Yu
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Meredith Wright
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Sara M O'Rourke
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Lu Yin
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Jennie M Richardson
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Gabriel Byrne
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Kathryn A Mesa
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Phillip W Berman
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, United States
| |
Collapse
|
7
|
O’Rourke SM, Byrne G, Tatsuno G, Wright M, Yu B, Mesa KA, Doran RC, Alexander D, Berman PW. Robotic selection for the rapid development of stable CHO cell lines for HIV vaccine production. PLoS One 2018; 13:e0197656. [PMID: 30071025 PMCID: PMC6071959 DOI: 10.1371/journal.pone.0197656] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/12/2018] [Indexed: 01/13/2023] Open
Abstract
The production of envelope glycoproteins (Envs) for use as HIV vaccines is challenging. The yield of Envs expressed in stable Chinese Hamster Ovary (CHO) cell lines is typically 10-100 fold lower than other glycoproteins of pharmaceutical interest. Moreover, Envs produced in CHO cells are typically enriched for sialic acid containing glycans compared to virus associated Envs that possess mainly high-mannose carbohydrates. This difference alters the net charge and biophysical properties of Envs and impacts their antigenic structure. Here we employ a novel robotic cell line selection strategy to address the problems of low expression. Additionally, we employed a novel gene-edited CHO cell line (MGAT1- CHO) to address the problems of high sialic acid content, and poor antigenic structure. We demonstrate that stable cell lines expressing high levels of gp120, potentially suitable for biopharmaceutical production can be created using the MGAT1- CHO cell line. Finally, we describe a MGAT1- CHO cell line expressing A244-rgp120 that exhibits improved binding of three major families of bN-mAbs compared to Envs produced in normal CHO cells. The new strategy described has the potential to eliminate the bottleneck in HIV vaccine development that has limited the field for more than 25 years.
Collapse
Affiliation(s)
- Sara M. O’Rourke
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - Gabriel Byrne
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - Gwen Tatsuno
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - Meredith Wright
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - Bin Yu
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - Kathryn A. Mesa
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - Rachel C. Doran
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - David Alexander
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| | - Phillip W. Berman
- Department of Biomolecular Engineering, The University of California at Santa Cruz, Santa Cruz, California, United States of America
| |
Collapse
|
8
|
Byrne G, O’Rourke SM, Alexander DL, Yu B, Doran RC, Wright M, Chen Q, Azadi P, Berman PW. CRISPR/Cas9 gene editing for the creation of an MGAT1-deficient CHO cell line to control HIV-1 vaccine glycosylation. PLoS Biol 2018; 16:e2005817. [PMID: 30157178 PMCID: PMC6133382 DOI: 10.1371/journal.pbio.2005817] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 09/11/2018] [Accepted: 08/21/2018] [Indexed: 01/21/2023] Open
Abstract
Over the last decade, multiple broadly neutralizing monoclonal antibodies (bN-mAbs) to the HIV-1 envelope protein (Env) gp120 have been described. Many of these recognize epitopes consisting of both amino acid and glycan residues. Moreover, the glycans required for binding of these bN-mAbs are early intermediates in the N-linked glycosylation pathway. This type of glycosylation substantially alters the mass and net charge of Envs compared to molecules with the same amino acid sequence but possessing mature, complex (sialic acid-containing) carbohydrates. Since cell lines suitable for biopharmaceutical production that limit N-linked glycosylation to mannose-5 (Man5) or earlier intermediates are not readily available, the production of vaccine immunogens displaying these glycan-dependent epitopes has been challenging. Here, we report the development of a stable suspension-adapted Chinese hamster ovary (CHO) cell line that limits glycosylation to Man5 and earlier intermediates. This cell line was created using the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) gene editing system and contains a mutation that inactivates the gene encoding Mannosyl (Alpha-1,3-)-Glycoprotein Beta-1,2-N-Acetylglucosaminyltransferase (MGAT1). Monomeric gp120s produced in the MGAT1- CHO cell line exhibit improved binding to prototypic glycan-dependent bN-mAbs directed to the V1/V2 domain (e.g., PG9) and the V3 stem (e.g., PGT128 and 10-1074) while preserving the structure of the important glycan-independent epitopes (e.g., VRC01). The ability of the MGAT1- CHO cell line to limit glycosylation to early intermediates in the N-linked glycosylation pathway without impairing the doubling time or ability to grow at high cell densities suggests that it will be a useful substrate for the biopharmaceutical production of HIV-1 vaccine immunogens.
Collapse
Affiliation(s)
- Gabriel Byrne
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Sara M. O’Rourke
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - David L. Alexander
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Bin Yu
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Rachel C. Doran
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Meredith Wright
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Qiushi Chen
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States of America
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States of America
| | - Phillip W. Berman
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| |
Collapse
|
9
|
Sequential immunizations with a panel of HIV-1 Env virus-like particles coach immune system to make broadly neutralizing antibodies. Sci Rep 2018; 8:7807. [PMID: 29773829 PMCID: PMC5958130 DOI: 10.1038/s41598-018-25960-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/26/2018] [Indexed: 12/24/2022] Open
Abstract
Broadly neutralizing antibodies (bnAbs) are correlated with passive HIV/SHIV protection and are desirable components of a HIV protective immunity. In the current study, we have designed a sequential-immunization strategy with a panel of envelope glycoprotein (Env)-enriched virus-like particles (VLPs) from various HIV-1 clades (A-E) to elicit bnAbs with high breadth and potency of neutralization in rabbits. We have compared this regimen with repetitive immunizations of individual Env (subtype B) VLPs or a mixture of various Env VLPs. Our results demonstrate that the sequential immunization group of animals induced significantly higher IgG endpoint titers against respective HIV Env (autologous) antigen than other control groups. Animals vaccinated sequentially showed an increase in the antibody endpoint titers and IgG antibody secreting cells (ASCs) against Con-S Env protein. Sequential immunizations with various Env VLPs promoted antibody avidity indices and enhanced bnAb responses against a panel of HIV pseudotyped virions including some of the tier 3 pseudostrains. Sequential immunizations with various VLPs displaying "native-like" HIV-1 Envs elicited bnAb responses with increased breadth and potency of neutralization.
Collapse
|
10
|
Wen Y, Trinh HV, Linton CE, Tani C, Norais N, Martinez-Guzman D, Ramesh P, Sun Y, Situ F, Karaca-Griffin S, Hamlin C, Onkar S, Tian S, Hilt S, Malyala P, Lodaya R, Li N, Otten G, Palladino G, Friedrich K, Aggarwal Y, LaBranche C, Duffy R, Shen X, Tomaras GD, Montefiori DC, Fulp W, Gottardo R, Burke B, Ulmer JB, Zolla-Pazner S, Liao HX, Haynes BF, Michael NL, Kim JH, Rao M, O’Connell RJ, Carfi A, Barnett SW. Generation and characterization of a bivalent protein boost for future clinical trials: HIV-1 subtypes CR01_AE and B gp120 antigens with a potent adjuvant. PLoS One 2018; 13:e0194266. [PMID: 29698406 PMCID: PMC5919662 DOI: 10.1371/journal.pone.0194266] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/28/2018] [Indexed: 01/23/2023] Open
Abstract
The RV144 Phase III clinical trial with ALVAC-HIV prime and AIDSVAX B/E subtypes CRF01_AE (A244) and B (MN) gp120 boost vaccine regime in Thailand provided a foundation for the future development of improved vaccine strategies that may afford protection against the human immunodeficiency virus type 1 (HIV-1). Results from this trial showed that immune responses directed against specific regions V1V2 of the viral envelope (Env) glycoprotein gp120 of HIV-1, were inversely correlated to the risk of HIV-1 infection. Due to the low production of gp120 proteins in CHO cells (2–20 mg/L), cleavage sites in V1V2 loops (A244) and V3 loop (MN) causing heterogeneous antigen products, it was an urgent need to generate CHO cells harboring A244 gp120 with high production yields and an additional, homogenous and uncleaved subtype B gp120 protein to replace MN used in RV144 for the future clinical trials. Here we describe the generation of Chinese Hamster Ovary (CHO) cell lines stably expressing vaccine HIV-1 Env antigens for these purposes: one expressing an HIV-1 subtype CRF01_AE A244 Env gp120 protein (A244.AE) and one expressing an HIV-1 subtype B 6240 Env gp120 protein (6240.B) suitable for possible future manufacturing of Phase I clinical trial materials with cell culture expression levels of over 100 mg/L. The antigenic profiles of the molecules were elucidated by comprehensive approaches including analysis with a panel of well-characterized monoclonal antibodies recognizing critical epitopes using Biacore and ELISA, and glycosylation analysis by mass spectrometry, which confirmed previously identified glycosylation sites and revealed unknown sites of O-linked and N-linked glycosylations at non-consensus motifs. Overall, the vaccines given with MF59 adjuvant induced higher and more rapid antibody (Ab) responses as well as higher Ab avidity than groups given with aluminum hydroxide. Also, bivalent proteins (A244.AE and 6240.B) formulated with MF59 elicited distinct V2-specific Abs to the epitope previously shown to correlate with decreased risk of HIV-1 infection in the RV144 trial. All together, these results provide critical information allowing the consideration of these candidate gp120 proteins for future clinical evaluations in combination with a potent adjuvant.
Collapse
Affiliation(s)
- Yingxia Wen
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Hung V. Trinh
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America
- Henry Jackson Foundation for the Advancement of Military Medicine, Silver Spring, MD, United States of America
| | | | | | | | | | - Priyanka Ramesh
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Yide Sun
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Frank Situ
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | | | - Christopher Hamlin
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America
- Henry Jackson Foundation for the Advancement of Military Medicine, Silver Spring, MD, United States of America
| | - Sayali Onkar
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America
- Henry Jackson Foundation for the Advancement of Military Medicine, Silver Spring, MD, United States of America
| | - Sai Tian
- GSK, Rockville, MD, United States of America
| | - Susan Hilt
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Padma Malyala
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Rushit Lodaya
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Ning Li
- GSK, Rockville, MD, United States of America
| | - Gillis Otten
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Giuseppe Palladino
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | | | - Yukti Aggarwal
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Celia LaBranche
- Department of Surgery, Duke University Medical Center, Durham, NC, United States of America
| | - Ryan Duffy
- Duke Human Vaccine Institute, Duke University, Durham, NC, United States of America
| | - Xiaoying Shen
- Duke Human Vaccine Institute, Duke University, Durham, NC, United States of America
| | - Georgia D. Tomaras
- Department of Surgery, Duke University Medical Center, Durham, NC, United States of America
- Duke Human Vaccine Institute, Duke University, Durham, NC, United States of America
| | - David C. Montefiori
- Department of Surgery, Duke University Medical Center, Durham, NC, United States of America
| | - William Fulp
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Raphael Gottardo
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Brian Burke
- Novartis Vaccines and Diagnostics, Cambridge, MA, United States of America
| | - Jeffrey B. Ulmer
- GSK, Rockville, MD, United States of America
- * E-mail: (SWB); (AC); (JBU)
| | - Susan Zolla-Pazner
- Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Hua-Xin Liao
- Duke Human Vaccine Institute, Duke University, Durham, NC, United States of America
- Biomedine Institute, College of Life Science, Jinan University, Guangzhou, China
| | - Barton F. Haynes
- Duke Human Vaccine Institute, Duke University, Durham, NC, United States of America
| | - Nelson L. Michael
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America
| | - Jerome H. Kim
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America
| | - Mangala Rao
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America
| | - Robert J. O’Connell
- US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States of America
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Andrea Carfi
- GSK, Rockville, MD, United States of America
- * E-mail: (SWB); (AC); (JBU)
| | - Susan W. Barnett
- GSK, Rockville, MD, United States of America
- * E-mail: (SWB); (AC); (JBU)
| |
Collapse
|
11
|
Dey AK, Cupo A, Ozorowski G, Sharma VK, Behrens AJ, Go EP, Ketas TJ, Yasmeen A, Klasse PJ, Sayeed E, Desaire H, Crispin M, Wilson IA, Sanders RW, Hassell T, Ward AB, Moore JP. cGMP production and analysis of BG505 SOSIP.664, an extensively glycosylated, trimeric HIV-1 envelope glycoprotein vaccine candidate. Biotechnol Bioeng 2017; 115:885-899. [PMID: 29150937 PMCID: PMC5852640 DOI: 10.1002/bit.26498] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/30/2017] [Accepted: 11/14/2017] [Indexed: 12/30/2022]
Abstract
We describe the properties of BG505 SOSIP.664 HIV‐1 envelope glycoprotein trimers produced under current Good Manufacturing Practice (cGMP) conditions. These proteins are the first of a new generation of native‐like trimers that are the basis for many structure‐guided immunogen development programs aimed at devising how to induce broadly neutralizing antibodies (bNAbs) to HIV‐1 by vaccination. The successful translation of this prototype demonstrates the feasibility of producing similar immunogens on an appropriate scale and of an acceptable quality for Phase I experimental medicine clinical trials. BG505 SOSIP.664 trimers are extensively glycosylated, contain numerous disulfide bonds and require proteolytic cleavage, all properties that pose a substantial challenge to cGMP production. Our strategy involved creating a stable CHO cell line that was adapted to serum‐free culture conditions to produce envelope glycoproteins. The trimers were then purified by chromatographic methods using a 2G12 bNAb affinity column and size‐exclusion chromatography. The chosen procedures allowed any adventitious viruses to be cleared from the final product to the required extent of >12 log10. The final cGMP production run yielded 3.52 g (peptidic mass) of fully purified trimers (Drug Substance) from a 200 L bioreactor, a notable yield for such a complex glycoprotein. The purified trimers were fully native‐like as judged by negative‐stain electron microscopy, and were stable over a multi‐month period at room temperature or below and for at least 1 week at 50°C. Their antigenicity, disulfide bond patterns, and glycan composition were consistent with trimers produced on a research laboratory scale. The methods reported here should pave the way for the cGMP production of other native‐like Env glycoprotein trimers of various designs and genotypes.
Collapse
Affiliation(s)
- Antu K Dey
- International AIDS Vaccine Initiative, New York, New York
| | - Albert Cupo
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York
| | - Gabriel Ozorowski
- Department of Integrative Structural and Computational Biology, International AIDS Vaccine Initiative (IAVI) Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California
| | | | - Anna-Janina Behrens
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford, UK.,Centre for Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Eden P Go
- Department of Chemistry, The University of Kansas, Lawrence, Kansas
| | - Thomas J Ketas
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York
| | - Anila Yasmeen
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York
| | - Per J Klasse
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York
| | - Eddy Sayeed
- International AIDS Vaccine Initiative, New York, New York
| | - Heather Desaire
- Department of Chemistry, The University of Kansas, Lawrence, Kansas
| | - Max Crispin
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford, UK
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, International AIDS Vaccine Initiative (IAVI) Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California
| | - Rogier W Sanders
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York.,Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Thomas Hassell
- International AIDS Vaccine Initiative, New York, New York
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, International AIDS Vaccine Initiative (IAVI) Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California
| | - John P Moore
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York
| |
Collapse
|
12
|
Behrens AJ, Struwe WB, Crispin M. Glycosylation profiling to evaluate glycoprotein immunogens against HIV-1. Expert Rev Proteomics 2017; 14:881-890. [PMID: 28870097 DOI: 10.1080/14789450.2017.1376658] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Much of the efforts to develop a vaccine against the human immunodeficiency virus (HIV) have focused on the design of recombinant mimics of the viral attachment glycoprotein (Env). The leading immunogens exhibit native-like antigenic properties and are being investigated for their ability to induce broadly neutralizing antibodies (bNAbs). Understanding the relative abundance of glycans at particular glycosylation sites on these immunogens is important as most bNAbs have evolved to recognize or evade the dense coat of glycans that masks much of the protein surface. Understanding the glycan structures on candidate immunogens enables triaging between native-like conformations and immunogens lacking key structural features as steric constraints limit glycan processing. The sensitivity of the processing state of a particular glycan to its structural environment has led to the need for quantitative glycan profiling and site-specific analysis to probe the structural integrity of immunogens. Areas covered: We review analytical methodologies for HIV immunogen evaluation and discuss how these studies have led to a greater understanding of the structural constraints that control the glycosylation state of the HIV attachment and fusion spike. Expert commentary: Total composition and site-specific glycosylation profiling are emerging as standard methods in the evaluation of Env-based immunogen candidates.
Collapse
Affiliation(s)
- Anna-Janina Behrens
- a Oxford Glycobiology Institute, Department of Biochemistry , University of Oxford , Oxford , UK
| | - Weston B Struwe
- a Oxford Glycobiology Institute, Department of Biochemistry , University of Oxford , Oxford , UK
| | - Max Crispin
- a Oxford Glycobiology Institute, Department of Biochemistry , University of Oxford , Oxford , UK.,b Department of Immunology and Microbial Science , The Scripps Research Institute , La Jolla , CA , USA.,c Centre for Biological Sciences and Institute for Life Sciences , University of Southampton , Southampton SO17 1BJ , UK
| |
Collapse
|
13
|
Panels of HIV-1 Subtype C Env Reference Strains for Standardized Neutralization Assessments. J Virol 2017; 91:JVI.00991-17. [PMID: 28747500 PMCID: PMC5599761 DOI: 10.1128/jvi.00991-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 07/19/2017] [Indexed: 12/18/2022] Open
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 viruses representing diverse neutralization sensitivity patterns, given that we do not a priori know 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. IMPORTANCE 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. Use of standard virus panels can facilitate comparison of results across studies and sites.
Collapse
|