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He Y, Zhong L, Yan H, Virata ML, Deng L, Mishra AK, Struble E, Scott D, Zhang P. In vitro enhancement of Zika virus infection by preexisting West Nile virus antibodies in human plasma-derived immunoglobulins revealed after P2 binding site-specific enrichment. Microbiol Spectr 2024; 12:e0075824. [PMID: 38687079 PMCID: PMC11237622 DOI: 10.1128/spectrum.00758-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 04/14/2024] [Indexed: 05/02/2024] Open
Abstract
Human immunoglobulin preparations contain a diverse range of polyclonal antibodies that reflect past immune responses against pathogens encountered by the blood donor population. In this study, we examined a panel of intravenous immunoglobulins (IGIVs) manufactured over the past two decades (1998-2020) for their capacity to neutralize or enhance Zika virus (ZIKV) infection in vitro. These IGIVs were selected specifically based on their production dates in relation to the occurrences of two flavivirus outbreaks in the U.S.: the West Nile virus (WNV) outbreak in 1999 and the ZIKV outbreak in 2015. As demonstrated by enzyme-linked immunosorbent assay (ELISA) experiments, IGIVs made before the ZIKV outbreak already harbored antibodies that bind to various peptides across the envelope protein of ZIKV because of the WNV outbreak. Using phage display, the most dominant binding site was mapped precisely to the P2 peptide between residues 211 and 230 within domain II, where BF1176-56, an anti-ZIKV monoclonal antibody, also binds. When tested in permissive Vero E6 cells for ZIKV neutralization, the IGIVs, even after undergoing rigorous enrichment for P2 binding specificity, failed, as did BF1176-56. Meanwhile, BF1176-56 enhanced ZIKV infection in both FcγRII-expressing K562 cells and human peripheral blood mononuclear cells. However, for enhancement by the IGIVs to be detected in these cells, a substantial increase in their P2 binding specificity was required, thus linking the P2 site with ZIKV enhancement in vitro. Our findings warrant further study of the significance of elevated levels of anti-WNV antibodies in IGIVs, considering that various mechanisms operating in vivo may modulate ZIKV infection outcomes.IMPORTANCEWe investigated the capacity of intravenous immunoglobulins manufactured previously over two decades (1998-2020) to neutralize or enhance Zika virus infection in vitro. West Nile virus antibodies in IGIVs could not neutralize Zika virus initially; however, once the IGIVs were concentrated further, they enhanced its infection. These findings lay the groundwork for exploring how preexisting WNV antibodies in IGIVs could impact Zika infection, both in vitro and in vivo. Our observations are historically significant, since we tested a panel of IGIV lots that were carefully selected based on their production dates which covered two major flavivirus outbreaks in the U.S.: the WNV outbreak in 1999 and the ZIKV outbreak in 2015. These findings will facilitate our understanding of the interplay among closely related viral pathogens, particularly from a historical perspective regarding large blood donor populations. They should remain relevant for future outbreaks of emerging flaviviruses that may potentially affect vulnerable populations.
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Affiliation(s)
- Yong He
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Lilin Zhong
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Hailing Yan
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Maria Luisa Virata
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Lu Deng
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Ashish K. Mishra
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Evi Struble
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Dorothy Scott
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Pei Zhang
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
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Xu Y, Vertrees D, He Y, Momben-Abolfath S, Li X, Brewah YA, Scott DE, Konduru K, Rios M, Struble EB. Nanoluciferase Reporter Zika Viruses as Tools for Assessing Infection Kinetics and Antibody Potency. Viruses 2023; 15:2190. [PMID: 38005868 PMCID: PMC10674863 DOI: 10.3390/v15112190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/16/2023] [Accepted: 10/25/2023] [Indexed: 11/26/2023] Open
Abstract
Zika virus (ZIKV) has become endemic in multiple tropical and subtropical regions and has the potential to become widespread in countries with limited prior exposure to this infection. One of the most concerning sequelae of ZIKV infection is the teratogenic effect on the developing fetus, with the mechanisms of viral spread to and across the placenta remaining largely unknown. Although vaccine trials and prophylactic or therapeutic treatments are being studied, there are no approved treatments or vaccines for ZIKV. Appropriate tests, including potency and in vivo assays to assess the safety and efficacy of these modalities, can greatly aid both the research of the pathophysiology of the infection and the development of anti-ZIKV therapeutics. Building on previous work, we tested reporter ZIKV variants that express nanoluciferase in cell culture and in vivo assays. We found that these variants can propagate in cells shown to be susceptible to the widely used clinical isolate PRVABC59, including Vero and human placenta cell lines. When used in neutralization assays with bioluminescence as readout, these variants gave rise to neutralization curves similar to those produced by PRVABC59, while being better suited for performing high-throughput assays. In addition, the engineered reporter variants can be useful research tools when used in other in vitro and in vivo assays, as we illustrated in transcytosis experiments and a pilot study in guinea pigs.
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Affiliation(s)
- Yanqun Xu
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
| | - Devin Vertrees
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
| | - Yong He
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
| | - Sanaz Momben-Abolfath
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
| | - Xiaohong Li
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
| | - Yambasu A. Brewah
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
| | - Dorothy E. Scott
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
| | - Krishnamurthy Konduru
- Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD 20993, USA; (K.K.); (M.R.)
| | - Maria Rios
- Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD 20993, USA; (K.K.); (M.R.)
| | - Evi B. Struble
- Laboratory of Plasma Derivatives, Division of Plasma Protein Therapeutics, Office of Tissues and Advanced Therapies, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA; (Y.X.); (D.V.); (Y.H.); (X.L.); (Y.A.B.); (D.E.S.)
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Conti F, Moratti M, Leonardi L, Catelli A, Bortolamedi E, Filice E, Fetta A, Fabi M, Facchini E, Cantarini ME, Miniaci A, Cordelli DM, Lanari M, Pession A, Zama D. Anti-Inflammatory and Immunomodulatory Effect of High-Dose Immunoglobulins in Children: From Approved Indications to Off-Label Use. Cells 2023; 12:2417. [PMID: 37830631 PMCID: PMC10572613 DOI: 10.3390/cells12192417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/23/2023] [Accepted: 10/05/2023] [Indexed: 10/14/2023] Open
Abstract
BACKGROUND The large-scale utilization of immunoglobulins in patients with inborn errors of immunity (IEIs) since 1952 prompted the discovery of their key role at high doses as immunomodulatory and anti-inflammatory therapy, in the treatment of IEI-related immune dysregulation disorders, according to labelled and off-label indications. Recent years have been dominated by a progressive imbalance between the gradual but constant increase in the use of immunoglobulins and their availability, exacerbated by the SARS-CoV-2 pandemic. OBJECTIVES To provide pragmatic indications for a need-based application of high-dose immunoglobulins in the pediatric context. SOURCES A literature search was performed using PubMed, from inception until 1st August 2023, including the following keywords: anti-inflammatory; children; high dose gammaglobulin; high dose immunoglobulin; immune dysregulation; immunomodulation; immunomodulatory; inflammation; intravenous gammaglobulin; intravenous immunoglobulin; off-label; pediatric; subcutaneous gammaglobulin; subcutaneous immunoglobulin. All article types were considered. IMPLICATIONS In the light of the current imbalance between gammaglobulins' demand and availability, this review advocates the urgency of a more conscious utilization of this medical product, giving indications about benefits, risks, cost-effectiveness, and administration routes of high-dose immunoglobulins in children with hematologic, neurologic, and inflammatory immune dysregulation disorders, prompting further research towards a responsible employment of gammaglobulins and improving the therapeutical decisional process.
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Affiliation(s)
- Francesca Conti
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (F.C.); (A.M.); (A.P.)
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy; (A.F.); (D.M.C.); (M.L.); (D.Z.)
| | - Mattia Moratti
- Specialty School of Paediatrics, University of Bologna, 40138 Bologna, Italy; (A.C.); (E.B.)
| | - Lucia Leonardi
- Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, 00185 Rome, Italy;
| | - Arianna Catelli
- Specialty School of Paediatrics, University of Bologna, 40138 Bologna, Italy; (A.C.); (E.B.)
| | - Elisa Bortolamedi
- Specialty School of Paediatrics, University of Bologna, 40138 Bologna, Italy; (A.C.); (E.B.)
| | - Emanuele Filice
- Department of Pediatrics, Maggiore Hospital, 40133 Bologna, Italy;
| | - Anna Fetta
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy; (A.F.); (D.M.C.); (M.L.); (D.Z.)
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell’Età Pediatrica, 40139 Bologna, Italy
| | - Marianna Fabi
- Paediatric Emergency Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy;
| | - Elena Facchini
- Pediatric Oncology and Hematology Unit “Lalla Seràgnoli”, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (E.F.); (M.E.C.)
| | - Maria Elena Cantarini
- Pediatric Oncology and Hematology Unit “Lalla Seràgnoli”, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (E.F.); (M.E.C.)
| | - Angela Miniaci
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (F.C.); (A.M.); (A.P.)
| | - Duccio Maria Cordelli
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy; (A.F.); (D.M.C.); (M.L.); (D.Z.)
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell’Età Pediatrica, 40139 Bologna, Italy
| | - Marcello Lanari
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy; (A.F.); (D.M.C.); (M.L.); (D.Z.)
- Paediatric Emergency Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy;
| | - Andrea Pession
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy; (F.C.); (A.M.); (A.P.)
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy; (A.F.); (D.M.C.); (M.L.); (D.Z.)
| | - Daniele Zama
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy; (A.F.); (D.M.C.); (M.L.); (D.Z.)
- Paediatric Emergency Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138 Bologna, Italy;
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Struble EB, Rawson JMO, Stantchev T, Scott D, Shapiro MA. Uses and Challenges of Antiviral Polyclonal and Monoclonal Antibody Therapies. Pharmaceutics 2023; 15:pharmaceutics15051538. [PMID: 37242780 DOI: 10.3390/pharmaceutics15051538] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/04/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Viral diseases represent a major public health concerns and ever-present risks for developing into future pandemics. Antiviral antibody therapeutics, either alone or in combination with other therapies, emerged as valuable preventative and treatment options, including during global emergencies. Here we will discuss polyclonal and monoclonal antiviral antibody therapies, focusing on the unique biochemical and physiological properties that make them well-suited as therapeutic agents. We will describe the methods of antibody characterization and potency assessment throughout development, highlighting similarities and differences between polyclonal and monoclonal products as appropriate. In addition, we will consider the benefits and challenges of antiviral antibodies when used in combination with other antibodies or other types of antiviral therapeutics. Lastly, we will discuss novel approaches to the characterization and development of antiviral antibodies and identify areas that would benefit from additional research.
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Affiliation(s)
- Evi B Struble
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Office of Therapeutic Products, Center for Biologics Evaluation and Research, United States Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Jonathan M O Rawson
- Division of Antivirals, Office of Infectious Diseases, Office of New Drugs, Center for Drug Evaluation and Research, United States Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Tzanko Stantchev
- Division of Biotechnology Review and Research 1, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drug Evaluation and Research, United States Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Dorothy Scott
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Office of Therapeutic Products, Center for Biologics Evaluation and Research, United States Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Marjorie A Shapiro
- Division of Biotechnology Review and Research 1, Office of Biotechnology Products, Office of Pharmaceutical Quality, Center for Drug Evaluation and Research, United States Food and Drug Administration, Silver Spring, MD 20993, USA
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5
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Fox JM, Roy V, Gunn BM, Bolton GR, Fremont DH, Alter G, Diamond MS, Boesch AW. Enhancing the therapeutic activity of hyperimmune IgG against chikungunya virus using FcγRIIIa affinity chromatography. Front Immunol 2023; 14:1153108. [PMID: 37251375 PMCID: PMC10213286 DOI: 10.3389/fimmu.2023.1153108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 04/24/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction Chikungunya virus (CHIKV) is a re-emerging mosquito transmitted alphavirus of global concern. Neutralizing antibodies and antibody Fc-effector functions have been shown to reduce CHIKV disease and infection in animals. However, the ability to improve the therapeutic activity of CHIKV-specific polyclonal IgG by enhancing Fc-effector functions through modulation of IgG subclass and glycoforms remains unknown. Here, we evaluated the protective efficacy of CHIKV-immune IgG enriched for binding to Fc-gamma receptor IIIa (FcγRIIIa) to select for IgG with enhanced Fc effector functions. Methods Total IgG was isolated from CHIKV-immune convalescent donors with and without additional purification by FcγRIIIa affinity chromatography. The enriched IgG was characterized in biophysical and biological assays and assessed for therapeutic efficacy during CHIKV infection in mice. Results FcγRIIIa-column purification enriched for afucosylated IgG glycoforms. In vitro characterization showed the enriched CHIKV-immune IgG had enhanced human FcγRIIIa and mouse FcγRIV affinity and FcγR-mediated effector function without reducing virus neutralization in cellular assays. When administered as post-exposure therapy in mice, CHIKV-immune IgG enriched in afucosylated glycoforms promoted reduction in viral load. Discussion Our study provides evidence that, in mice, increasing Fc engagement of FcγRs on effector cells, by leveraging FcγRIIIa-affinity chromatography, enhanced the antiviral activity of CHIKV-immune IgG and reveals a path to produce more effective therapeutics against these and potentially other emerging viruses.
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Affiliation(s)
- Julie M. Fox
- Department of Medicine, Washington University in St. Louis, St. Louis, MO, United States
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Vicky Roy
- Ragon Institute of Massachusetts General Hospital (MGH), Massachusetts Institute of Technology (MIT), and Harvard University, Cambridge, MA, United States
| | - Bronwyn M. Gunn
- Ragon Institute of Massachusetts General Hospital (MGH), Massachusetts Institute of Technology (MIT), and Harvard University, Cambridge, MA, United States
| | | | - Daved H. Fremont
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO, United States
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO, United States
| | - Galit Alter
- Ragon Institute of Massachusetts General Hospital (MGH), Massachusetts Institute of Technology (MIT), and Harvard University, Cambridge, MA, United States
- Moderna, Inc., Cambridge, MA, United States
| | - Michael S. Diamond
- Department of Medicine, Washington University in St. Louis, St. Louis, MO, United States
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO, United States
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO, United States
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Thompson D, Guenther B, Manayani D, Mendy J, Smith J, Espinosa DA, Harris E, Alexander J, Vang L, Morello CS. Zika virus-like particle vaccine fusion loop mutation increases production yield but fails to protect AG129 mice against Zika virus challenge. PLoS Negl Trop Dis 2022; 16:e0010588. [PMID: 35793354 PMCID: PMC9292115 DOI: 10.1371/journal.pntd.0010588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 07/18/2022] [Accepted: 06/15/2022] [Indexed: 11/26/2022] Open
Abstract
Zika virus (ZIKV) is a mosquito-borne flavivirus with maternal infection associated with preterm birth, congenital malformations, and fetal death, and adult infection associated with Guillain-Barré syndrome. Recent widespread endemic transmission of ZIKV and the potential for future outbreaks necessitate the development of an effective vaccine. We developed a ZIKV vaccine candidate based on virus-like-particles (VLPs) generated following transfection of mammalian HEK293T cells using a plasmid encoding the pre-membrane/membrane (prM/M) and envelope (E) structural protein genes. VLPs were collected from cell culture supernatant and purified by column chromatography with yields of approximately 1-2mg/L. To promote increased particle yields, a single amino acid change of phenylalanine to alanine was made in the E fusion loop at position 108 (F108A) of the lead VLP vaccine candidate. This mutation resulted in a modest 2-fold increase in F108A VLP production with no detectable prM processing by furin to a mature particle, in contrast to the lead candidate (parent). To evaluate immunogenicity and efficacy, AG129 mice were immunized with a dose titration of either the immature F108A or lead VLP (each alum adjuvanted). The resulting VLP-specific binding antibody (Ab) levels were comparable. However, geometric mean neutralizing Ab (nAb) titers using a recombinant ZIKV reporter were significantly lower with F108A immunization compared to lead. After virus challenge, all lead VLP-immunized groups showed a significant 3- to 4-Log10 reduction in mean ZIKV RNAemia levels compared with control mice immunized only with alum, but the RNAemia reduction of 0.5 Log10 for F108A groups was statistically similar to the control. Successful viral control by the lead VLP candidate following challenge supports further vaccine development for this candidate. Notably, nAb titer levels in the lead, but not F108A, VLP-immunized mice inversely correlated with RNAemia. Further evaluation of sera by an in vitro Ab-dependent enhancement assay demonstrated that the F108A VLP-induced immune sera had a significantly higher capacity to promote ZIKV infection in FcγR-expressing cells. These data indicate that a single amino acid change in the fusion loop resulted in increased VLP yields but that the immature F108A particles were significantly diminished in their capacity to induce nAbs and provide protection against ZIKV challenge. Zika virus (ZIKV) is transmitted by mosquitoes and is a serious health threat due to potential epidemic spread. Infection in adults may lead to Guillain-Barré syndrome, a neurological disorder, or may cause harm to a developing fetus resulting in preterm birth, fetal death, or devastating congenital malformations. There are currently no approved vaccines against ZIKV. We previously developed a lead candidate vaccine based on a virus-like particle (VLP) that was generated in tissue culture. This ZIKV shell is devoid of any viral genetic material. In previous studies, this lead VLP candidate generated neutralizing antibodies (nAbs) that recognized wild-type ZIKV and prevented viral replication in both mice and non-human primates. To increase production of the lead VLP candidate and decrease cost-of-goods, we introduced a single amino acid change, phenylalanine to alanine, in the envelope glycoprotein. This change resulted in a modest increase in VLP yield. However, this single amino acid change resulted in reduced induction of nAbs following immunization and no significant reduction of RNAemia following challenge compared to the lead candidate. The results of this study suggest this investigational vaccine candidate is not suitable for further vaccine development and that ZIKV VLP maturation may have an important role in protection.
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Affiliation(s)
- Danielle Thompson
- Emergent BioSolutions Inc., Gaithersburg, Maryland, United States of America
| | - Ben Guenther
- Emergent BioSolutions Inc., Gaithersburg, Maryland, United States of America
| | - Darly Manayani
- PaxVax Inc., San Diego, California, United States of America
| | - Jason Mendy
- Emergent BioSolutions Inc., Gaithersburg, Maryland, United States of America
| | - Jonathan Smith
- PaxVax Inc., San Diego, California, United States of America
| | - Diego A. Espinosa
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Eva Harris
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Jeff Alexander
- Emergent BioSolutions Inc., Gaithersburg, Maryland, United States of America
- PaxVax Inc., San Diego, California, United States of America
| | - Lo Vang
- Emergent BioSolutions Inc., Gaithersburg, Maryland, United States of America
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