Publications by authors named "Hana Golding"

108 Publications

Antibody affinity maturation and plasma IgA associate with clinical outcome in hospitalized COVID-19 patients.

Nat Commun 2021 02 22;12(1):1221. Epub 2021 Feb 22.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD, USA.

Hospitalized COVID-19 patients often present with a large spectrum of clinical symptoms. There is a critical need to better understand the immune responses to SARS-CoV-2 that lead to either resolution or exacerbation of the clinical disease. Here, we examine longitudinal plasma samples from hospitalized COVID-19 patients with differential clinical outcome. We perform immune-repertoire analysis including cytokine, hACE2-receptor inhibition, neutralization titers, antibody epitope repertoire, antibody kinetics, antibody isotype and antibody affinity maturation against the SARS-CoV-2 prefusion spike protein. Fatal cases demonstrate high plasma levels of IL-6, IL-8, TNFα, and MCP-1, and sustained high percentage of IgA-binding antibodies to prefusion spike compared with non-ICU survivors. Disease resolution in non-ICU and ICU patients associates with antibody binding to the receptor binding motif and fusion peptide, and antibody affinity maturation to SARS-CoV-2 prefusion spike protein. Here, we provide insight into the immune parameters associated with clinical disease severity and disease-resolution outcome in hospitalized patients that could inform development of vaccine/therapeutics against COVID-19.
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http://dx.doi.org/10.1038/s41467-021-21463-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900119PMC
February 2021

Production of fever mediator PGE in human monocytes activated with MDP adjuvant is controlled by signaling from MAPK and p300 HAT: Key role of T cell derived factor.

Mol Immunol 2020 12 27;128:139-149. Epub 2020 Oct 27.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), Food and Drug Administration (FDA), Silver Spring, MD 20993, United States. Electronic address:

Fever and inflammatory responses were observed in some subjects in early clinical trials of vaccines adjuvanted with muramyl dipeptide (MDP), a NOD2 agonist. Biosynthesis of Prostaglandin E2 (PGE) that transmits febrile signals to the brain is controlled by an inducible enzyme, Cyclooxygenase 2 (COX-2). MDP alone was not sufficient to induce expression of COX-2 and PGE production in vitro. Conditioned medium prepared from Peripheral Blood Mononuclear Cells (PBMCs)-derived CD3-bead purified human T cells (TCM) dramatically increased COX2 gene transcription, COX-2 protein expression, and PGE production in MDP-treated monocytes. We explored epigenetic changes at the COX2 promoter using Chromatin Immunoprecipitation assay (ChIP). Increase in COX2 transcription correlated with increased recruitment of RNA polymerase II (Pol II) and p300 histone acetyl transferase (HAT) to the COX2 promoter in monocytes activated with MDP and TCM. The role of p300 HAT was confirmed by using C646, an inhibitor of p300, that reduced binding of acetylated H3 and H4 histones at the COX2 promoter, COX2 transcription, and PGE production in monocytes. Binding of p300, Nuclear Factor Kappa B (NF-κB), and Pol II to the COX2 promoter was also sensitive to inhibitors of Mitogen-Activated Protein Kinase (MAPK) pathway and to antibodies against Macrophage-1 (Mac-1) integrin in MDP/TCM-treated monocytes. Importantly, recombinant Glycoprotein Ib alfa (GPIbα), the recently identified factor in TCM, increased binding of NF-κB, p300, and of Pol II to the COX2 promoter and COX2 transcription in MDP-treated monocytes. Our findings suggest that a second signal through Mac-1 and MAPK is triggered by a T cell derived soluble GPIbα protein leading to the assembly of the transcription machinery at the COX2 promoter and production of PGE in human monocytes in response to MDP/NOD2 activation.
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http://dx.doi.org/10.1016/j.molimm.2020.10.008DOI Listing
December 2020

Autoreactivity of Broadly Neutralizing Influenza Human Antibodies to Human Tissues and Human Proteins.

Viruses 2020 10 8;12(10). Epub 2020 Oct 8.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD 20993, USA.

Broadly neutralizing monoclonal antibodies (bNAbs) against conserved domains in the influenza hemagglutinin are in clinical trials. Several next generation influenza vaccines designed to elicit such bNAbs are also in clinical development. One of the common features of the isolated bNAbs is the use of restricted IgV repertoire. More than 80% of stem-targeting bNAbs express IgV1-69, which may indicate genetic constraints on the evolution of such antibodies. In the current study, we evaluated a panel of influenza virus bNAbs in comparison with HIV-1 MAb 4E10 and anti-RSV MAb Palivizumab (approved for human use) for autoreactivity using 30 normal human tissues microarray and human protein (>9000) arrays. We found that several human bNAbs (CR6261, CR9114, and F2603) reacted with human tissues, especially with pituitary gland tissue. Importantly, protein array analysis identified high-affinity interaction of CR6261 with the autoantigen "Enhancer of mRNA decapping 3 homolog" (EDC3), which was not previously described. Moreover, EDC3 competed with hemagglutinin for binding to bNAb CR6261. These autoreactivity findings underscores the need for careful evaluation of such bNAbs for therapeutics and stem-based vaccines against influenza virus.
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http://dx.doi.org/10.3390/v12101140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7600923PMC
October 2020

Antibody signature induced by SARS-CoV-2 spike protein immunogens in rabbits.

Sci Transl Med 2020 07 8;12(550). Epub 2020 Jun 8.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD 20871, USA.

Multiple vaccine candidates against SARS-CoV-2 based on viral spike protein are under development. However, there is limited information on the quality of antibody responses generated with these vaccine modalities. To better understand antibody responses induced by spike protein-based vaccines, we performed a qualitative study by immunizing rabbits with various SARS-CoV-2 spike protein antigens: S ectodomain (S1+S2; amino acids 16 to 1213), which lacks the cytoplasmic and transmembrane domains (CT-TM), the S1 domain (amino acids 16 to 685), the receptor binding domain (RBD) (amino acids 319 to 541), and the S2 domain (amino acids 686 to 1213, lacking the RBD, as control). Resulting antibody quality and function were analyzed by enzyme-linked immunosorbent assay (ELISA), RBD competition assay, surface plasmon resonance (SPR) against different spike proteins in native conformation, and neutralization assays. All three antigens (S1+S2 ectodomain, S1 domain, and RBD), but not S2, generated strong neutralizing antibodies against SARS-CoV-2. Vaccination-induced antibody repertoire was analyzed by SARS-CoV-2 spike genome fragment phage display libraries (SARS-CoV-2 GFPDL), which identified immunodominant epitopes in the S1, S1-RBD, and S2 domains. Furthermore, these analyses demonstrated that the RBD immunogen elicited a higher antibody titer with five-fold higher affinity antibodies to native spike antigens compared with other spike antigens, and antibody affinity correlated strongly with neutralization titers. These findings may help guide rational vaccine design and facilitate development and evaluation of effective therapeutics and vaccines against COVID-19 disease.
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http://dx.doi.org/10.1126/scitranslmed.abc3539DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7286538PMC
July 2020

Antigenic Fingerprinting of Respiratory Syncytial Virus (RSV)-A-Infected Hematopoietic Cell Transplant Recipients Reveals Importance of Mucosal Anti-RSV G Antibodies in Control of RSV Infection in Humans.

J Infect Dis 2020 02;221(4):636-646

Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.

Background: Respiratory syncytial virus (RSV) infection causes significant morbidity in hematopoietic cell transplant (HCT) recipients. However, antibody responses that correlate with recovery from RSV disease are not fully understood.

Methods: In this study, antibody repertoire in paired serum and nasal wash samples from acutely RSV-A-infected HCT recipients who recovered early (<14 days of RSV shedding) were compared with late-recovered patients (≥14 days of shedding) using gene fragment phage display libraries and surface plasmon resonance.

Results: Anti-F serum responses were similar between these 2 groups for antibody repertoires, neutralization titers, anti-F binding antibodies (prefusion and postfusion proteins), antibody avidity, and binding to specific antigenic sites. In contrast, nasal washes from early-recovered individuals demonstrated higher binding to F peptide containing p27. While the serum RSV G antibody repertoires in the 2 groups were similar, the strongest difference between early-recovered and late-recovered patients was observed in the titers of nasal wash antibodies, especially binding to the central conserved domain. Most importantly, a significantly higher antibody affinity to RSV G was observed in nasal washes from early-recovered individuals compared with late-recovered HCT recipients.

Conclusions: These findings highlight the importance of mucosal antibodies in resolution of RSV-A infection in the upper respiratory tract.
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http://dx.doi.org/10.1093/infdis/jiz608DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7530544PMC
February 2020

T cell-derived soluble glycoprotein GPIbα mediates PGE production in human monocytes activated with the vaccine adjuvant MDP.

Sci Signal 2019 10 8;12(602). Epub 2019 Oct 8.

Division of Viral Products, Food and Drug Administration, Silver Spring, MD 20993, USA.

Vaccine adjuvants containing analogs of microbial products activate pattern recognition receptors (PRRs) on antigen-presenting cells, including monocytes and macrophages, which can cause prostaglandin E (PGE) release and consequently undesired inflammatory responses and fever in vaccine recipients. Here, we studied the mechanism of PGE production by human monocytes activated with muramyl dipeptide (MDP) adjuvant, which activates cytosolic nucleotide-binding oligomerization domain 2 (NOD2). In rabbits, administration of MDP elicited an early increase in PGE followed by fever. In human monocytes, MDP alone did not induce PGE production. However, high amounts of PGE and the proinflammatory cytokines IL-1β and IL-6 were secreted by monocytes activated with MDP in the presence of conditioned medium obtained from CD3 bead-isolated T cells (Tc CM) but not from those isolated without CD3 beads. Mass spectrometry and immunoblotting revealed that the costimulatory factor in Tc CM was glycoprotein Ib α (GPIbα). Antibody-mediated blockade of GPIbα or of its receptor, Mac-1 integrin, inhibited the secretion of PGE, IL-1β, and IL-6 in MDP + Tc CM-activated monocytes, whereas recombinant GPIbα protein increased PGE production by MDP-treated monocytes. In vivo, mRNA abundance was reduced in the liver and spleen of Mac-1 KO mice after administration of MDP compared with that of treated wild-type mice. Our findings suggest that the production of PGE and proinflammatory cytokines by MDP-activated monocytes is mediated by cooperation between two signaling pathways: one delivered by MDP through NOD2 and a second through activation of Mac-1 by T cell-derived GPIbα.
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http://dx.doi.org/10.1126/scisignal.aat6023DOI Listing
October 2019

Antibiotics-Driven Gut Microbiome Perturbation Alters Immunity to Vaccines in Humans.

Cell 2019 09;178(6):1313-1328.e13

Institute for Immunity, Transplantation and Infection, School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Pathology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305, USA. Electronic address:

Emerging evidence indicates a central role for the microbiome in immunity. However, causal evidence in humans is sparse. Here, we administered broad-spectrum antibiotics to healthy adults prior and subsequent to seasonal influenza vaccination. Despite a 10,000-fold reduction in gut bacterial load and long-lasting diminution in bacterial diversity, antibody responses were not significantly affected. However, in a second trial of subjects with low pre-existing antibody titers, there was significant impairment in H1N1-specific neutralization and binding IgG1 and IgA responses. In addition, in both studies antibiotics treatment resulted in (1) enhanced inflammatory signatures (including AP-1/NR4A expression), observed previously in the elderly, and increased dendritic cell activation; (2) divergent metabolic trajectories, with a 1,000-fold reduction in serum secondary bile acids, which was highly correlated with AP-1/NR4A signaling and inflammasome activation. Multi-omics integration revealed significant associations between bacterial species and metabolic phenotypes, highlighting a key role for the microbiome in modulating human immunity.
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http://dx.doi.org/10.1016/j.cell.2019.08.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6750738PMC
September 2019

Repeat vaccination reduces antibody affinity maturation across different influenza vaccine platforms in humans.

Nat Commun 2019 07 26;10(1):3338. Epub 2019 Jul 26.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD, 20993, USA.

Several vaccines are approved in the United States for seasonal influenza vaccination every year. Here we compare the impact of repeat influenza vaccination on hemagglutination inhibition (HI) titers, antibody binding and affinity maturation to individual hemagglutinin (HA) domains, HA1 and HA2, across vaccine platforms. Fold change in HI and antibody binding to HA1 trends higher for H1N1pdm09 and H3N2 but not against B strains in groups vaccinated with FluBlok compared with FluCelvax and Fluzone. Antibody-affinity maturation occurs against HA1 domain of H1N1pdm09, H3N2 and B following vaccination with all vaccine platforms, but not against H1N1pdm09-HA2. Importantly, prior year vaccination of subjects receiving repeat vaccinations demonstrated reduced antibody-affinity maturation to HA1 of all three influenza virus strains irrespective of the vaccine platform. This study identifies an important impact of repeat vaccination on antibody-affinity maturation following vaccination, which may contribute to lower vaccine effectiveness of seasonal influenza vaccines in humans.
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http://dx.doi.org/10.1038/s41467-019-11296-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6659679PMC
July 2019

Antibody-dependent enhancement of influenza disease promoted by increase in hemagglutinin stem flexibility and virus fusion kinetics.

Proc Natl Acad Sci U S A 2019 07 11;116(30):15194-15199. Epub 2019 Jul 11.

Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993;

Several next-generation (universal) influenza vaccines and broadly neutralizing antibodies (bNAbs) are in clinical development. Some of these mediate inhibitions of virus replication at the postentry stage or use Fc-dependent mechanisms. Nonneutralizing antibodies have the potential to mediate enhancement of viral infection or disease. In the current study, two monoclonal antibodies (MAbs) 72/8 and 69/1, enhanced respiratory disease (ERD) in mice following H3N2 virus challenge by demonstrating increased lung pathology and changes in lung cytokine/chemokine levels. MAb 78/2 caused changes in the lung viral loads in a dose-dependent manner. Both MAbs increased HA sensitivity to trypsin cleavage at a higher pH range, suggesting MAb-induced conformational changes. pHrodo-labeled virus particles' entry and residence time in the endocytic compartment were tracked during infection of Madin-Darby canine kidney (MDCK) cells. Both MAbs reduced H3N2 virus residence time in the endocytic pathway, suggesting faster virus fusion kinetics. Structurally, 78/2 and 69/1 Fabs bound the globular head or base of the head domain of influenza hemagglutinin (HA), respectively, and induced destabilization of the HA stem domain. Together, this study describes Mab-induced destabilization of the influenza HA stem domain, faster kinetics of influenza virus fusion, and ERD in vivo. The in vivo animal model and in vitro assays described could augment preclinical safety evaluation of antibodies and next-generation influenza vaccines that generate antibodies which do not block influenza virus-receptor interaction.
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http://dx.doi.org/10.1073/pnas.1821317116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6660725PMC
July 2019

Differential human antibody repertoires following Zika infection and the implications for serodiagnostics and disease outcome.

Nat Commun 2019 04 26;10(1):1943. Epub 2019 Apr 26.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD, 20993, USA.

Zika virus (ZIKV) outbreak in Americas led to extensive efforts to develop vaccines and ZIKV-specific diagnostics. In the current study, we use whole genome phage display library spanning the entire ZIKV genome (ZIKV-GFPDL) for in-depth immune profiling of IgG and IgM antibody repertoires in serum and urine longitudinal samples from individuals acutely infected with ZIKV. We observe a very diverse IgM immune repertoire encompassing the entire ZIKV polyprotein on day 0 in both serum and urine. ZIKV-specific IgG antibodies increase 10-fold between day 0 and day 7 in serum, but not in urine; these are highly focused on prM/E, NS1 and NS2B. Differential antibody affinity maturation is observed against ZIKV structural E protein compared with nonstructural protein NS1. Serum antibody affinity to ZIKV-E protein inversely correlates with ZIKV disease symptoms. Our study provides insight into unlinked evolution of immune response to ZIKV infection and identified unique targets for ZIKV serodiagnostics.
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http://dx.doi.org/10.1038/s41467-019-09914-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6486612PMC
April 2019

Prolonged evolution of the memory B cell response induced by a replicating adenovirus-influenza H5 vaccine.

Sci Immunol 2019 04;4(34)

HIV-Specific Immunity Section of the Laboratory of Immunoregulation, National Institutes of Health (NIH), Bethesda, MD 20892, USA.

Induction of an antibody response capable of recognizing highly diverse strains is a major obstacle to the development of vaccines for viruses such as HIV and influenza. Here, we report the dynamics of B cell expansion and evolution at the single-cell level after vaccination with a replication-competent adenovirus type 4 recombinant virus expressing influenza H5 hemagglutinin. Fluorescent H1 or H5 probes were used to quantitate and isolate peripheral blood B cells and their antigen receptors. We observed increases in H5-specific antibody somatic hypermutation and potency for several months beyond the period of active viral replication that was not detectable at the serum level. Individual broad and potent antibodies could be isolated, including one stem-specific antibody that is part of a new multidonor class. These results demonstrate prolonged evolution of the B cell response for months after vaccination and should be considered in efforts to evaluate or boost vaccine-induced immunity.
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http://dx.doi.org/10.1126/sciimmunol.aau2710DOI Listing
April 2019

Broad Hemagglutinin-Specific Memory B Cell Expansion by Seasonal Influenza Virus Infection Reflects Early-Life Imprinting and Adaptation to the Infecting Virus.

J Virol 2019 04 3;93(8). Epub 2019 Apr 3.

David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA

Memory B cells (MBCs) are key determinants of the B cell response to influenza virus infection and vaccination, but the effect of different forms of influenza antigen exposure on MBC populations has received little attention. We analyzed peripheral blood mononuclear cells and plasma collected following human H3N2 influenza infection to investigate the relationship between hemagglutinin-specific antibody production and changes in the size and character of hemagglutinin-reactive MBC populations. Infection produced increased concentrations of plasma IgG reactive to the H3 head of the infecting virus, to the conserved stalk, and to a broad chronological range of H3s consistent with original antigenic sin responses. H3-reactive IgG MBC expansion after infection included reactivity to head and stalk domains. Notably, expansion of H3 head-reactive MBC populations was particularly broad and reflected original antigenic sin patterns of IgG production. Findings also suggest that early-life H3N2 infection "imprints" for strong H3 stalk-specific MBC expansion. Despite the breadth of MBC expansion, the MBC response included an increase in affinity for the H3 head of the infecting virus. Overall, our findings indicate that H3-reactive MBC expansion following H3N2 infection is consistent with maintenance of response patterns established early in life, but nevertheless includes MBC adaptation to the infecting virus. Rapid and vigorous virus-specific antibody responses to influenza virus infection and vaccination result from activation of preexisting virus-specific memory B cells (MBCs). Understanding the effects of different forms of influenza virus exposure on MBC populations is therefore an important guide to the development of effective immunization strategies. We demonstrate that exposure to the influenza hemagglutinin via natural infection enhances broad protection through expansion of hemagglutinin-reactive MBC populations that recognize head and stalk regions of the molecule. Notably, we show that hemagglutinin-reactive MBC expansion reflects imprinting by early-life infection and that this might apply to stalk-reactive, as well as to head-reactive, MBCs. Our findings provide experimental support for the role of MBCs in maintaining imprinting effects and suggest a mechanism by which imprinting might confer heterosubtypic protection against avian influenza viruses. It will be important to compare our findings to the situation after influenza vaccination.
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http://dx.doi.org/10.1128/JVI.00169-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450111PMC
April 2019

AS03-adjuvanted H5N1 vaccine promotes antibody diversity and affinity maturation, NAI titers, cross-clade H5N1 neutralization, but not H1N1 cross-subtype neutralization.

NPJ Vaccines 2018 1;3:40. Epub 2018 Oct 1.

1Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD 20993 USA.

Immune responses to inactivated vaccines against avian influenza are poor due in part to lack of immune memory. Adjuvants significantly increased virus neutralizing titers. We performed comprehensive analyses of polyclonal antibody responses following FDA-approved adjuvanted H5N1-A/Indonesia vaccine, administered in presence or absence of AS03. Using Whole Genome Fragment Phage Display Libraries, we observed that AS03 induced antibody epitope diversity to viral hemagglutinin (HA) and neuraminidase compared with unadjuvanted vaccine. Furthermore, AS03 promoted significant antibody affinity maturation to properly folded H5-HA1 (but not to HA2) domain, which correlated with neutralization titers against both vaccine and heterologous H5N1 strains. However, no increase in heterosubtypic cross-neutralization of Group1-H1N1 seasonal strains was observed. AS03-H5N1 vaccine also induced higher neuraminidase inhibition antibody titers. This study provides insight into the differential impacts of AS03 adjuvant on H5N1 vaccine-induced antibody responses that may help optimize vaccine platforms for future vaccines with improved protection against seasonal and pandemic influenza strains.
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http://dx.doi.org/10.1038/s41541-018-0076-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6167326PMC
October 2018

Protective antigenic sites in respiratory syncytial virus G attachment protein outside the central conserved and cysteine noose domains.

PLoS Pathog 2018 08 24;14(8):e1007262. Epub 2018 Aug 24.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD, United States of America.

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract disease in infants. Previously, we elucidated the antibody repertoire following primary RSV infection in infants. Whole genome-fragment phage display libraries (GFPDL) expressing linear and conformational epitopes from RSV bound 100-fold more phages within attachment protein (G) following primary RSV infection. The G-reactive epitopes spanned the N- and C-termini of G ectodomain, in addition to the central conserved domain (CCD). In the current study, we examined the contribution of antigenic regions of G outside of the CCD to RSV-specific immunity. We evaluated the immunogenicity, neutralization and protective efficacy of all RSV-G antigenic sites identified following primary RSV infection using recombinant E. coli expressed G ectodomain (REG), CCD-deleted G ectodomain (REG ΔCCD), N- and C-terminal G subdomains, and antigenic site peptides. The REG ΔCCD, N- and C-terminal subdomains and peptides generated antibody titers in rabbits and mice that bound fully glycosylated Recombinant Mammalian expressed G ectodomain (RMG) and intact RSV virion particles but minimal in vitro neutralization titers compared with the intact G ectodomain. Vaccinated mice were challenged intranasally with RSV-A2 Line 19F. Viral replication in nasal cavity and lungs was significantly reduced in vaccinated animals compared to unimmunized controls. Control of viral loads post-RSV challenge correlated with serum antibody binding to the virus particles. In addition, very low Th2/Th1 cytokine ratios were found in the lungs of REG ΔCCD vaccinated mice after challenge. These data demonstrate the presence of multiple protective sites in RSV G protein outside of the CCD that could contribute to the development of a bacterially produced unglycosylated G protein as safe and protective vaccine against RSV disease.
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http://dx.doi.org/10.1371/journal.ppat.1007262DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6126872PMC
August 2018

A Potent Germline-like Human Monoclonal Antibody Targets a pH-Sensitive Epitope on H7N9 Influenza Hemagglutinin.

Cell Host Microbe 2017 Oct 28;22(4):471-483.e5. Epub 2017 Sep 28.

Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China. Electronic address:

The H7N9 influenza virus causes high-mortality disease in humans but no effective therapeutics are available. Here we report a human monoclonal antibody, m826, that binds to H7 hemagglutinin (HA) and protects against H7N9 infection. m826 binds to H7N9 HA with subnanomolar affinity at acidic pH and 10-fold lower affinity at neutral pH. The high-resolution (1.9 Å) crystal structure of m826 complexed with H7N9 HA indicates that m826 binds an epitope that may be fully exposed upon pH-induced conformational changes in HA. m826 fully protects mice against lethal challenge with H7N9 virus through mechanisms likely involving antibody-dependent cell-mediated cytotoxicity. Interestingly, immunogenetic analysis indicates that m826 is a germline antibody, and m826-like sequences can be identified in H7N9-infected patients, healthy adults, and newborn babies. These m826 properties offer a template for H7N9 vaccine immunogens, a promising candidate therapeutic, and a tool for exploring mechanisms of virus infection inhibition by antibodies.
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http://dx.doi.org/10.1016/j.chom.2017.08.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6290738PMC
October 2017

Impaired B cell immunity in acute myeloid leukemia patients after chemotherapy.

J Transl Med 2017 07 10;15(1):155. Epub 2017 Jul 10.

Myeloid Malignancies Section, Hematology Branch, National Heart, Lung and Blood Institute, National Institutes of Health, 10 Center Drive Room 10CRC 5-5216, Bethesda, MD, 20814-1476, USA.

Background: Changes in adaptive immune cells after chemotherapy in adult acute myeloid leukemia (AML) may have implications for the success of immunotherapy. This study was designed to determine the functional capacity of the immune system in adult patients with AML who have completed chemotherapy and are potential candidates for immunotherapy.

Methods: We used the response to seasonal influenza vaccination as a surrogate for the robustness of the immune system in 10 AML patients in a complete remission post-chemotherapy and performed genetic, phenotypic, and functional characterization of adaptive immune cell subsets.

Results: Only 2 patients generated protective titers in response to vaccination, and a majority of patients had abnormal frequencies of transitional and memory B-cells. B-cell receptor sequencing showed a B-cell repertoire with little evidence of somatic hypermutation in most patients. Conversely, frequencies of T-cell populations were similar to those seen in healthy controls, and cytotoxic T-cells demonstrated antigen-specific activity after vaccination. Effector T-cells had increased PD-1 expression in AML patients least removed from chemotherapy.

Conclusion: Our results suggest that while some aspects of cellular immunity recover quickly, humoral immunity is incompletely reconstituted in the year following intensive cytotoxic chemotherapy for AML. The observed B-cell abnormalities may explain the poor response to vaccination often seen in AML patients after chemotherapy. Furthermore, the uncoupled recovery of B-cell and T-cell immunity and increased PD-1 expression shortly after chemotherapy might have implications for the success of several modalities of immunotherapy.
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http://dx.doi.org/10.1186/s12967-017-1252-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5504716PMC
July 2017

Development of an animal model of progressive vaccinia in nu/nu mice and the use of bioluminescence imaging for assessment of the efficacy of monoclonal antibodies against vaccinial B5 and L1 proteins.

Antiviral Res 2017 08 8;144:8-20. Epub 2017 May 8.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), Food and Drug Administration (FDA), Silver Spring, MD, USA.

Bioluminescence imaging (BLI) was used to follow dissemination of recombinant vaccinia virus (VACV) expressing luciferase (IHD-J-Luc) in BALB/c nu/nu mice treated post-challenge with monoclonal antibodies (MAbs) against L1 and B5 VACV proteins in a model of Progressive Vaccinia (PV). Areas Under the flux Curve (AUC) were calculated for viral loads in multiple organs in individual mice. Following scarification with 10 pfu, IHD-J-Luc VACV undergoes fast replication at the injection site and disseminates rapidly to the inguinal lymph nodes followed by spleen, liver, and axillary lymph nodes within 2-3 days and before primary lesions are visible at the site of scarification. Extension of survival in nude mice treated with a combination of anti-B5 and anti-L1 MAbs 24 h post challenge correlated with a significant reduction in viral load at the site of scarification and delayed systemic dissemination. Nude mice reconstituted with 10 T cells prior to challenge with IHD-J-Luc, and treated with MAbs post-challenge, survived infection, cleared the virus from all organs and scarification site, and developed anti-VACV IgG and VACV-specific polyfunctional CD8 T cells that co-expressed the degranulation marker CD107a, and IFNγ and TNFα cytokines. All T cell reconstituted mice survived intranasal re-challenge with IHD-J-Luc (10 pfu) two months after the primary infection. Thus, using BLI to monitor VACV replication in a PV model, we showed that anti-VACV MAbs administered post challenge extended survival of nude mice and protected T cell reconstituted nude mice from lethality by reducing replication at the site of scarification and systemic dissemination of VACV.
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http://dx.doi.org/10.1016/j.antiviral.2017.05.002DOI Listing
August 2017

A systematic review and meta-analysis of cross-reactivity of antibodies induced by oil-in-water emulsion adjuvanted influenza H5N1 virus monovalent vaccines.

Vaccine 2017 05 5;35(24):3162-3170. Epub 2017 May 5.

Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, Food and Drug Administration, United States.

Background: Cross-clade immunogenic stockpiled H5N1 vaccines may decrease the morbidity and transmission of infection during the initial phase of influenza pandemic. Meta-analysis of cross-reactive antibodies induced by oil-in-water emulsion adjuvanted (OWEA) influenza H5N1 virus monovalent vaccines with circulating heterologous H5N1 virus strains, isolated from human infections was performed.

Methods: Literature search of MEDLINE, EMBASE, Web of Knowledge, The Cochrane Library, ClinicalTrials.gov, and International Standard Randomised Controlled Trial Number registry was conducted up through December 1, 2015. Methodologically qualified studies were included for (1) use of two doses of licensed OWEA (AS03 or MF59) egg-derived, inactivated influenza H5N1 virus monovalent vaccine, (2) participant age between 18 and 64years, and (3) evaluation of immunogenicity outcome for one or more subclade. Meta-analysis assessed the cross-reactivity of antibodies elicited by clade 1 adjuvanted vaccine strain against clade 2.1 virus strain (A/Vietnam/1194/2004 vs. A/Indonesia/05/2005); and separately against clade 2.2 virus strain (A/Vietnam/1194/2004 vs. A/turkey/Turkey/1/05); and clade 2.1 adjuvanted vaccine strain against clade 1 virus strain (A/Indonesia/05/2005 vs. A/Vietnam/1194/2004). Quantitative publication bias and influence analysis was conducted to evaluate potential impact of unpublished or new studies on the robustness of meta-analysis.

Results: Of 960 articles, 53 qualified for quality assessment and 15 studies met the inclusion criteria. All assessed clade pairs elicited cross-reactive antibodies (clade 1 against clade 2.1 and 2.2; clade 2.1 against clade 1, 2.2, and 2.3). Heterologous strains of same sub-clade are likely to elicit higher cross-reactive antibodies.

Conclusions: OWEA influenza H5N1 virus monovalent vaccines exhibit broad cross-clade immunogenicity, a desired feature for vaccine stockpiling not yet demonstrated by unadjuvanted vaccines. In case of an impending H5N1 virus pandemic, stockpiled OWEA influenza H5N1 virus monovalent vaccines may allow population priming that could slow down the course of pandemic and could offer additional time needed for development of an effective strain specific vaccine supply.
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http://dx.doi.org/10.1016/j.vaccine.2017.04.029DOI Listing
May 2017

What Is the Predictive Value of Animal Models for Vaccine Efficacy in Humans? The Importance of Bridging Studies and Species-Independent Correlates of Protection.

Cold Spring Harb Perspect Biol 2018 04 2;10(4). Epub 2018 Apr 2.

Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993.

Animal models have played a pivotal role in all stages of vaccine development. Their predictive value for vaccine effectiveness depends on the pathogen, the robustness of the animal challenge model, and the correlates of protection (if known). This article will cover key questions regarding bridging animal studies to efficacy trials in humans. Examples include human papillomavirus (HPV) vaccine in which animal protection after vaccination with heterologous prototype virus-like particles (VLPs) predicted successful efficacy trials in humans, and a recent approval of anthrax vaccine in accordance with the "Animal Rule." The establishment of animal models predictive of vaccine effectiveness in humans has been fraught with difficulties with low success rate to date. Challenges facing the use of animal models for vaccine development against Ebola and HIV will be discussed.
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http://dx.doi.org/10.1101/cshperspect.a028902DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5880166PMC
April 2018

Preclinical evaluation of bacterially produced RSV-G protein vaccine: Strong protection against RSV challenge in cotton rat model.

Sci Rep 2017 02 10;7:42428. Epub 2017 Feb 10.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD, 20903, USA.

In current study, we evaluated the safety and protective efficacy of recombinant unglycosylated RSV G protein ectodomain produced in E. coli (in presence and absence of oil-in-water adjuvant) in a preclinical RSV susceptible cotton rat challenge model compared to formaldehyde inactivated RSV (FI-RSV) and live RSV experimental infection. The adjuvanted G protein vaccine induced robust neutralization antibody responses comparable to those generated by live RSV infection. Importantly, adjuvanted G protein significantly reduced viral loads in both the lungs and nose at early time points following viral challenge. Antibody kinetics determined by Surface Plasmon Resonance showed that adjuvanted G generated 10-fold higher G-binding antibodies compared to non-adjvuanted G vaccine and live RSV infection, which correlated strongly with both neutralization titers and viral load titers in the nose and lungs post-viral challenge. Antibody diversity analysis revealed immunodominant antigenic sites in the N- and C-termini of the RSV-G protein, that were boosted >10-fold by adjuvant and inversely correlated with viral load titers. Enhanced lung pathology was observed only in animals vaccinated with FI-RSV, but not in animals vaccinated with unadjuvanted or adjuvanted RSV-G vaccine after viral challenge. The bacterially produced unglycosylated G protein could be developed as a protective vaccine against RSV disease.
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http://dx.doi.org/10.1038/srep42428DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5301242PMC
February 2017

Preexisting Immunity, Not Frailty Phenotype, Predicts Influenza Postvaccination Titers among Older Veterans.

Clin Vaccine Immunol 2017 Mar 6;24(3). Epub 2017 Mar 6.

Geriatric Research, Education, and Clinical Center, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, USA.

Both preexisting immunity to influenza and age have been shown to be correlates of influenza vaccine responses. Frailty, an indicator of functional impairment in older adults, was also shown in one study to predict lower influenza vaccine responses among nonveterans. In the current study, we aimed to determine the associations between frailty, preexisting immunity, and immune responses to influenza vaccine among older veterans. We studied 117 subjects (age range, 62 to 95 years [median age, 81 years]), divided into three cohorts based on the Fried frailty test, i.e., nonfrail (NF) ( = 23 [median age, 68 years]), prefrail ( = 50 [median age, 80 years]), and frail ( = 44 [median age, 82 years]), during the 2010-2011 and 2011-2012 influenza seasons. Subjects received the seasonal trivalent inactivated influenza vaccine, and baseline and postvaccination samples were obtained. Anti-influenza humoral immunity, as measured by hemagglutination inhibition (HI) and microneutralization assays, was measured for influenza B, A(H1N1)pdm09, and A(H3N2) viruses. Postvaccination titers were not different between frail and NF subjects overall in this older subset of veterans. However, preexisting HI titers were strongly correlated with postvaccination titers among all functional status groups. When microneutralization titers were compared, the association between preexisting immunity and vaccine responses varied by frailty status, with the strongest correlation being observed for the NF group. In conclusion, preexisting immunity rather than frailty appeared to predict postvaccination titers in this older veteran cohort.
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http://dx.doi.org/10.1128/CVI.00498-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5339642PMC
March 2017

Development of bioluminescence imaging of respiratory syncytial virus (RSV) in virus-infected live mice and its use for evaluation of therapeutics and vaccines.

Vaccine 2017 01 15;35(4):694-702. Epub 2016 Dec 15.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD 20993, USA. Electronic address:

Respiratory Syncytial virus (RSV) is one of the leading causes of pneumonia among infants with no human vaccine or efficient curative treatments. Efforts are underway to develop new RSV vaccines and therapeutics. There is a dire need for animal models for preclinical evaluation and selection of products against RSV. Herein, we developed a whole body bioluminescence imaging to follow replication of RSV A2 virus strain expressing firefly luciferase (RSVA2-line19-FFL) in live BALB/c mice that can be used as an extremely sensitive readout for studying effects of antiviral and vaccines in living mice. Strong bioluminescence signal was detected in the nasal cavity and in the lungs following intranasal infection of mice with RSVA2-line19-FFL. The kinetics of viral replication in lungs quantified by daily live imaging strongly correlated with viral titers measured by ex-vivo plaque assay and by assessing viral RNA by qRT-PCR. Vaccination of mice with a pre-fusion F protein elicited high neutralizing antibody titers conferring strong protective immunity against virus replication in the nasal cavity and lungs. In contrast, post-challenge treatment of mice with the monoclonal antibody Palivizumab two days after infection reduced viral replication in the nasal cavity at day 4, but only modestly reduced virus loads in the lungs by day 5. In contrast to RSV bioluminescence, plaque assay did not detect viral titers in lungs on day 5 in Palivizumab-treated animals. This difference between viral loads measured by the two assays was found to be due to coating of virions with the Palivizumab that blocked infection of target cells in vitro and shows importance of live imaging in evaluation of RSV therapeutics. This recombinant RSV based live imaging animal model is convenient and valuable tool that can be used to study host dissemination of RSV and evaluation of antiviral compounds and vaccines against RSV.
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http://dx.doi.org/10.1016/j.vaccine.2016.11.044DOI Listing
January 2017

Antigenic Fingerprinting of Antibody Response in Humans following Exposure to Highly Pathogenic H7N7 Avian Influenza Virus: Evidence for Anti-PA-X Antibodies.

J Virol 2016 10 29;90(20):9383-93. Epub 2016 Sep 29.

Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.

Unlabelled: Infections with H7 highly pathogenic avian influenza (HPAI) viruses remain a major public health concern. Adaptation of low-pathogenic H7N7 to highly pathogenic H7N7 in Europe in 2015 raised further alarm for a potential pandemic. An in-depth understanding of antibody responses to HPAI H7 virus following infection in humans could provide important insight into virus gene expression as well as define key protective and serodiagnostic targets. Here we used whole-genome gene fragment phage display libraries (GFPDLs) expressing peptides of 15 to 350 amino acids across the complete genome of the HPAI H7N7 A/Netherlands/33/03 virus. The hemagglutinin (HA) antibody epitope repertoires of 15 H7N7-exposed humans identified clear differences between individuals with no hemagglutination inhibition (HI) titers (<1:10) and those with HI titers of >1:40. Several potentially protective H7N7 epitopes close to the HA receptor binding domain (RBD) and neuraminidase (NA) catalytic site were identified. Surface plasmon resonance (SPR) analysis identified a strong correlation between HA1 (but not HA2) binding antibodies and H7N7 HI titers. A proportion of HA1 binding in plasma was contributed by IgA antibodies. Antibodies against the N7 neuraminidase were less frequent but targeted sites close to the sialic acid binding site. Importantly, we identified strong antibody reactivity against PA-X, a putative virulence factor, in most H7N7-exposed individuals, providing the first evidence for in vivo expression of PA-X and its recognition by the immune system during human influenza A virus infection. This knowledge can help inform the development and selection of the most effective countermeasures for prophylactic as well as therapeutic treatments of HPAI H7N7 avian influenza virus.

Importance: An outbreak of pathogenic H7N7 virus occurred in poultry farms in The Netherlands in 2003. Severe outcome included conjunctivitis, influenza-like illness, and one lethal infection. In this study, we investigated convalescent-phase sera from H7N7-exposed individuals by using a whole-genome phage display library (H7N7-GFPDL) to explore the complete repertoire of post-H7N7-exposure antibodies. PA-X is a recently identified influenza virus virulence protein generated by ribosomal frameshifting in segment 3 of influenza virus coding for PA. However, PA-X expression during influenza virus infection in humans is unknown. We identified strong antibody reactivity against PA-X in most H7N7-exposed individuals (but not in unexposed adults), providing the first evidence for in vivo expression of PA-X and its recognition by the immune system during human infection with pathogenic H7N7 avian influenza virus.
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http://dx.doi.org/10.1128/JVI.01408-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5044853PMC
October 2016

ICOS(+)PD-1(+)CXCR3(+) T follicular helper cells contribute to the generation of high-avidity antibodies following influenza vaccination.

Sci Rep 2016 05 27;6:26494. Epub 2016 May 27.

Baylor Institute for Immunology Research, Baylor Research Institute, Dallas, TX, 75204, USA.

The immune mechanism leading to the generation of protective antibody responses following influenza trivalent inactivated vaccine (TIV) vaccinations remains largely uncharacterized. We recently reported that TIV vaccination induced a transient increase of circulating ICOS(+)PD-1(+)CXCR3(+) T follicular helper (cTfh) cells in blood, which positively correlated with the induction of protective antibody responses measured at day 28. However, whether and how these T cells directly contribute to antibody response remains unclear. In this study, we analyzed the changes after TIV vaccination in the amount and the avidity of the polyclonal antibodies specific for the HA1 subunit of the pandemic H1N1 virus, and analyzed the correlation with the increase of ICOS(+)PD-1(+)CXCR3(+) cTfh cells. We found that both the amount and the avidity of specific antibodies rapidly increased during the first 7 days after TIV. Importantly, the increase of ICOS(+)PD-1(+)CXCR3(+) cTfh cells strongly correlated with the increase in the avidity of antibodies, particularly in subjects who did not have high affinity antibodies at baseline. We propose that ICOS(+)PD-1(+)CXCR3(+) Tfh cells directly contribute to the generation of high-avidity antibodies after TIV vaccinations by selectively interacting with high affinity B cells at extrafollicular sites.
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http://dx.doi.org/10.1038/srep26494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4882544PMC
May 2016

Production of Potent Fully Human Polyclonal Antibodies against Ebola Zaire Virus in Transchromosomal Cattle.

Sci Rep 2016 04 25;6:24897. Epub 2016 Apr 25.

SAB Biotherapeutics, Sioux Falls, South Dakota, United States of America.

Polyclonal antibodies, derived from humans or hyperimmunized animals, have been used prophylactically or therapeutically as countermeasures for a variety of infectious diseases. SAB Biotherapeutics has successfully developed a transchromosomic (Tc) bovine platform technology that can produce fully human immunoglobulins rapidly, and in substantial quantities, against a variety of disease targets. In this study, two Tc bovines expressing high levels of fully human IgG were hyperimmunized with a recombinant glycoprotein (GP) vaccine consisting of the 2014 Ebola virus (EBOV) Makona isolate. Serum collected from these hyperimmunized Tc bovines contained high titers of human IgG against EBOV GP as determined by GP specific ELISA, surface plasmon resonance (SPR), and virus neutralization assays. Fully human polyclonal antibodies against EBOV were purified and evaluated in a mouse challenge model using mouse adapted Ebola virus (maEBOV). Intraperitoneal administration of the purified anti-EBOV IgG (100 mg/kg) to BALB/c mice one day after lethal challenge with maEBOV resulted in 90% protection; whereas 100% of the control animals succumbed. The results show that hyperimmunization of Tc bovines with EBOV GP can elicit protective and potent neutralizing fully human IgG antibodies rapidly and in commercially viable quantities.
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http://dx.doi.org/10.1038/srep24897DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4842964PMC
April 2016

Antigenic Fingerprinting following Primary RSV Infection in Young Children Identifies Novel Antigenic Sites and Reveals Unlinked Evolution of Human Antibody Repertoires to Fusion and Attachment Glycoproteins.

PLoS Pathog 2016 04 21;12(4):e1005554. Epub 2016 Apr 21.

Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, Maryland, United States of America.

Respiratory Syncytial Virus (RSV) is the major cause of pneumonia among infants. Here we elucidated the antibody repertoire following primary RSV infection and traced its evolution through adolescence and adulthood. Whole genome-fragment phage display libraries (GFPDL) expressing linear and conformational epitopes in the RSV fusion protein (F) and attachment protein (G) were used for unbiased epitope profiling of infant sera prior to and following RSV infection. F-GFPDL analyses demonstrated modest changes in the anti-F epitope repertoires post-RSV infection, while G-GFPDL analyses revealed 100-fold increase in number of bound phages. The G-reactive epitopes spanned the N- and C-terminus of the G ectodomain, along with increased reactivity to the central conserved domain (CCD). Panels of F and G antigenic sites were synthesized to evaluate sera from young children (<2 yr), adolescents (14-18 yr) and adults (30-45 yr) in SPR real-time kinetics assays. A steady increase in RSV-F epitope repertoires from young children to adults was observed using peptides and F proteins. Importantly, several novel epitopes were identified in pre-fusion F and an immunodominant epitope in the F-p27. In all age groups, antibody binding to pre-fusion F was 2-3 folds higher than to post-fusion form. For RSV-G, antibody responses were high following early RSV infection in children, but declined significantly in adults, using either G proteins or peptides. This study identified unlinked evolution of anti-F and anti G responses and supportive evidence for immune pressure driven evolution of RSV-G. These findings could help development of effective countermeasures including vaccines.
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http://dx.doi.org/10.1371/journal.ppat.1005554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4839671PMC
April 2016

Patients with MS under daclizumab therapy mount normal immune responses to influenza vaccination.

Neurol Neuroimmunol Neuroinflamm 2016 Feb 27;3(1):e196. Epub 2016 Jan 27.

Neuroimmunological Diseases Unit, Neuroimmunology Branch (Y.C.L., P.W., A.B., E.R., B.B.) and Clinical Neuroscience Program (T.W.), National Institute of Neurological Diseases and Stroke, NIH, Bethesda, MD; FDA (J.M., L.R.K., H.G.), CBER; and NIH Center for Human Immunology (B.B.), NIH, Bethesda, MD.

Objective: The purpose of this study was to assess the potential immunosuppressive role of daclizumab, a humanized monoclonal antibody against the α chain of the interleukin 2 receptor, in vivo, by comparing immune responses to the 2013 seasonal influenza vaccination between patients with multiple sclerosis (MS) on long-term daclizumab therapy and controls.

Methods: Previously defined subpopulations of adaptive immune cells known to correlate with the immune response to the influenza vaccination were evaluated by 12-color flow cytometry in 23 daclizumab-treated patients with MS and 14 MS or healthy controls before (D0) and 1 day (D1) and 7 days (D7) after administration of the 2013 Afluria vaccine. Neutralizing antibody titers and CD4(+), CD8(+) T cell, B cell, and natural killer cell proliferation to 3 strains of virus contained in the Afluria vaccine were assessed at D0, D7, and 180 days postvaccination.

Results: Daclizumab-treated patients and controls demonstrated comparable, statistically significant expansions of previously defined subpopulations of activated CD8(+) T cells and B cells that characterize the development of effective immune responses to the influenza vaccine, while proliferation of T cells to influenza and control antigens was diminished in the daclizumab cohort. All participants fulfilled FDA criteria for seroconversion or seroprotection in antibody assays.

Conclusion: Despite the mild immunosuppressive effects of daclizumab in vivo demonstrated by an increased incidence of infectious complications in clinical trials, patients with MS under daclizumab therapy mount normal antibody responses to influenza vaccinations.
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http://dx.doi.org/10.1212/NXI.0000000000000196DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4733151PMC
February 2016

A Simple Flow-Cytometric Method Measuring B Cell Surface Immunoglobulin Avidity Enables Characterization of Affinity Maturation to Influenza A Virus.

mBio 2015 Aug 4;6(4):e01156. Epub 2015 Aug 4.

Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA

Unlabelled: Antibody (Ab) affinity maturation enables an individual to maintain immunity to an increasing number of pathogens within the limits of a total Ig production threshold. A better understanding of this process is critical for designing vaccines that generate optimal Ab responses to pathogens. Our study describes a simple flow-cytometric method that enumerates virus-specific germinal center (GC) B cells as well as their AC50, a measure of Ab avidity, defined as the antigen concentration required to detect 50% of specific B cells. Using a model of mouse Ab responses to the influenza A virus hemagglutinin (IAV HA), we obtained data indicating that AC50 decreases with time postinfection in an affinity maturation-dependent process. As proof of principle of the utility of the method, our data clearly show that relative to intranasal IAV infection, intramuscular immunization against inactivated IAV in adjuvant results in a diminished GC HA B cell response, with increased AC50 correlating with an increased serum Ab off-rate. Enabling simultaneous interrogation of both GC HA B cell quantity and quality, this technique should facilitate study of affinity maturation and rational vaccine design.

Importance: Though it was first described 50 years ago, little is known about how antibody affinity maturation contributes to immunity. This question is particularly relevant to developing more effective vaccines for influenza A virus (IAV) and other viruses that are difficult vaccine targets. Limitations in methods for characterizing antigen-specific B cells have impeded progress in characterizing the quality of immune responses to vaccine and natural immunogens. In this work, we describe a simple flow cytometry-based approach that measures both the number and affinity of IAV-binding germinal center B cells specific for the IAV HA, the major target of IAV-neutralizing antibodies. Using this method, we showed that the route and form of immunization significantly impacts the quality and quantity of B cell antibody responses. This method provides a relatively simple yet powerful tool for better understanding the contribution of affinity maturation to viral immunity.
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http://dx.doi.org/10.1128/mBio.01156-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4526714PMC
August 2015

ISCOMATRIX™ adjuvant promotes epitope spreading and antibody affinity maturation of influenza A H7N9 virus like particle vaccine that correlate with virus neutralization in humans.

Vaccine 2015 Jul 17;33(32):3953-62. Epub 2015 Jun 17.

Division of Viral Products, CBER, FDA, Silver Spring, MD 20993, USA. Electronic address:

In a previously reported phase I clinical trial, subjects vaccinated with two doses of an unadjuvanted H7N9 virus like particle (VLP) vaccine responded poorly (15.6% seroconversion rates with 45μg hemagglutinin (HA) dose). In contrast, 80.6% of subjects receiving H7N9 VLP vaccine (5μg HA) with ISCOMATRIX™ adjuvant developed hemagglutination-inhibition (HI) responses. To better understand the role of adjuvant, complete antibody epitope repertoires of post-vaccination sera were investigated using Whole Genome Fragment Phage Display Library (GFPDL). In addition, antibody affinity maturation following vaccination was measured against HA1 and HA2 antigenic domains using real time Surface Plasmon Resonance (SPR) based kinetic assays. Unadjuvanted H7N9-VLP vaccine generated primarily antibodies targeting the C-terminus of the HA1 domain, predicted to be mostly buried on the native HA spikes, while adjuvanted VLP vaccine generated antibodies against large epitopes in the HA1 spanning the receptor binding domain (RBD). SPR analysis using a functional H7-HA1 domain demonstrated that sera from adjuvanted H7N9-VLP vaccine induced higher total binding antibodies and significantly higher antibody affinity maturation to HA1 compared to sera from unadjuvanted vaccine. Total antibody binding and affinity to the HA1 (but not HA2) domain correlated with HI and neutralization titers. This study demonstrates that ISCOMATRIX™ adjuvanted vaccine promotes higher quality antibody immune response against avian influenza in naïve humans.
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http://dx.doi.org/10.1016/j.vaccine.2015.06.047DOI Listing
July 2015

Nonglycosylated G-Protein Vaccine Protects against Homologous and Heterologous Respiratory Syncytial Virus (RSV) Challenge, while Glycosylated G Enhances RSV Lung Pathology and Cytokine Levels.

J Virol 2015 Aug 27;89(16):8193-205. Epub 2015 May 27.

Division of Viral Products, Center for Biologics Evaluation and Research, FDA, Silver Spring, Maryland, USA

Unlabelled: New efforts are under way to develop a vaccine against respiratory syncytial virus (RSV) that will provide protective immunity without the potential for vaccine-associated disease enhancement such as that observed in infants following vaccination with formalin-inactivated RSV vaccine. In addition to the F fusion protein, the G attachment surface protein is a target for neutralizing antibodies and thus represents an important vaccine candidate. However, glycosylated G protein expressed in mammalian cells has been shown to induce pulmonary eosinophilia upon RSV infection in a mouse model. In the current study, we evaluated in parallel the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain (amino acids 67 to 298) expressed in Escherichia coli (REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model. Vaccination with REG generated neutralizing antibodies against RSV A2 in 7/11 BALB/c mice, while RMG did not elicit neutralizing antibodies. Total serum binding antibodies against the recombinant proteins (both REG and RMG) were measured by surface plasmon resonance (SPR) and were found to be >10-fold higher for REG- than for RMG-vaccinated animals. Reduction of lung viral loads to undetectable levels after homologous (RSV-A2) and heterologous (RSV-B1) viral challenge was observed in 7/8 animals vaccinated with REG but not in RMG-vaccinated animals. Furthermore, enhanced lung pathology and elevated Th2 cytokines/chemokines were observed exclusively in animals vaccinated with RMG (but not in those vaccinated with REG or phosphate-buffered saline [PBS]) after homologous or heterologous RSV challenge. This study suggests that bacterially produced unglycosylated G protein could be developed alone or as a component of a protective vaccine against RSV disease.

Importance: New efforts are under way to develop vaccines against RSV that will provide protective immunity without the potential for disease enhancement. The G attachment protein represents an important candidate for inclusion in an effective RSV vaccine. In the current study, we evaluated the safety and protective efficacy of the RSV A2 recombinant unglycosylated G protein ectodomain produced in E. coli (REG) and those of glycosylated G produced in mammalian cells (RMG) in a mouse RSV challenge model (strains A2 and B1). The unglycosylated G generated high protective immunity and no lung pathology, even in animals that lacked anti-RSV neutralizing antibodies prior to RSV challenge. Control of viral loads correlated with antibody binding to the G protein. In contrast, the glycosylated G protein provided poor protection and enhanced lung pathology after RSV challenge. Therefore, bacterially produced unglycosylated G protein holds promise as an economical approach to a protective vaccine against RSV.
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http://dx.doi.org/10.1128/JVI.00133-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4524247PMC
August 2015