scholarly journals Comparison of Immune Responses to Different Versions of VLP Associated Stabilized RSV Pre-Fusion F Protein

Vaccines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 21 ◽  
Author(s):  
Lori Cullen ◽  
Madelyn Schmidt ◽  
Gretel Torres ◽  
Adam Capoferri ◽  
Trudy Morrison
Keyword(s):  
Monoclonal Antibodies ◽  
Respiratory Syncytial Virus ◽  
Immune Responses ◽  
Fusion Protein ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Vaccine Candidates ◽  
F Protein ◽  
Syncytial Virus ◽  
Conformation Stability

Efforts to develop a vaccine for respiratory syncytial virus (RSV) have primarily focused on the RSV fusion protein. The pre-fusion conformation of this protein induces the most potent neutralizing antibodies and is the focus of recent efforts in vaccine development. Following the first identification of mutations in the RSV F protein (DS-Cav1 mutant protein) that stabilized the pre-fusion conformation, other mutant stabilized pre-fusion F proteins have been described. To determine if there are differences in alternate versions of stabilized pre-fusion F proteins, we explored the use, as vaccine candidates, of virus-like particles (VLPs) containing five different pre-fusion F proteins, including the DS-Cav1 protein. The expression of these five pre-F proteins, their assembly into VLPs, their pre-fusion conformation stability in VLPs, their reactivity with anti-F monoclonal antibodies, and their induction of immune responses after the immunization of mice, were characterized, comparing VLPs containing the DS-Cav1 pre-F protein with VLPs containing four alternative pre-fusion F proteins. The concentrations of anti-F IgG induced by each VLP that blocked the binding of prototype monoclonal antibodies using two different soluble pre-fusion F proteins as targets were measured. Our results indicate that both the conformation and immunogenicity of alternative VLP associated stabilized pre-fusion RSV F proteins are different from those of DS-Cav1 VLPs.

scholarly journals Removal of the N-Glycosylation Sequon at Position N116 Located in p27 of the Respiratory Syncytial Virus Fusion Protein Elicits Enhanced Antibody Responses after DNA Immunization

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 426 ◽  
Author(s):  
Annelies Leemans ◽  
Marlies Boeren ◽  
Winke Van der Gucht ◽  
Isabel Pintelon ◽  
Kenny Roose ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Natural Infection ◽  
Antibody Responses ◽  
F Protein ◽  
Glycosylation Sites ◽  
Potential Vaccine ◽  
Syncytial Virus ◽  
Tract Infections

Prevention of severe lower respiratory tract infections in infants caused by the human respiratory syncytial virus (hRSV) remains a major public health priority. Currently, the major focus of vaccine development relies on the RSV fusion (F) protein since it is the main target protein for neutralizing antibodies induced by natural infection. The protein conserves 5 N-glycosylation sites, two of which are located in the F2 subunit (N27 and N70), one in the F1 subunit (N500) and two in the p27 peptide (N116 and N126). To study the influence of the loss of one or more N-glycosylation sites on RSV F immunogenicity, BALB/c mice were immunized with plasmids encoding RSV F glycomutants. In comparison with F WT DNA immunized mice, higher neutralizing titres were observed following immunization with F N116Q. Moreover, RSV A2-K-line19F challenge of mice that had been immunized with mutant F N116Q DNA was associated with lower RSV RNA levels compared with those in challenged WT F DNA immunized animals. Since p27 is assumed to be post-translationally released after cleavage and thus not present on the mature RSV F protein, it remains to be elucidated how deletion of this glycan can contribute to enhanced antibody responses and protection upon challenge. These findings provide new insights to improve the immunogenicity of RSV F in potential vaccine candidates.

scholarly journals Formulation of bovine respiratory syncytial virus fusion protein with CpG oligodeoxynucleotide, cationic host defence peptide and polyphosphazene enhances humoral and cellular responses and induces a protective type 1 immune response in mice

2009 ◽  
Vol 90 (8) ◽  
pp. 1892-1905 ◽  
Author(s):  
J. Kovacs-Nolan ◽  
J. W. Mapletoft ◽  
Z. Lawman ◽  
L. A. Babiuk ◽  
S. van Drunen Littel-van den Hurk
Keyword(s):  
Immune Response ◽  
Respiratory Syncytial Virus ◽  
Immune Responses ◽  
Fusion Protein ◽  
Vaccine Development ◽  
Host Defence ◽  
Cpg Odn ◽  
Cpg Oligodeoxynucleotides ◽  
Cpg Oligodeoxynucleotide ◽  
Syncytial Virus

Respiratory syncytial virus (RSV) is the leading cause of serious respiratory tract disease in children and calves; however, RSV vaccine development has been slow due to early observations that formalin-inactivated vaccines induced Th2-type immune responses and led to disease enhancement upon subsequent exposure. Hence, there is a need for novel adjuvants that will promote a protective Th1-type or balanced immune response against RSV. CpG oligodeoxynucleotides (ODNs), indolicidin, and polyphosphazene were examined for their ability to enhance antigen-specific immune responses and influence the Th-bias when co-formulated with a recombinant truncated bovine RSV (BRSV) fusion protein (ΔF). Mice immunized with ΔF co-formulated with CpG ODN, indolicidin, and polyphosphazene (ΔF/CpG/indol/PP) developed higher levels of ΔF-specific serum IgG, IgG1 and IgG2a antibodies when compared with ΔF alone, and displayed an increase in the frequency of gamma interferon-secreting cells and decreased interleukin (IL)-5 production by in vitro restimulated splenocytes, characteristic of a Th1 immune response. These results were observed in both C57BL/6 and BALB/c strains of mice. When evaluated in a BRSV challenge model, mice immunized with ΔF/CpG/indol/PP developed significantly higher levels of BRSV-neutralizing serum antibodies than mice immunized with the ΔF protein alone, and displayed significantly less pulmonary IL-4, IL-5, IL-13 and eotaxin and reduced eosinophilia after challenge. These results suggest that co-formulation of ΔF with CpG ODN, host defence peptide and polyphosphazene may result in a safe and effective vaccine for the prevention of BRSV and may have implications for the development of novel human RSV vaccines.

scholarly journals Structural basis for nonneutralizing antibody competition at antigenic site II of the respiratory syncytial virus fusion protein

2016 ◽  
Vol 113 (44) ◽  
pp. E6849-E6858 ◽  
Author(s):  
Jarrod J. Mousa ◽  
Marion F. Sauer ◽  
Alexander M. Sevy ◽  
Jessica A. Finn ◽  
John T. Bates ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Severe Disease ◽  
Antigenic Site ◽  
Structural Basis ◽  
Human Antibody ◽  
Human Mabs ◽  
F Protein ◽  
Syncytial Virus

Palivizumab was the first antiviral monoclonal antibody (mAb) approved for therapeutic use in humans, and remains a prophylactic treatment for infants at risk for severe disease because of respiratory syncytial virus (RSV). Palivizumab is an engineered humanized version of a murine mAb targeting antigenic site II of the RSV fusion (F) protein, a key target in vaccine development. There are limited reported naturally occurring human mAbs to site II; therefore, the structural basis for human antibody recognition of this major antigenic site is poorly understood. Here, we describe a nonneutralizing class of site II-specific mAbs that competed for binding with palivizumab to postfusion RSV F protein. We also describe two classes of site II-specific neutralizing mAbs, one of which escaped competition with nonneutralizing mAbs. An X-ray crystal structure of the neutralizing mAb 14N4 in complex with F protein showed that the binding angle at which human neutralizing mAbs interact with antigenic site II determines whether or not nonneutralizing antibodies compete with their binding. Fine-mapping studies determined that nonneutralizing mAbs that interfere with binding of neutralizing mAbs recognize site II with a pose that facilitates binding to an epitope containing F surface residues on a neighboring protomer. Neutralizing antibodies, like motavizumab and a new mAb designated 3J20 that escape interference by the inhibiting mAbs, avoid such contact by binding at an angle that is shifted away from the nonneutralizing site. Furthermore, binding to rationally and computationally designed site II helix–loop–helix epitope-scaffold vaccines distinguished neutralizing from nonneutralizing site II antibodies.

scholarly journals Characterization of Pre-F-GCN4t, a Modified Human Respiratory Syncytial Virus Fusion Protein Stabilized in a Noncleaved Prefusion Conformation

2017 ◽  
Vol 91 (13) ◽  
Author(s):  
Normand Blais ◽  
Martin Gagné ◽  
Yoshitomo Hamuro ◽  
Patrick Rheault ◽  
Martine Boyer ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Antibody Response ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Human Respiratory Syncytial Virus ◽  
Vaccine Antigen ◽  
Significant Advance ◽  
F Protein ◽  
Syncytial Virus

ABSTRACT The human respiratory syncytial virus (hRSV) fusion (F) protein is considered a major target of the neutralizing antibody response to hRSV. This glycoprotein undergoes a major structural shift from the prefusion (pre-F) to the postfusion (post-F) state at the time of virus-host cell membrane fusion. Recent evidences suggest that the pre-F state is a superior target for neutralizing antibodies compared to the post-F state. Therefore, for vaccine purposes, we have designed and characterized a recombinant hRSV F protein, called Pre-F-GCN4t, stabilized in a pre-F conformation. To show that Pre-F-GCN4t does not switch to a post-F conformation, it was compared with a recombinant post-F molecule, called Post-F-XC. Pre-F-GCN4t was glycosylated and trimeric and displayed a conformational stability different from that of Post-F-XC, as shown by chemical denaturation. Electron microscopy analysis suggested that Pre-F-GCN4t adopts a lollipop-like structure. In contrast, Post-F-XC had a typical elongated conical shape. Hydrogen/deuterium exchange mass spectrometry demonstrated that the two molecules had common rigid folding core and dynamic regions and provided structural insight for their biophysical and biochemical properties and reactivity. Pre-F-GCN4t was shown to deplete hRSV-neutralizing antibodies from human serum more efficiently than Post-F-XC. Importantly, Pre-F-GCN4t was also shown to bind D25, a highly potent monoclonal antibody specific for the pre-F conformation. In conclusion, this construct presents several pre-F characteristics, does not switch to the post-F conformation, and presents antigenic features required for a protective neutralizing antibody response. Therefore, Pre-F-GCN4t can be considered a promising candidate vaccine antigen. IMPORTANCE Human respiratory syncytial virus (RSV) is a global leading cause of infant mortality and adult morbidity. The development of a safe and efficacious RSV vaccine remains an important goal. The RSV class I fusion (F) glycoprotein is considered one of the most promising vaccine candidates, and recent evidences suggest that the prefusion (pre-F) state is a superior target for neutralizing antibodies. Our study presents the physicochemical characterization of Pre-F-GCN4t, a molecule designed to be stabilized in the pre-F conformation. To confirm its pre-F conformation, Pre-F-GCN4t was analyzed in parallel with Post-F-XC, a molecule in the post-F conformation. Our results show that Pre-F-GCN4t presents characteristics of a stabilized pre-F conformation and support its use as an RSV vaccine antigen. Such an antigen may represent a significant advance in the development of an RSV vaccine.

scholarly journals Simultaneous Administration of Recombinant Measles Viruses Expressing Respiratory Syncytial Virus Fusion (F) and Nucleo (N) Proteins Induced Humoral and Cellular Immune Responses in Cotton Rats

Vaccines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 27 ◽  
Author(s):  
Yoshiaki Yamaji ◽  
Akihito Sawada ◽  
Yosuke Yasui ◽  
Takashi Ito ◽  
Tetsuo Nakayama
Keyword(s):  
Respiratory Syncytial Virus ◽  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Simultaneous Administration ◽  
Cellular Immune Responses ◽  
Immunization Group ◽  
Cotton Rats ◽  
Ifn Γ ◽  
Syncytial Virus ◽  
Cellular Immune

We previously reported that recombinant measles virus expressing the respiratory syncytial virus (RSV) fusion protein (F), MVAIK/RSV/F, induced neutralizing antibodies against RSV, and those expressing RSV-NP (MVAIK/RSV/NP) and M2-1 (MVAIK/RSV/M2-1) induced RSV-specific CD8+/IFN-γ+ cells, but not neutralizing antibodies. In the present study, MVAIK/RSV/F and MVAIK/RSV/NP were simultaneously administered to cotton rats and immune responses and protective effects were compared with MVAIK/RSV/F alone. Sufficient neutralizing antibodies against RSV and RSV-specific CD8+/IFN-γ+ cells were observed after re-immunization with simultaneous administration. After the RSV challenge, CD8+/IFN-γ+ increased in spleen cells obtained from the simultaneous immunization group in response to F and NP peptides. Higher numbers of CD8+/IFN-γ+ and CD4+/IFN-γ+ cells were detected in lung tissues from the simultaneous immunization group after the RSV challenge. No detectable RSV was recovered from lung homogenates in the immunized groups. Mild inflammatory reactions with the thickening of broncho-epithelial cells and the infiltration of inflammatory cells were observed in lung tissues obtained from cotton rats immunized with MVAIK/RSV/F alone after the RSV challenge. No inflammatory responses were observed after the RSV challenge in the simultaneous immunization groups. The present results indicate that combined administration with MVAIK/RSV/F and MVAIK/RSV/NP induces humoral and cellular immune responses and shows effective protection against RSV, suggesting the importance of cellular immunity.

scholarly journals Inferior immunogenicity and efficacy of respiratory syncytial virus fusion protein-based subunit vaccine candidates in aged versus young mice

PLoS ONE ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. e0188708 ◽  
Author(s):  
Corinne Cayatte ◽  
Angie Snell Bennett ◽  
Gaurav Manohar Rajani ◽  
Leigh Hostetler ◽  
Sean K. Maynard ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Fusion Protein ◽  
Subunit Vaccine ◽  
Vaccine Candidates ◽  
Virus Fusion ◽  
Syncytial Virus ◽  
Young Mice

Immunovirological studies on human respiratory syncytial virus structural proteins

1986 ◽  
Vol 32 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Michel Trudel ◽  
Francine Nadon ◽  
Cécile Séguin ◽  
Simone Ghoubril ◽  
Pierre Payment ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Fusion Protein ◽  
Neutralizing Antibodies ◽  
Sodium Dodecyl ◽  
Human Respiratory Syncytial Virus ◽  
Structural Proteins ◽  
Membrane Glycoproteins ◽  
Protein Dimer ◽  
Syncytial Virus ◽  
Nucleoprotein N

Immunovirological studies suggest that human respiratory syncytial virus may well be composed of five structural proteins as are other members of the Paramyxoviridae family: the two external membrane glycoproteins H (90 000) and Fo (F1, 49 000; F2, 20 000; disulfide linked), the internal membrane protein M (34 000), the nucleoprotein N (42 000), and a protein (78 000) designated P that could be the equivalent of the polymerase of the morbillivirus and paramyxovirus genus. Neutralizing monoclonal antibodies showed, by immunoprecipitation and immunoblotting, that the fusion protein carries neutralizing epitopes. One monoclonal antibody, which shows a high neutralizing titer, immunoblotted directly with the F1 fragment (49 000) of the fusion protein. Analysis in mice of the immunogenicity of the structural proteins separated on sodium dodecyl sulphate gels indicated that, under our conditions, only the fusion protein dimer Fo and its F1 fragment were capable of inducing neutralizing antibodies.

scholarly journals Packaging and Prefusion Stabilization Separately and Additively Increase the Quantity and Quality of Respiratory Syncytial Virus (RSV)-Neutralizing Antibodies Induced by an RSV Fusion Protein Expressed by a Parainfluenza Virus Vector

2016 ◽  
Vol 90 (21) ◽  
pp. 10022-10038 ◽  
Author(s):  
Bo Liang ◽  
Joan O. Ngwuta ◽  
Richard Herbert ◽  
Joanna Swerczek ◽  
David W. Dorward ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Rhesus Monkeys ◽  
Neutralizing Antibodies ◽  
Vaccine Candidate ◽  
Parainfluenza Virus ◽  
F Protein ◽  
Syncytial Virus ◽  
Human Parainfluenza Virus ◽  
Type 3

ABSTRACTHuman respiratory syncytial virus (RSV) and human parainfluenza virus type 3 (HPIV3) are major pediatric respiratory pathogens that lack vaccines. A chimeric bovine/human PIV3 (rB/HPIV3) virus expressing the unmodified, wild-type (wt) RSV fusion (F) protein from an added gene was previously evaluated in seronegative children as a bivalent intranasal RSV/HPIV3 vaccine, and it was well tolerated but insufficiently immunogenic for RSV F. We recently showed that rB/HPIV3 expressing a partially stabilized prefusion form (pre-F) of RSV F efficiently induced “high-quality” RSV-neutralizing antibodies, defined as antibodies that neutralize RSVin vitrowithout added complement (B. Liang et al., J Virol 89:9499–9510, 2015, doi:10.1128/JVI.01373-15). In the present study, we modified RSV F by replacing its cytoplasmic tail (CT) domain or its CT and transmembrane (TM) domains (TMCT) with counterparts from BPIV3 F, with or without pre-F stabilization. This resulted in RSV F being packaged in the rB/HPIV3 particle with an efficiency similar to that of RSV particles. Enhanced packaging was substantially attenuating in hamsters (10- to 100-fold) and rhesus monkeys (100- to 1,000-fold). Nonetheless, TMCT-directed packaging substantially increased the titers of high-quality RSV-neutralizing serum antibodies in hamsters. In rhesus monkeys, a strongly additive immunogenic effect of packaging and pre-F stabilization was observed, as demonstrated by 8- and 30-fold increases of RSV-neutralizing serum antibody titers in the presence and absence of added complement, respectively, compared to pre-F stabilization alone. Analysis of vaccine-induced F-specific antibodies by binding assays indicated that packaging conferred substantial stabilization of RSV F in the pre-F conformation. This provides an improved version of this well-tolerated RSV/HPIV3 vaccine candidate, with potently improved immunogenicity, which can be returned to clinical trials.IMPORTANCEHuman respiratory syncytial virus (RSV) and human parainfluenza virus type 3 (HPIV3) are major viral agents of acute pediatric bronchiolitis and pneumonia worldwide that lack vaccines. A bivalent intranasal RSV/HPIV3 vaccine candidate consisting of a chimeric bovine/human PIV3 (rB/HPIV3) strain expressing the RSV fusion (F) protein was previously shown to be well tolerated by seronegative children but was insufficiently immunogenic for RSV F. In the present study, the RSV F protein was engineered to be packaged efficiently into vaccine virus particles. This resulted in a significantly enhanced quantity and quality of RSV-neutralizing antibodies in hamsters and nonhuman primates. In nonhuman primates, this effect was strongly additive to the previously described stabilization of the prefusion conformation of the F protein. The improved immunogenicity of RSV F by packaging appeared to involve prefusion stabilization. These findings provide a potently more immunogenic version of this well-tolerated vaccine candidate and should be applicable to other vectored vaccines.

scholarly journals Neutralization of Human Respiratory Syncytial Virus Infectivity by Antibodies and Low-Molecular-Weight Compounds Targeted against the Fusion Glycoprotein

2010 ◽  
Vol 84 (16) ◽  
pp. 7970-7982 ◽  
Author(s):  
Margarita Magro ◽  
David Andreu ◽  
Paulino Gómez-Puertas ◽  
José A. Melero ◽  
Concepción Palomo
Keyword(s):  
Molecular Weight ◽  
Respiratory Syncytial Virus ◽  
Vaccine Development ◽  
Human Respiratory Syncytial Virus ◽  
Heptad Repeat ◽  
Low Molecular Weight ◽  
Virus Infectivity ◽  
F Protein ◽  
Low Molecular Weight Compounds ◽  
Syncytial Virus

ABSTRACT Human respiratory syncytial virus (HRSV) fusion (F) protein is an essential component of the virus envelope that mediates fusion of the viral and cell membranes, and, therefore, it is an attractive target for drug and vaccine development. Our aim was to analyze the neutralizing mechanism of anti-F antibodies in comparison with other low-molecular-weight compounds targeted against the F molecule. It was found that neutralization by anti-F antibodies is related to epitope specificity. Thus, neutralizing and nonneutralizing antibodies could bind equally well to virions and remained bound after ultracentrifugation of the virus, but only the former inhibited virus infectivity. Neutralization by antibodies correlated with inhibition of cell-cell fusion in a syncytium formation assay, but not with inhibition of virus binding to cells. In contrast, a peptide (residues 478 to 516 of F protein [F478-516]) derived from the F protein heptad repeat B (HRB) or the organic compound BMS-433771 did not interfere with virus infectivity if incubated with virus before ultracentrifugation or during adsorption of virus to cells at 4°C. These inhibitors must be present during virus entry to effect HRSV neutralization. These results are best interpreted by asserting that neutralizing antibodies bind to the F protein in virions interfering with its activation for fusion. Binding of nonneutralizing antibodies is not enough to block this step. In contrast, the peptide F478-516 or BMS-433771 must bind to F protein intermediates generated during virus-cell membrane fusion, blocking further development of this process.

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