Department of Microbiology and Physiological Systems
Animals; Antibodies, Neutralizing; Antibodies, Viral; Enzyme-Linked Immunosorbent Assay; Female; Genetic Vectors; Immunoglobulin G; Mice, Inbred BALB C; Neutralization Tests; Newcastle disease virus; Recombinant Fusion Proteins; Respiratory Syncytial Virus Vaccines; Respiratory Syncytial Viruses; Vaccines, Synthetic; Vaccines, Virus-Like Particle; Viral Fusion Proteins
Immunity | Immunology of Infectious Disease | Immunoprophylaxis and Therapy | Virology
Virus-like particles (VLPs) built on the Newcastle disease virus (NDV) core proteins, NP and M, and containing two chimeric proteins, F/F and H/G, composed of respiratory syncytial virus (RSV) fusion protein (F) and glycoprotein (G) ectodomains fused to the transmembrane and cytoplasmic domains of the NDV F and HN proteins, respectively, stimulate durable, protective RSV neutralizing antibodies in mice. Here, we report the properties of VLPs constructed to contain mutant RSV F protein ectodomains stabilized in prefusion (pre-F/F) or postfusion (post-F/F) configurations. The structures of the chimeric proteins assembled into VLPs were verified immunologically by their reactivities with a conformationally restricted anti-F protein monoclonal antibody. Following immunization of mice, without adjuvant, pre-F/F-containing VLPs induced significantly higher neutralizing antibody titers than the post-F/F-containing VLPs or the wild-type F/F-containing VLPs after a single immunization but not after prime and boost immunization. The specificities of anti-F IgG induced by the two mutant VLPs were assessed by enzyme-linked immunosorbent assay (ELISA) using soluble forms of the prefusion and postfusion forms of the F protein as targets. While both types of VLPs stimulated similar levels of IgG specific for the soluble postfusion F protein, titers of IgG specific for prefusion F induced by the pre-F/F-containing VLPs were higher than those induced by post-F/F-containing VLPs. Thus, VLPs containing a stabilized prefusion form of the RSV F protein represent a promising RSV vaccine candidate.
IMPORTANCE: The development of vaccines for respiratory syncytial virus has been hampered by a lack of understanding of the requirements for eliciting high titers of neutralizing antibodies. The results of this study suggest that particle-associated RSV F protein containing mutations that stabilize the structure in a prefusion conformation may stimulate higher titers of protective antibodies than particles containing F protein in a wild-type or postfusion conformation. These findings indicate that the prefusion F protein assembled into VLPs has the potential to produce a successful RSV vaccine candidate.
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DOI of Published Version
J Virol. 2015 Jul;89(13):6835-47. doi: 10.1128/JVI.00384-15. Epub 2015 Apr 22. Link to article on publisher's site
Journal of virology
McGinnes Cullen, Lori; Schmidt, Madelyn R.; Kenward, Sarah A.; Woodland, Robert T.; and Morrison, Trudy G., "Murine immune responses to virus-like particle-associated pre- and postfusion forms of the respiratory syncytial virus F protein" (2015). Open Access Articles. 2704.