Respiratory Syncytial Virus Fusion Glycoprotein Expressed in Insect Cells Form Protein Nanoparticles That Induce Protective Immunity in Cotton Rats

University of Iowa, United States of America
PLoS ONE (Impact Factor: 3.23). 11/2012; 7(11):e50852. DOI: 10.1371/journal.pone.0050852
Source: PubMed


Respiratory Syncytial Virus (RSV) is an important viral agent causing severe respiratory tract disease in infants and children as well as in the elderly and immunocompromised individuals. The lack of a safe and effective RSV vaccine represents a major unmet medical need. RSV fusion (F) surface glycoprotein was modified and cloned into a baculovirus vector for efficient expression in Sf9 insect cells. Recombinant RSV F was glycosylated and cleaved into covalently linked F2 and F1 polypeptides that formed homotrimers. RSV F extracted and purified from insect cell membranes assembled into 40 nm protein nanoparticles composed of multiple RSV F oligomers arranged in the form of rosettes. The immunogenicity and protective efficacy of purified RSV F nanoparticles was compared to live and formalin inactivated RSV in cotton rats. Immunized animals induced neutralizing serum antibodies, inhibited virus replication in the lungs, and had no signs of disease enhancement in the respiratory track of challenged animals. RSV F nanoparticles also induced IgG competitive for binding of palivizumab neutralizing monoclonal antibody to RSV F antigenic site II. Antibodies to this epitope are known to protect against RSV when passively administered in high risk infants. Together these data provide a rational for continued development a recombinant RSV F nanoparticle vaccine candidate.

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Available from: David C Flyer, May 28, 2014
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    • "Indeed, a similar approach has been adapted for the preparation of protein nanoparticles comprised of amphiphilic antigens, where the protein micelles are prepared by extraction with non-ionic detergents from Sf9 insect cells expressing the recombinant antigen. In a compelling example, a slightly genetically modified full-length form of the RSV fusion (F) surface glycoprotein was extracted and purified from insect cell membranes and used to create protein nanoparticle micelles of ~40 nm diameter, where the trimeric F protein assembled into rosettes exposing conformational epitopes similar to those of the post-fusion F conformation and able to raise neutralizing Abs[103]. In very recent clinical trials, these RSV F antigen nanoparticles appeared safe, promoted immunogenicity, and reduced RSV infections[104], raising high expectations for a nanoparticle vaccine against RSV.[98]Abbreviations: "
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    • "The utility of SE-UHPLC separations has been realized in many areas of fundamental biochemistry research. In this capacity, these size separations have primarily been used to monitor the purity of laboratory-produced protein-related compounds [77] [78] [79] [80] [81]. In other examples, SE-UHPLC has been used as a purification step to purify cross-linked proteins in the study of cellular processes [82], and has also proved useful in protein-binding studies where differences in hydrodynamic radii between the reactant and the product can be used to advantage [83] [84]. "
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    • "Competitive inhibition by cotton rat sera of the binding of palivizumab monoclonal antibody (ASD Specialty Heath Care Inc., Chicago IL) was measured by an ELISA method as previously described [25]. Serum RSV virus neutralization titers were determined as described previously [25] "
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