Development of high-yield influenza A virus vaccine viruses

Jihui Ping,Chairul A Nidom,Adam Fitch,Masaki Imai,Yoshihiro Kawaoka,Catherine A Macken,Elodie Ghedin,Gabriele Neumann,Tiago J.S Lopes,Eileen A Maher

doi:10.1038/ncomms9148

Abstract

Vaccination is one of the most cost-effective ways to prevent infection. Influenza vaccines propagated in cultured cells are approved for use in humans, but their yields are often suboptimal. Here, we screened A/Puerto Rico/8/34 (PR8) virus mutant libraries to develop vaccine backbones (defined here as the six viral RNA segments not encoding haemagglutinin and neuraminidase) that support high yield in cell culture. We also tested mutations in the coding and regulatory regions of the virus, and chimeric haemagglutinin and neuraminidase genes. A combination of high-yield mutations from these screens led to a PR8 backbone that improved the titres of H1N1, H3N2, H5N1 and H7N9 vaccine viruses in African green monkey kidney and Madin–Darby canine kidney cells. This PR8 backbone also improves titres in embryonated chicken eggs, a common propagation system for influenza viruses. This PR8 vaccine backbone thus represents an advance in seasonal and pandemic influenza vaccine development.

Highlights

Vaccination is one of the most cost-effective ways to prevent infection
We carried out a comprehensive study to develop a Puerto Rico/8/34 (PR8) vaccine backbone that significantly improves the virus yield of various seasonal and pandemic influenza vaccines strains in cell culture
Based on UW-PR8, we generated the following nine virus libraries: six libraries possessing random mutations in each of the ‘internal’ genes; one library possessing random mutations in the genes encoding the PB2, PB1 and PA proteins, which together form the viral polymerase complex; one library possessing random mutations in the PB2 and NS genes, which code for the major virulence factors PB2 and NS1, respectively; and one library possessing random mutations in the NS and M genes since the M1 protein is associated with high-growth properties[31] (Fig. 1)

Summary

Introduction

Vaccination is one of the most cost-effective ways to prevent infection. Influenza vaccines propagated in cultured cells are approved for use in humans, but their yields are often suboptimal. We screened A/Puerto Rico/8/34 (PR8) virus mutant libraries to develop vaccine backbones (defined here as the six viral RNA segments not encoding haemagglutinin and neuraminidase) that support high yield in cell culture. A combination of high-yield mutations from these screens led to a PR8 backbone that improved the titres of H1N1, H3N2, H5N1 and H7N9 vaccine viruses in African green monkey kidney and Madin–Darby canine kidney cells. This PR8 backbone improves titres in embryonated chicken eggs, a common propagation system for influenza viruses. The same backbone can improve yield in egg culture systems

Methods

Results

Conclusion