Engineering Enhanced Vaccine Cell Lines to Eradicate Vaccine-Preventable Diseases: The Polio Endgame.

van der Sanden SM1, Wu W2, Dybdahl-Sissoko N3, Weldon WC3, Brooks P2, O'Donnell J2, Jones LP2, Brown C3, Tompkins SM2, Oberste MS4, Karpilow J5,Tripp RA2.

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Abstract

Vaccine manufacturing costs prevent a significant portion of the world's population from accessing protection from vaccine-preventable diseases. To enhance vaccine production at reduced costs, a genome-wide RNAi screen was performed to identify gene knockdown events that enhanced poliovirus replication. Primary screen hits were validated in a Vero vaccine manufacturing cell line using attenuated and wild type poliovirus strains. Multiple single and dual gene silencing events increased poliovirus titers >20-fold and >50-fold, respectively. Host gene knockdown events did not affect virus antigenicity and CRISPR-Cas9-mediated knockout of the top candidates dramatically improved viral vaccine strain production. Interestingly, silencing of several genes that enhanced poliovirus replication also enhanced enterovirus 71, a clinically relevant virus for which vaccines are being targeted. The discovery that host gene modulation can markedly increase virus vaccine production dramatically alters mammalian cell-based vaccine manufacturing and should facilitate polio eradication using the inactivated poliovirus vaccine.

IMPORTANCE:

Using a genome-wide RNAi screen, a collection of host virus-resistance genes was identified that upon silencing increased poliovirus and enterovirus 71 production from 10-fold to >50-fold in a Vero vaccine manufacturing cell line. This study provides novel insights into enterovirus-host interactions, and describes an approach toward developing the next generation of vaccine manufacturing through engineered vaccine cell lines. The findings show that specific gene silencing and knockout events can enhance viral titers of both attenuated (Sabin) and wild polioviruses, a finding that should greatly facilitate global implementation of inactivated polio vaccine, as well as further reducing costs for live-attenuated oral polio vaccines. This work describes a platform-enabling technology applicable to most vaccine preventable diseases.