IRF3/IRF7 knockout cell lines for enhanced morbillivirus growth and vaccine production

Overview

This technology leverages CRISPR-Cas9 gene editing to develop IRF3 and IRF7 knockout cell lines that significantly enhance the growth of Morbillivirus and related paramyxoviruses. By disrupting key regulators of the host antiviral innate immune response, these cell lines enable dramatically higher viral titers, offering substantial benefits for vaccine manufacturers, virology researchers, and biopharmaceutical companies. The approach builds on validated results showing 5-20 fold increases in viral titers for porcine viruses such as PEDV, SVA, PIV5, SeV, and GETV using similar gene knockout strategies.

The core innovation targets the interferon regulatory factors IRF3 and IRF7, which are primary transcriptional factors downstream of the RIG-I-like receptor (RLR) and Toll-like receptor (TLR) signaling pathways. By knocking out these genes, the host cell's antiviral interferon response is compromised, allowing viruses to replicate more efficiently and reach higher titers. Given that Parainfluenza virus 5 (PIV5) and Sendai virus (SeV) are paramyxoviruses phylogenetically close to Morbillivirus, this approach is highly promising for enhancing Morbillivirus production, including Canine Distemper Virus (CDV).

Technical specifications

Key features:

• CRISPR-Cas9 mediated knockout of IRF3 and IRF7 genes to suppress host antiviral interferon responses
• Development of double-knockout cell lines targeting both IRF3 and IRF7 simultaneously
• Additional gene knockouts targeting interferon response and apoptosis-related host genes
• Compatible with established virus titration methods using CDV infectious clones and EGFP-expressing reporter viruses
• Expected 10-fold or greater increase in Morbillivirus titers compared to parental cell lines

How it works:

The technology exploits the host innate immune signaling cascade. When cells are infected by RNA viruses, pattern recognition receptors (including RIG-I-like receptors and Toll-like receptors) activate signaling pathways that converge on IRF3 and IRF7 transcription factors. These factors drive the production of type I interferons (IFN-α and IFN-β) and antiviral factors that suppress viral replication. By using CRISPR-Cas9 to knock out IRF3 and/or IRF7, this antiviral response is attenuated, resulting in enhanced viral replication, increased cytopathic effects, and ultimately higher viral yields.

Applications:

• High-titer Morbillivirus stock production for vaccine manufacturing
• Cost reduction in biopharmaceutical virus production workflows
• Research tool for studying Morbillivirus biology and host-pathogen interactions
• Potential platform for enhancing growth of other paramyxoviruses and related RNA viruses

Technology readiness level

The underlying gene knockout technology has been validated and demonstrated to enhance viral titers by 5-20 fold for multiple porcine viruses. Results from the IRF3/IRF7 knockout ST cell line studies are forthcoming in the journal Biotechnol J. The research team has already developed a CDV infectious clone and an EGFP-expressing CDV reporter virus to facilitate virus titration and validation. Future work will focus on developing IRF3/IRF7 double-knockout cell lines and additional gene knockouts targeting interferon and apoptosis pathways, with comprehensive characterization of growth properties, cytokine responses, apoptosis profiles, and virus growth capabilities. The technology is positioned for collaborative development and licensing partnerships with biopharmaceutical companies interested in optimizing their virus production pipelines.