Genetic insertion of mouse Myxovirus-resistance gene 1 increases innate resistance against both high and low pathogenic avian influenza virus by significantly decreasing replication in chicken DF1 cell line

Authors: BRIGGS, KELSEY - Orise Fellow; CHRZASTEK, KLAUDIA - Animal And Plant Health Agency; SEGOVIA, KAREN - Csl Seqirus; MO, JOHN - Orise Fellow; Kapczynski, Darrell

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Diseases caused by viral pathogens are of vital importance to the poultry industry and ultimately U.S. consumers. Current control of avian viral pathogens is through the integration of biosecurity, vaccines (when available or permissible), and, in some cases, enhanced genetic disease resistance or tolerance. Avian influenza is a disease caused by infection with avian influenza virus (AIV). These viruses are naturally found in wild aquatic birds and can infect domestic poultry causing significant mortality and financial losses. In these studies we inserted a mouse gene with demonstrated ability to enhance resistance against AIV into the chicken genome. The purpose was to determine if that resistance could be transferred. Results demonstrate that expression of the mouse gene decreased virus replication in chicken cells. This approach offers opportunity to develop birds that are resistant to AIV.

Technical Abstract: Avian influenza virus (AIV) poses a threat to animal and human health. In recent years, global outbreaks of AIV have resulted in the loss of hundreds of millions of wild birds and poultry. Apart from biosecurity measures, vaccination and culling are the only approved strategies for disease control. Future outbreaks may be prevented with the creation of gene-edited birds with enhanced disease-resistance to AIV. Myxovirus-resistance proteins (Mx) are key mediators of the antiviral response that block viral replication of several viruses. The effectiveness of chicken Mx (Ck Mx) is controversial, however mouse Mx (Mu Mx1) is a strong antiviral with known effectiveness against AIVs. Here, Mu Mx1 is stably introduced into an immortal chicken cell line (DF1) to enhance the innate immune response towards low pathogenic avian influenza virus (LPAIV) and highly pathogenic avian influenza virus (HPAIV). Following challenge, titers of both LPAIV and HPAIV were significantly decreased in DF1 cells expressing Mu Mx1 cells at 24 hours post infection. In addition, considerably less cytopathic effect and matrix protein staining was observed in gene-edited cells expressing Mu Mx1, which suggests Mu Mx1 is broadly effective against multiple AIV subtypes. A pretreatment with chicken interferon-alpha, known to upregulate Mx expression, resulted in an additional 5-10-fold decrease in viral titers compared to the virus grown in Mu Mx1-expressing cells alone. This work provides the foundational studies for using Mu Mx1 in chickens to increase disease resistance to AIV.