A Genetically Engineered Commercial Chicken Line Is Resistant to Highly Pathogenic Avian Leukosis Virus Subgroup J

Area of Science:

• Animal Science
• Genetics
• Virology

Background:

• Avian leukosis virus subgroup J (ALV-J) causes significant economic losses in the poultry industry.
• Current strategies to control ALV-J are limited due to the lack of vaccines and antiviral drugs.

Purpose of the Study:

• To evaluate the efficacy of a CRISPR/Cas9-induced mutation in the chicken sodium/hydrogen exchanger 1 (chNHE1) gene against ALV-J infection.
• To assess the impact of this genetic modification on disease development and bird performance.

Main Methods:

• Generation of genetically modified chickens (NHE1ΔW38) with a mutated chNHE1 receptor using CRISPR/Cas9.
• Infection of NHE1ΔW38 and non-transgenic (NHE1W38) chickens with the virulent ALV-J strain HPRS-103.
• Monitoring viral replication, antigen detection, weight gain, and histopathological analysis.

Main Results:

• The chNHE1 mutation (NHE1ΔW38) significantly impaired replication of the HPRS-103 ALV-J strain.
• ALV-J antigen was not detected in cloacal swabs from infected NHE1ΔW38 birds at later time points.
• NHE1ΔW38 chickens exhibited improved weight gain and absence of ALV-J-associated pathology compared to controls.

Conclusions:

• The chNHE1 mutation confers resistance to highly pathogenic ALV-J infection in a commercial chicken line.
• This genetic approach presents a viable strategy for controlling ALV-J and enhancing animal health in poultry farming.