For the first time, gene-edited pigs successfully resist costly virus

June 21, 2018

Last year, the University of Edinburgh announced that a team of its researchers had used advanced genetic techniques to produce pigs that were potentially resistant to a viral infection that costs the swine industry billions of dollars each year.

Now, those pigs have been put to the test. The team recently exposed the gene-edited pigs to Porcine Reproductive and Respiratory Syndrome (PRRS). After exposure, none of the animals became ill, and blood tests revealed no trace of the virus. The researchers also note that the pigs don’t show any signs that the change in their DNA has had any impact on their well-being.

Gene-editing technology has been used to make the pigs resistant to both major subtypes of the PRRS virus, an infection that causes severe breathing problems in young pigs and breeding failures in pregnant females. It’s endemic in most pig-producing parts of the world and no vaccine is available, making it one of the greatest challenges dealt with by pig producers.

How it works

The PRRS virus targets immune cells called macrophages. A particular molecule belonging to all macrophages, called CD163, plays a role in allowing the PRRS virus to get a foothold in the body. So, if CD163 was gone, PRRS wouldn’t infect a pig, the researchers theorized.

The research team used a gene-editing tool called CRISPR/Cas9 to cut out a small section of the CD163 gene in the pigs’ DNA code, allowing the animals to become immune to the virus. Lab tests on cell samples taken from the pigs suggested they had been successfully made immune, but this is the first time the pigs themselves have faced exposure.

Whether PRRS-resistant pigs will become commercially mainstream or not in the next few years depends on the future of public opinion and governmental regulation on gene-edited meat, which is different from genetically modified meat.

“Genome editing offers opportunities to boost food security by reducing waste and losses from infectious diseases, as well as improving animal welfare by reducing the burden of disease,” said lead researcher Alan Archibald. “Our results take us closer to realizing these benefits and specifically address the most important infectious disease problem for the pig industry worldwide.”

Category: Genomics