The latest recruits in the fight against COVID-19 are munching hay in a South Dakota barn. A biotech company has coaxed genetically modified cows to pump out human antibodies that subdue SARS-CoV-2, the pathogen causing the deadly disease, and it plans to start clinical trials of them this summer.
To manufacture antibodies for treating or preventing diseases, companies typically turn to sources such as cultured cells or tobacco plants. But almost 20 years ago, researchers began to develop the approach now pursued by SAb Biotherapeutics of Sioux Falls, South Dakota, to produce antibodies on the hoof.
The company genetically alters dairy cows so that certain immune cells carry the DNA that allows people to make antibodies. That upgrade enables the animals to manufacture large quantities of human antibodies against a pathogen protein injected into them, such as the “spike” surface protein of the new coronavirus. “Essentially, the cows are used as a giant bioreactor,” says viral immunologist William Klimstra of the University of Pittsburgh, who has been analyzing the bovinemade antibodies’ potency against SARS-CoV-2.
Cows make good antibody factories, and not just because they have more blood than smaller animals engineered to synthesize human versions of the proteins. Their blood can also contain twice as many antibodies per milliliter as human blood ….