A dramatic advance in the formation of antibodies for the COVID-19 researchers from the University of California, Davis, managed to produce antibodies against the spike protein of SARS-CoV-2 in chicken eggs.
The work was published on July 9 in the journal viruses.
“The beauty of the system is that you can produce a lot of antibodies in the birds,” said Rodrigo Gallardo, a professor of poultry medicine in the Department of Population Health and Reproduction at the UC Davis School of Veterinary Medicine. “In addition to a low cost to produce these antibodies in chickens, they can be updated very quickly by using updated antigens to hyperimmunize chickens, allowing protection against current variant strains.”
Birds produce a type of antibody called IgY, comparable to IgG in humans and other mammals. IgY does not cause allergy or trigger immune reactions when injected into humans. IgY appears both in the serum of birds and in their eggs. Since a hen lays about 300 eggs a year, she can get a lot of IgY, Gallardo said.
Gallardo and colleagues immunized chickens with two doses of three different vaccines based on the SARS-CoV-2 spike protein or receptor-binding domain. They measured antibodies in blood samples from chickens and in egg yolks three and six weeks after the last immunization.
The purified antibodies were tested for their ability to block the coronavirus from infecting human cells at the National Center for Biodefense and Infectious Diseases at George Mason University in Virginia.