Cow antibodies may be key to effective AIDS vaccine

Researchers have found a way to elicit powerful, HIV-blocking antibodies in cows in weeks instead of years, which may lead to an effective AIDS vaccine.


The study, published July 20 in Nature, showed that the HIV-blocking antibodies can be obtained from cows in a matter of weeks compared to the years it takes for the same process in humans.

“One approach to a preventive HIV vaccine involves trying to elicit broadly neutralizing antibodies in healthy people, but so far the experiments have been unsuccessful, in both human and animal studies,” Devin Sok, director of the Antibody Discovery and Development at the International AIDS Vaccine Initiative, or IAVI, said in a press release.

“This experiment demonstrates that not only is it possible to produce these antibodies in animals, but we can do so reliably, quickly, and using a relatively simple immunization strategy when given in the right setting.”
In some people with chronic HIV infection, their bodies produce broadly neutralizing antibodies, or bnAbs, which can overcome high levels of diversity in HIV. One type of bnAb uses long arm-like loops that can reach concealed areas on the virus’s surface to block infection.

Previous studies showed that cattle antibodies also feature extra-long loops that might access hard to reach epitopes where human antibodies cannot.

Researchers immunized cows with an immunogen known as BG505 SOSIP, which closely mimics the protein target.

All four cows immunized with BG505 SOSIP elicited bnAbs to HIV within 35-52 days compared to the several years it takes to develop those same bnAbs in humans, if they develop them at all.

“It’s a remarkably simple and profound idea,” Sok, said. “Since we know that some human bnAbs have longer-than-average loops, would immunizing animals with similar antibody structure result in the elicitation of bnAbs against HIV?”

By Amy Wallace