Could This Cow Save Your Life?

One of the biggest challenges in combating HIV is its ability to mutate frequently, which has made it incredibly difficult to find a long-term vaccine. Typically, a vaccine would involve giving someone a small amount of the virus, so their immune system can build antibodies to fight it. However, the way HIV hijacks the immune system prevents it from building these antibodies.

But research conducted by the International AIDS Vaccine Initiative and the Scripps Research Institute tested an HIV vaccine on cows, and it’s showing surprising results.

“From the early days of the epidemic, we have recognized that HIV is very good at evading immunity, so exceptional immune systems that naturally produce broadly neutralizing antibodies to HIV are of great interest — whether they belong to humans or cattle,” Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, recently told BBC News, in response to the study.

Researchers previously discovered that a very small number of people living with the virus may eventually develop “broadly neutralizing antibodies” themselves, which attack parts of the virus that cannot mutate. These “elite controllers” represent only one percent of those living with HIV — generally those of European decent. But for the general population, a vaccine would need to provide the antibodies itself or somehow induce the immune system to manufacture them.

Given that no prior study has been able to “reliably elicit” broadly neutralizing antibodies to HIV in humans or animal models, the cow study represents a significant step forward.

“This is really important because we hadn’t been able to do it, period,” said Dr. Devin Sok from the Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery at The Scripps Research Institute in La Jolla, California. “Who would have thought cow biology was making a significant contribution to HIV?”

Researchers found that not only were the cows able to produce the antibodies, but they did so quite rapidly. “The response blew our minds,” said Sok, who was also one of the lead authors on the study, published in the journal Nature. “It was just insane how good it [worked]. In humans it takes three to five years to develop the antibodies we’re talking about.”

That reliable speed would be necessary to mass produce any HIV vaccine. It is believed that cows evolved particularly robust immune systems due to their complex, bacteria-packed, four-stomach digestive system.

Researchers also found that these cow antibodies neutralized 20 percent of HIV strains within 42 days and by day 381, they had neutralized 96 percent of the strains tested in the lab.

“The potent responses in this study are remarkable,” said Dr. Dennis Burton, another Scripps researcher on the project. “Unlike human antibodies, cattle antibodies are more likely to bear unique features and gain an edge over HIV.” That unique feature is apparently the antibodies’ “long and loopy structure,” according to the BBC.

The U.S. National Institutes of Health was quoted in BBC coverage as calling the findings of “great interest.” While vaccines are typically used solely to prevent the transmission of a virus, in the case of HIV, researchers are also investigating their use in treating those already living with the virus. Only time will tell whether cows will become essential to an HIV vaccine’s success.