A new study by U.S. scientists has demonstrated that cows have a "remarkable" ability to neutralize the HIV virus, a finding hailed by the researchers as "a significant step forward" that may offer insights for vaccine design.
The study, conducted with the support of the U.S. National Institutes of Health (NIH), found that the immune system of calves can rapidly develop antibodies which can neutralize the HIV virus.
The broadly neutralizing antibodies (bNAbs), scientists have observed, can be developed naturally by 10 to 20 percent of people living with HIV, but the process only begins about two years after infection.
The HIV virus may well have mutated during two years' time, and, according to a news release posted on the NIH website, scientists have so far been unsuccessful in prompting the human immune system to produce bNAbs by immunization.
When the researchers injected HIV immunogens into the bodies of four calves which they were experimenting with, the cows developed bNAbs between 30 and 35 days. The immunogen applied in the experiment can elicit bNAb responses "rapidly and constantly," the news release said.
The experiment marks the first time scientists have reliably triggered the production of antibodies to HIV in humans or animals by immunization.
Unlike human beings, cows do not get HIV and the bNAbs they generate are not likely to be suitable for clinic use in humans in their current form. But scientists believe exploring this rapid production of bNAbs may help with the design of a new vaccine to fight HIV.
"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," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, a member of the NIH.
Although the reason why the powerful antibodies can be produced by cattle remains unclear, one theory links the phenomenon to the animals' extensive gastrointestinal systems, which have multi-chambered stomachs and a robust population of bacteria in their digestive tracts to help break down tough grasses, according to the study.