Cows could be the answer to finally helping scientists develop an AIDS vaccine after a “surprising set of results” in studying cattle antibodies.
The study was carried out by researchers at the International Aids Vaccine Initiative and the Scripps Research Institute.
Medical experts have long struggled with creating a antibody-based jab that could be broadly effective against the huge diversity in HIV viruses, but the successful animal model marks an important step forward.
Scientists have known for some time that people living with chronic HIV infection produce broadly neutralising antibodies (bnAbs), some of which are capable of reaching areas that are commonly concealed on the HIV virus.
The virus uses fences of sugars on its surface to protect vulnerable sites, and only antibodies with long ‘arm-like loops’ are able to circumvent this barrier and get in.
And to create these powerful HIV-blocking antibodies with long-arm structures usually takes years in humans, and only happen in 5-15% of people who are HIV positive.
Not only that, but HIV produces irrelevant proteins to distract the human immune system and waste its time producing antibodies against these red herring proteins.
But studies have shown that antibodies in cattle also feature these extra-long hoops, so scientists wondered if they could help fight HIV.
Professor Dennis Burton, 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?”
Of course cows cannot be infected with HIV, but the results of the study did confirm the team’s speculation that the long-arm loops are key.
As all four cows immunised in the study (100% of the sample), were able to start producing broadly neutralising antibodies within 35-53 days, rather than the years it takes humans.
Devin Sok, at the International AIDS Vaccine Initiative, said: “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.”
“The response blew our minds,” Sok told BBC News.
These findings illuminate a new goal for HIV vaccine researchers: by increasing the number of human antibodies with long loops, we might have an easier chance of eliciting protective bnAbs by vaccination.