They discovered that the cows very rapidly developed bNAbs to HIV in their blood.
Cows may play an unlikely role in the fight against HIV.
The scientists had a question: what would happen if they immunise cows with an HIV immunogen?
And indeed, the scientists injected HIV immunogens known as BG505 SOSIP into the flanks of four calves, and showed a quick immune response with a lot of broadly neutralising antibodies created.
Cows do not get HIV and bovine antibodies are unsuitable for clinical treatment for humans in their current form. The similarities between those long loops in cows and people led them to a simple question: “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?” said Devin Sok, Director, Antibody Discovery and Development and IAVI, in a press release.
The TRSI investigators isolated specific antibodies from the immunized calves to study their properties. Called NC-Cow 1, it neutralized about two-thirds of a panel of diverse HIV isolates. As the paper highlights the antibodies of the cows are capable of neutralizing almost 20% of HIV strains within only 42 days or 6 weeks. The potent responses in this study are remarkable because cattle seem to produce bNAbs in a relatively short amount of time.
Previous experiments led by bovine-antibody expert Vaughn Smider at The Scripps Research Institute (TSRI) showed that cattle antibodies also feature extra-long loops, which might access hard epitopes that human antibodies can not.
If researchers could induce antibodies with long HCDR3s in humans, “then that could be the basis of getting a vaccine to work”, Smider says. But when given to monkeys before exposure to a virus similar to HIV, the antibodies prevent infection. Considering these features, scientists realised that Bnabs bore resemblance to the types of antibodies found in cows.
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.
One theory links the more powerful antibodies produced by cows to their extensive gastrointestinal systems, which comprise of multi-chambered stomachs populated by plentiful bacteria to help break drown tough grasses. However, they do facilitate further research into the development of HIV treatments. The research is the first-of-its-kind immunization evolution, where the researchers have found out how animals quickly generate particular kinds of an antibody which can neutralize HIV.
The pharmaceutical industry already uses cattle and other animals associated with agriculture, such as chickens and pigs, to produce antibody therapeutics and prophylactics, immunogens for vaccines and therapeutic hormones. People are working to humanise animal antibodies such that the immune system doesn’t recognise them, but this work is in its infancy.