Could cows be the clue that leads to an HIV vaccine?

"Cows have shown an 'insane' and 'mind-blowing' ability to tackle HIV which will help develop a vaccine, say US researchers," BBC News reports.

The report is based on new research in cows that were immunised against HIV before having their immune response to HIV assessed. There's currently no vaccine for HIV because the virus mutates so easily.

Scientists aim to develop a vaccine that is not only potent (produces a strong immune system response), but also causes the immune system to make "broadly neutralising antibodies" (able to protect against many different strains of virus).

The four cows in this study were immunised against HIV with a specially developed vaccine to test both strength and "breadth". Some cows developed a weak response with reasonable breadth (20% – or it helped protect against 1 in 5 strains tested in the lab) at 42 days. One cow in particular showed an impressive immune response to most of the lab strains of HIV ("96% breadth") 381 days after being vaccinated.

This research, done in a small number of cows, may help scientists work out if immune proteins made in cows could potentially be used to protect humans against a range of HIV strains.

While this is certainly welcome news, it doesn't mean an effective HIV vaccine is guaranteed to appear in the future. The most effective way to protect yourself from HIV is to always use a condom during sex, including oral and anal sex. Men who have sex with other men are particularly at risk if they don't practise safe sex.

Read more advice about HIV and gay health.

Where did the story come from?

The study was carried out by researchers from The Scripps Research Institute the International AIDS Vaccine Initiative, Texas A&M University, Kansas State University, and Ragon Institute of MGH, MIT and Harvard, all in the US.

The research was funded by various grants from the International AIDS Vaccine Initiative, the National Institutes of Health, the Centre for HIV/AIDS Vaccine Immunology and Immunogen Discovery and the US Department of Agriculture. The study was published in the peer-reviewed medical journal Nature.

The UK media reporting was generally accurate and made clear the research was carried out in cows and not humans. However, the Mail Online's claim that "An injection may soon be available that prevents the virus spreading and could rid sufferers of the infection" is incredibly optimistic.

This research is at a very early stage and will need to be repeated and refined before testing in humans is considered. There is no imminent vaccine for HIV.

What kind of research was this?

This was an investigational laboratory study carried out using cows. Researchers attempted to immunise cows against HIV and assessed their response to the vaccine.

HIV infects the body's immune system, causing progressive damage that eventually stops the body's ability to fight off infection. The virus attaches itself to immune cells that protect the body against bacteria, viruses and other germs. Once HIV has attached itself, it enters the cell and uses it to create thousands of copies of itself. The copies then leave the original immune cell and kill it in the process.

The process continues until the number of immune cells is so low, the immune system stops working. This process can take as long as 10 years, during which time the person may feel and appear to be well.

Thankfully, due to medical advances, antiretroviral drugs are now available that help protect the immune system from further damage and prevent secondary infections.

What did the research involve?

Researchers aimed to immunise cows with a substance called an immunogen, which are designed to provoke an immune response.

In this study the researchers used an immunogen called BG505 SOSIP. This mimics the outside of the HIV virus to produce an immune response. Researchers were able to see if the immunogens were "broad" (could neutralise many different viral strains) and potent by measuring how long it took for the immune response to occur; the quicker the response the more potent a vaccine tends to be.

Researchers chose to look at cows because, unlike most animals, they have longer amino acid chains.  Amino acids are the "building blocks" of proteins. Previous research has found that a small proportion of people with HIV who develop a level of natural immunity to the virus also have similarly long amino acid chains.

Four six-month-old calves were immunised with the BG505 SOSIP immunogen and the researchers looked at the subsequent immune response.
 

What were the basic results?

All cows developed immune cells to HIV 35 to 50 days following two injections. One cow showed an immune response that could neutralise 20% of HIV strains tested in the lab in 42 days and another neutralised 96% of HIV strains in 381 days.

When analysing the proteins created as part of the immune response, the researchers found that one in particular binds to a key HIV site that the virus uses to infect cells.

How did the researchers interpret the results?

The researchers conclude that they "have shown that immunization with a well-ordered immunogen in cows reliably and rapidly elicits broad and potent neutralizing serum responses in contrast to previous experiments in other animals."

Conclusion

This early stage research on cows indicates that they had a broad and quick immune response to HIV infection when given a specific vaccine. Because the immune proteins produced in cows are able to neutralise many different strains of HIV virus, the authors suggest this potentially gives them an edge over the human proteins that have been looked at so far.

As always with animal studies it is important to remember that what works in cows might not work in the same way in humans. Many drug studies that appear promising at first, fall at the first hurdle once humans are involved.

The study was also carried out on just four cows and the most promising finding – neutralisation of 96% of HIV strains in 381 days – was found in just one cow. It is therefore best seen as promising early research, rather than a proven cure.

While we all hope an HIV vaccine or cure may be on the horizon, until that time, using a condom during penetrative, oral and anal sex is the most effective method of preventing infection with HIV.