Future HIV vaccine could trigger body’s immune system
A new vaccine to stimulate the body’s immune system could offer a cure for Human Immuno-deficiency Virus (HIV). The ‘kick and kill’ strategy aims to eradicate the virus, by stimulating the immune system – the body’s natural defence mechanism – with a vaccine.
Researchers believe the injection could flush out dormant HIV hiding in white blood cells with a chemical ‘kick’, allowing a boosted immune system to identify and kill the cells.
The theory, developed by researchers at University College London, the University of Oxford and the University of North Carolina, is based on a single patient case study. The study was published in the journal Clinical Infectious Diseases. Study co-author Dr. Ravi Gupta, of UCL, said: “‘Our study shows that the immune system can be as powerful as the most potent combination drug cocktails.
“We’re still a long way from being able to cure HIV patients, as we still need to develop and test effective vaccines, but this study takes us one step closer by showing us what type of immune responses an effective vaccine should induce.”
The study looked at a single 59-year-old man in London who was an ‘elite controller’ – meaning his immune system could control HIV for a long period of time without his needing treatment. Elite controllers, who make up 0.3 per cent of HIV patients, eventually require treatment to prevent progression to Acquired Immune Deficiency Syndrome (AIDS).
But they can go a lot longer without treatment because their immune systems are more active against HIV. The patient in the study had both HIV and myeloma, a cancer of the bone marrow. The bone marrow produces white blood cells, including those that help to control HIV.
Man-made DNA could help in the fight against HIV Pioneering new treatments for HIV, flu, ebola and cancer are being developed by scientists harnessing man-made DNA. Experts have discovered how to create strands of artificial DNA, each mimicking a different killer disease, and inject them into patients. The idea is that the patients’ immune systems will then be able to recognise the threats and eliminate them.
Inovio, one of the companies behind the technique, has begun trials in humans, after strong results in the lab. The American company is using the method to attack flu, ebola and certain types of cancer – as well as HIV and hepatitis. Experts have already started trials on female patients to see if they can stop them developing cervical cancer.
To treat the patient’s myeloma, his bone marrow was completely removed and replaced using his own stem cells. When the bone marrow was removed, the immune system was severely impaired, allowing the HIV to re-activate and replicate. This caused the level of virus in his bloodstream to rise from fewer than 50 copies per millilitre to approximately 28,000 copies per ml before is immune system’s function returned.
When the patient’s immune function returned about two weeks after the transplant, the levels of HIV in his bloodstream rapidly fell. His immune system reduced HIV levels at a similar rate to the most powerful treatments available, bringing them back down to 50 copies per ml within six weeks.
Professor Deenan Pillay, also of UCL, said: “By measuring the strength of the immune system required to keep this virus under control in this rare individual, we have a better idea of the requirements for successful future treatment. “We also managed to identify the specific immune cells that fought the infection.
“This is a single patient study, but nevertheless it is often the unusual patients who help us to understand the HIV disease process.” The man was not given any anti-HIV drugs, due to concerns about side-effects affecting his cancer treatment.
The researchers noted it is possible that an equally strong immune response in combination with powerful drugs could have cured the HIV completely, however they state that is far from certain. Dr. Ravi Gupta, of UCL, said: “Our study shows that the immune system can be as powerful as the most potent combination drug cocktails.
We’re still a long way from being able to cure HIV patients, but this study takes us one step closer, showing us what type of immune responses an effective vaccine should induce.”
“We need to be cautious in interpreting observations from a single subject,” said Dr Nilu Goonetilleke, who began working on the study at the University of Oxford and is now at the University of North Carolina at Chapel Hill.
“However, demonstration even from a single subject, that our immune system can rapidly control HIV-1 tells us a lot about the types of immune responses we should target and augment through vaccination.” Gupta adds: “Drugs to stimulate reactivation of dormant HIV are still imperfect, and we do not know if they would be able to flush out all of the HIV from the body.
“Likewise, it remains to be seen whether a vaccine could enable a normal HIV patient’s immune system to kill HIV with the full strength of an elite controller. “Our study is a proof of principle and the results are promising, but it is unlikely to lead to a cure for at least a decade.’
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