Sunday 23 July 2017

Cure for HIV moves closer as scientists snip virus from animal cells

The HIV virus attacks and kills immune cells leaving patients highly vulnerable to other infections.
The HIV virus attacks and kills immune cells leaving patients highly vulnerable to other infections.

Sarah Knapton

A cure for HIV has moved a step closer after scientists proved they can snip away the virus from infected cells, a procedure that they hope will stop the virus ever returning.

The HIV virus attacks and kills immune cells leaving patients highly vulnerable to other infections.

But scientists in the US have shown it is possible to use state-of-the-art genetic editing technology to literally cut away the virus from the DNA of cells.

Researchers at Lewis Katz School of Medicine at Temple University, completely shut down the virus and eliminated it from the tissues of mice which had been transplanted with human immune cells and infected with HIV.

The latest experiment, which was led by Dr Wenhui Hu follows on from same team's previous research, in which they managed to delete HIV-1 from the genome of most tissues.

At the time British experts said the treatment would effectively ‘engineer the body to cure itself from the inside’ while charities hailed the breakthrough was 'very exciting.'

"Our new study is more comprehensive," said Dr Hu.

"We confirmed the data from our previous work and have improved the efficiency of our gene editing strategy. We also show that the strategy is effective in two additional mouse models, one representing acute infection in mouse cells and the other representing chronic, or latent, infection in human cells."

There are more than 100,000 people living with HIV in Britain and around 600 die each year.

Antiretroviral drugs are now very good at controlling infection but patients need to be on medication for life and if they stop taking treatment the virus replicates rapidly, eventually causing acquired immune deficiency syndrome, or AIDS.

The new technique - called Crispr/Cas9 - involves targeting the genetic code of HIV which inserts itself into cells.

Scientists take a protein called Cas9 and modify it so it can recognise viral code.

Blood is then extracted from the patient - or in this case a mouse - and the Cas9 protein added where it seeks out the HIV DNA in immune cells. Once it finds it, it releases an enzyme which removes the sequence, effectively snipping out the virus. The healthy modified cells would the be transfused back into the patient.

Scientists believe that replacing just 20 per cent of immune cells with the genetically altered cells would be enough to cure the disease.

The team are now hoping to move to trials in primates, and eventually humans, which could begin before 2020.

"The next stage would be to repeat the study in primates, a more suitable animal model where HIV infection induces disease, in order to further demonstrate elimination of HIV-1 DNA in latently infected T cells and other sanctuary sites for HIV-1, including brain cells,' said Prof Kamel Khalili, of the Department of Neuroscience at Lewis Katz.

"Our eventual goal is a clinical trial in human patients."

The research was published in the journal Molecular Therapy.

Telegraph.co.uk

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