Stem Cells to fight HIV?

Researchers are studying a new approach that arms the immune system with
an intrinsic defence against HIV.

While speaking at the Society for General Microbiology's spring meeting in
Edinburgh, Professor Ben Berkhout explained how this new approach could
dramatically improve the quality of life and life expectancy for HIV
sufferers in whom antiviral drugs are no longer effective.

In the absence of an effective vaccine, daily administration of
anti-retroviral drugs is the most effective treatment for HIV. However,
low patient compliance rates combined with the virus's ability to easily
mutate has led to the emergence of drug-resistant strains that are
difficult to treat.

Professor Berkhout from the University of Amsterdam is investigating a
novel gene therapy that has long-lasting effects even after a single
treatment. It involves delivering antiviral DNA to the patients' own
immune cells that arms them against viral infection. "This therapy would
offer an alternative for HIV-infected patients that can no longer be
treated with regular antivirals," he suggested.

The therapy involves extracting and purifying blood stem cells from the
patient's bone marrow. Antiviral DNA is transferred to the cells in the
laboratory, after which the cells are re-injected into the body. The DNA
encodes tiny molecules called small RNAs that are the mirror image of key
viral genes used by HIV to cause disease. The small RNAs float around
inside the immune cell until they encounter viral genes which they can
stick to like Velcro(tm). This mechanism, called 'RNA interference' can
block the production of key viral components from these genes.

Transferring the antiviral DNA to stem cells would help to restore a large
part of the patient's immune system. "Stem cells are the continually
dividing 'master copy' cells from which all other immune cells are
derived. By engineering the stem cells, the antiviral DNA is inherited by
all the immune cells that are born from it," explained Professor Berkhout.