DNA vaccine prevents TB recurrence
Reactivation of dormant tuberculosis bacteria can be prevented by combining drug treatment with a DNA vaccine, new research suggests.
Scientists from South Korea infected mice with Mycobacterium tuberculosis and then treated them with the anti-tuberculosis drugs isoniazid and
pyrazinamide. In addition to the drugs, one group of mice received a
DNA vaccine composed of two different genes, Ag85A and PstS-3.
Following the drug therapy, no bacteria were detected in either group
of mice. However, M tuberculosis often lies dormant in host cells and
a relapse of the disease can occur years later either by reactivation
of the initial infection or by entry of a secondary infection.
After four weeks of treatment with dexamethasone, reactivation of the
disease was seen in 60 per cent of the mice who had not received the
vaccine, but no bacteria were detected in the mice who had received the
vaccine. The scientists also found that the vaccinated mice were less
susceptible to reinfection from a secondary source of the disease.
They conclude that combining multigene DNA vaccination with drug therapy
could be an effective strategy to prevent reactivation of the disease,
as well as minimising use of anti-tuberculosis drugs. This will limit
their cost and toxicity.
The study was published in an early online edition of Gene Therapy |
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Pharmaceutical Journal
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