TB vaccine made more effective
Scientists claim to have unravelled one of clinical medicine’s enduring mysteries on the waning resistance of the tuberculosis vaccine and in the process developed a stronger antidote for the disease.
“Our findings represent nearly a 180-degree reversal from the dogma of the last 60 years -- that the TB vaccine stopped working because it became over-attenuated and was too ’wimpy’ to be effective,” said Douglas Kernodle, ass
ociate professor of Medicine at the Vanderbilt University Medical Centre, US.
Kernodle and his team, including research instructor Lakshmi Sadagopal, found that the TB vaccine has acquired some traits that make it less effective in evoking sustained immune response.
However, when these traits were removed from the TB vaccine, it induced stronger immune responses in mice, the researchers found.
The current TB vaccine, known as BCG, has been in use since 1920s.
It was developed by weakening (attenuating) a strain of bacteria that causes TB in cows, which is genetically 98 per cent identical to the human TB germ.
“Our research targeted genetic duplications that actually make the BCG vaccine immune-evasive as infected cells in the body produce oxidants to destroy harmful bacteria,” Sadagopal told PTI in an email interview. — PTI
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