may lead to a hepatitis C vaccine
Australia have discovered an antibody that has helped some people
develop immunity against hepatitis C, and they hope to use the discovery
as the foundation for an HCV vaccine, Agence France-Presse reports. The
study of 160 inmates showed that four Australian prisoners had built up
a natural immunity to HCV despite repeated exposures to the virus
through injection-drug use. Blood tests showed that even when infected
with the virus, the prisoners quickly cleared all HCV from their bodies.
A separate study of visitors to a Sydney drop-in center for
injection-drug users confirmed the researchers' findings.
"It seems that the higher the risk behavior, the greater the likelihood
the immunity would be present," lead researcher Andrew Lloyd of the
University of New South Wales told Agence France-Presse. "I suspect it
has something to do with the circumstances of the first exposure. It may
be that it was a very low dose that gets into the body and pushes the
balance in favor of an immune response."
The researchers say a build-up of a naturally occurring antibody that
can cripple the virus causes the immunity. Lloyd says his group's
findings appear to be similar to those of a study of Kenyan sex workers
repeatedly exposed to HIV, but who were able to avoid contracting the
disease. Lloyd says his team and other scientists are now working on
artificially replicating the naturally occurring antibody for use in a
possible vaccine to prevent HCV infection.
The full study appears in the August Journal of Infectious Diseases.