Reuters (01.04.12) - Friday, January 06, 2012
In a human trial, an experimental hepatitis C virus vaccine
generated immune responses similar to those seen in people who
have a rare natural defense against the disease, British and
Italian researchers said Wednesday. Forty-one healthy adults
participated in the Phase I trial, which suggested the vaccine
is safe and is able to stimulate a large T-cell response
against HCV that lasts for at least a year.
"The immune responses we've seen are exciting, and we are
beginning the next stage of trials. It could be a long road,"
said lead study author Paul Klenerman of Oxford University.
UK researchers from Oxford and Birmingham universities worked
with the Italian biotech firm Okairos to develop a vaccine
that stimulates a different part of the immune system from
those tried before. The vaccine candidate is designed to
generate a T-cell response to internal parts of HCV, which are
more constant, rather than an antibody attack on HCV's ever-
changing outer coat.
"The outside shell of [HCV] is very variable but the inside of
the virus is much more stable," Klenerman said. "That's where
the engine of the virus is, where we may be able to
successfully target many of the crucial pieces of machinery."
A US team is planning a larger trial among at-risk groups to
see if the vaccine can help prevent infection. Oxford
researchers are starting trials to examine whether it can help
people already infected with HCV, as well as working on
provoking better immune responses.
"T-cell responses often become weak in those with chronic
[HCV] infections," Klenerman said. "It may be that using a
vaccine to boost their immunity could become part of any
treatment with other drugs."
The study, "Novel Adenovirus-Based Vaccines Induce Broad and
Sustained T Cell Responses to HCV in Man," was published in
Science Translational Medicine (2012;4(115):115ra1).