New vaccine candidate developed for hepatitis C
By Tess Laidlaw
Researchers at the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO) have developed a vaccine candidate for hepatitis C, leading to hope in the fight against a disease for which no vaccines are yet available.
VIDO is the first in Canada to show that this vaccination technique may be effective against HCV. The study was published in this month’s Journal of General Virology.
The research team, funded by the Canadian Institutes of Health Research (CIHR) and the Canadian Network for Vaccines and Immunotherapeutics (CANVAC), produced a vaccine candidate that decreased the amount of a carrier virus expressing hepatitis C virus (HCV) protein in mice by 100,000 times compared to the control group.
“This technique uses the body’s own cells, called dendritic cells, to vaccinate against hepatitis C,” said Bhagirath Singh, Scientific Director of the CIHR Institute of Infection and Immunity.
Dendritic cells are key components of the immune system, activating and shaping the immune response. “The vaccine reduced the amount of hepatitis C protein in a highly significant manner,” he said. “This offers a very promising approach to prevent liver disease caused by the virus and to ultimately eliminate it from the body.”
About 20 per cent of people who contract HCV overcome the virus on their own. For those who develop chronic hepatitis, the immune system cannot clear the infection.
“In patients with chronic hepatitis C, there is evidence that the function of their dendritic cells is altered,” said Sylvia van den Hurk, senior VIDO scientist and member of the research team that developed the vaccine candidate.
“We thought that if we could ‘teach’ the dendritic cells how to properly activate the immune response and deliver them back to the patient as a vaccine, the patients would clear or at least control the infection.”
HCV is the leading cause of liver transplants in the western world, and its annual death toll is expected to triple in the next 10 years. Worldwide, there are about five times more people infected by HCV than with the HIV virus. Treatment of hepatitis C, which like HIV is spread by blood-to-blood contact, is costly and ineffective in about half the patients.
Researchers working in this field have a tough job, says van den Hurk. “The hepatitis C virus is always mutating. For example, one patient can be infected with a strain that spawns sub-strains with different sequences. They are all present at the same time, in the same patient.”
Co-authors on the study include Hong Yu, a post-doctoral fellow at VIDO and VIDO Director Lorne Babiuk. Hui Huang and Jim Xiang are members of the Saskatchewan Cancer Agency.