U of S Researchers Develop New Vaccine Candidate Against Hepatitis C

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U of S Researchers Develop New Vaccine Candidate Against

Hepatitis C

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 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.

" This technique uses the body's own cells, called dendritic cells, to

vaccinate against hepatitis C, " said Dr. 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 for 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. "

The VIDO vaccine uses a viral protein that is common among different

strains, ensuring that the vaccine will be effective against them.

The researchers exposed dendritic cells in vitro to a HCV protein.

The cells

were also exposed to a strong immune stimulator to increase the

immune

response and then injected into mice as a vaccine. Because HCV does

not

infect mice, mice were challenged with a carrier virus containing the

hepatitis C protein. The levels of HCV protein in immunized mice

using this

model were five orders of magnitude lower than the control.

Co-authors on the study include Hong Yu, a post-doctoral fellow at

VIDO and

recipient of a National Canadian Research Training Program in

Hepatitis C

post-doctoral fellowship award, and VIDO director Lorne Babiuk. Hui

Huang

and Jim Xiang are members of the Saskatchewan Cancer Agency.

VIDO is recognized by the scientific community as a world leader in

RandD

and commercialization of vaccines and novel formulation and delivery

systems

for livestock and human diseases. VIDO is a financially self-reliant,

non-profit organization owned by the U of Sand operates with

substantial

support from the Government of Canada and the governments of Alberta

and

Saskatchewan, as well as industry competitive grants.

The CIHR is the Government of Canada's agency for health research.

CIHR's

mission is to create new scientific knowledge and to catalyze its

translation into improved health, more effective health services and

products, and a strengthened Canadian health care system. Composed of

13

institutes, CIHR provides leadership and support to close to 10,000

health

researchers and trainees across Canada.