VIDO targets world's first vaccine for Hepatitis C

Feb 4, 2003

A new research project is targeting a vaccine for Hepatitis C – an infectious and often fatal virus carried by 175 million people worldwide. The project is conducted by the Veterinary Infectious Disease Organization (VIDO) in Saskatoon, with support from the Canadian Network for Vaccines and Immunotherapeutics.

Developing a vaccine for Hepatitis C has proven a tremendous challenge for researchers worldwide, says lead scientist Dr. Sylvia Van den Hurk. But VIDO's use of innovative DNA vaccine technology and large animal models offers a unique and promising approach.

"Most vaccine development efforts have focused on traditional vaccines, which involve injecting an organism into the body to induce a systemic immune response," explains Van den Hurk. "However, this is typically not strong enough to induce an immune response at the cellular level, which is now thought to be crucial in battling the Hepatitis C virus. DNA-based vaccination is a relatively new technology that has shown the ability to induce a much stronger cellular immune response."

Four out of five people infected with Hepatitis C develop a chronic form of the disease. But for the one in five that clear the infection, the difference appears to be a powerful cellular immune response, says Van den Hurk. "This is where DNA vaccines have tremendous potential."

DNA vaccines consist of a circular piece of DNA, which contains an immunity-inducing gene. Once the DNA is safely inside the cell of an animal, it produces a protein that generates an immune response. An additional approach VIDO is pursuing is to combine a vaccine protein with "CpG" oligodeoxynucleotides (ODN) for an even stronger immune response, says Van den Hurk. "CpGs" are a type of bacterial DNA that elevates the body's normal disease resistance.

In addition to the prevention of Hepatitis C, DNA vaccines may also hold therapeutic potential for the disease, she says. "A strong enough cellular immune response may reduce the virus load in those already chronically infected with Hepatitis C, opening the door to a wave of new therapeutic vaccines."

VIDO has been at the forefront of DNA vaccine technology the past several years through its work on food animal infectious diseases. This, along with VIDO's long-standing work in developing large animal models for vaccine formulation and development, led to the Hepatitis C project.

"Our large animal models are based on years of research data," she says. "They allow us to examine how to deliver vaccines effectively and induce an immune response in a particular animal species. Similarities between some animal species and humans allow us to predict the human impact. For Hepatitis C, we're using our swine model because pigs have an immune system, size and skin similar to that of humans."

VIDO is a world leader in vaccine research for the control of infectious diseases in food animals and poultry and is a wholly owned University of Saskatchewan not-for-profit institute. It operates with substantial support from the Government of Alberta and the Government of Saskatchewan as well as Government of Canada competitive grants.