U of A researchers move closer to discovering hepatitis vaccine

StephenW

EDMONTON - A University of Alberta research team is one step closer to discovering a vaccine for hepatitis C that appears to work against all the major strains of the disease.
Michael Houghton, a researcher at the Li Ka Shing Institute of Virology at the U of A, says his discovery was unexpected. That’s because there are six major strains of hepatitis C and hundreds more subtypes infecting 170 million people around the world. Hepatitis C is spread through contaminated blood and can be associated with needle-sharing, medical procedures involving unsterilized equipment, or blood transfusions.
Vaccines, made with the antibodies of specific strains, tend to only work against those specific disease types. Think, for instance, about the flu vaccine and how it covers only certain strains expected to circulate during a given flu season.
Houghton said new data from the U of A shows his vaccine, made from one strain of the hepatitis disease, produces antibodies that can neutralize all the hepatitis C types around the world.
“I think that’s great news for our efforts to develop a vaccine for hepatitis C,” said Houghton, a world-renowned expert in medical microbiology and immunology who discovered the hepatitis C virus in 1989. He presented his recent findings during Wednesday’s Canada Excellence Research Chairs Summit in Vancouver. “It’s a very unexpected result and it’s guiding us toward the development of a successful hepatitis vaccine.”
Such a vaccine was thought impossible and impractical, since hepatitis C is more heterogeneous — or has more varieties — than HIV.
“In the HIV field, for example, it’s been the Holy Grail for many years to try to elicit antibodies that can neutralize all the different types around the world,” Houghton said. He, then, has potentially discovered the Holy Grail for hepatitis C.
“I think it’s a very big step forward,” he said. “I’ve been working on the vaccine for 15 years (and) for so many years, the field felt that antibodies would be very restricted in their neutralizing ability, that you could only neutralize the same strain that the vaccine was derived from.”
His lab study defied that belief.
“It’s very encouraging that we can do it and really gives us a hope that an effective vaccine can be produced for hep C.”
John Law, Houghton’s research partner, said preliminary tests showed the vaccine blocked some strains from entering a person better than others, with success rates ranging from 40 per cent to 100 per cent. He said the effectiveness could be improved in clinical trials by playing with the dosage.
Houghton said while it would take five to seven years before such a vaccine could hit the market — it must be proven safe and effective in large clinical trials involving humans — he said the vaccine could also help those already infected with the disease. Of the millions who carry the infection, up to 20 per cent develop chronic illness, including cirrhosis of the liver.
A drug cocktail already on the market cures 70 per cent of those infected with hepatitis C, Houghton said. He said further research needs to determine if a combination of that antiviral with the new vaccine could increase the success rate.
“It may also be beneficial as a therapeutic vaccine,” he said. “That does deserve attention in the future.”
Dr. Lorne Tyrrell, a hepatitis expert and the Canadian Institutes of Health Research and GlaxoSmithKline chair in virology at the U of A, said if the vaccine proves effective, it will have a global impact. In Egypt, for instance, 10 per cent of the population carries hepatitis C.
“In many parts of the world, the antiviral therapy we currently have for hepatitis C is often out of the reach of most people’s affordability so having a (cheaper) vaccine that could be used to prevent the disease in those countries is particularly important,” Tyrrell said.
“There’s still a lot of work that needs to be done, but at least it’s a clue and an indication that we can develop a potential vaccine for hepatitis C.”
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StephenW

埃德蒙顿 - 艾伯塔大学的研究小组发现C型肝炎的疫苗，似乎对所有疾病的主要株更接近了一步。

迈克尔·霍顿，在一个U李嘉诚病毒学研究所的研究员说，他的发现是意外。这是因为有六大株丙型肝炎和数百个亚型感染170万世界各地的人们。丙型肝炎是通过受污染的血液传播，并可以共用针头，医疗涉及未经消毒设备的程序，或输血。

疫苗，用特定菌株的抗体，往往只针对这些特定疾病类型。想想看，例如，有关流感疫苗，它涵盖了如何预计在一个给定的流感季节循环的某些菌株。

霍顿说，新的数据显示，从一个U肝炎疾病的应变之一，他的疫苗，产生抗体，能中和世界各地的所有丙型肝炎类型。

“我认为这是对我们的努力，开发出C型肝炎疫苗的好消息，”霍顿说，在医学微生物学和免疫学的世界知名专家，在1989年发现C型肝炎病毒。周三加拿大卓越研究主席在温哥华举行首脑会议期间，他提出了他最近的调查结果。 “这是一个非常意外的结果，它引导我们走向一个成功的肝炎疫苗的发展。”

这种疫苗被认为不可能的，不切实际的，因为C型肝炎是更多的异构 - 或有更多的品种 - 比HIV。

“在艾滋病领域，例如，它多年来一直的尝试引起的抗体能中和世界各地的各种不同类型的圣杯，”霍顿说。 ，那么，他有可能发现C型肝炎的圣杯

“我认为这是一个非常大的一步，”他说。 “我已经工作这么多年，15年（和）疫苗领域认为，抗体将会受到很大限制，在他们的中和能力，你只能抵消该疫苗是来自同一菌株。”

他的实验室研究无视这一信念。

“这是非常令人鼓舞的，我们能做到这一点，真正为我们提供了一种有效的疫苗可以为HEP C.生产的希望”

霍顿的研究合作伙伴，法，约翰说，初步试验表明疫苗阻断进入一个人比别人更好的成功率从40％至100％不等，一些菌株。他说，改善临床试验的有效性，可以打剂量。

霍顿说，同时将采取5至7年之前，这种疫苗可以打市场 - 它必须在涉及人类的大规模临床试验证明安全有效 - 他说，疫苗也可以帮助那些已经感染此病。数以百万计人进行感染，高达20％发展成慢性疾病，包括肝硬化。

霍顿说，已经与丙型肝炎病毒感染者的百分之70％的市场治愈的药物鸡尾酒。他说，进一步的研究需要确定的新疫苗，抗病毒药物相结合，如果能提高成功率。

“作为治疗性疫苗，这也可能是有益的，”他说。 “这确实值得在未来的关注。”

和一个U型肝炎专家加拿大健康研究和葛兰素史克公司的椅子病毒学研究所，洛恩泰瑞尔，博士说，如果疫苗被证明是有效的，它将有一个全球性的影响。例如，在埃及，10％的人口携带丙型肝炎

“在世界许多地方，在抗病毒药物治疗，我们目前C型肝炎有经常出大多数人的负担能力的覆盖范围，使1（便宜）的疫苗，可以被使用，以防止这些国家疾病是特别重要的，”泰瑞尔说。

“还有很多工作需要做，但它至少是一个线索和迹象表明，我们可以开发出C型肝炎疫苗”

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