Peptide-based vaccine offers easy scale-up and flexibility in preparing for possible pandemic bird flu threat
Totonto-based Generex Biotechnology Corporation announced proposals for co-development of the Antigen Express novel H5N1 avian influenza vaccine in China.
The vaccine technology being employed at Antigen Express for the potentially pandemic avian influenza is the same as that for its novel immunotherapeutic cancer vaccine currently in clinical trials.
Antigen Express Inc, a wholly-owned immunotherapeutics subsidiary of Generex, arranged a trip to Beijing by its Vice-President of Biology, Dr. Minzhen Xu.
Proposals were made to: Professor Hualan Chen of the Harbin Veterinary Research Institute; Ms. Nan Wang, Vice General Manager of Sinovac Biotech Co., Ltd.; and Professor Bing Sun of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All have an interest in vaccine development for the H5N1 avian influenza in China.
Dr. Xu said “The basis of this technology lies in identifying portions of a specific disease-associated protein that are capable of stimulating T helper cells which are subsequently modified to augment their vaccine potency”.
T helper cells play a critical role in generating an immune response to a novel foreign agent, directing other immune cells against that threat, and in establishing immunological ‘memory’ of that agent. Once these cells are stimulated, it is much easier to mount an effective response against an agent such as the H5N1 influenza virus.
Antigen Express has existing collaborations in China focusing on SARS and a novel immunotherapy strategy for patients with acute myeloid leukemia. These relationships provide a convenient platform for expanding into avian influenza in China.
The danger posed by avian influenza in China is more acute, given the recent outbreaks of the H5N1 strain in birds there, and they face the same supply limitations on traditional vaccines as are faced throughout the world.
Vaccinating people close to hot spots of H5N1 outbreaks is recognized as the best way to control a possible pandemic.
Current estimates are that the world capacity pre year for production of H5N1 vaccine by traditional methods would protect less than 40 million people.
Scientists at Antigen Express are developing a vaccine for the potentially pandemic Asian bird flu utilizing highly conserved fragments of the H5 protein to stimulate potent T-helper cell activity. The H5 fragments are modified using a portion of an immunoregulatory protein (termed Ii-Key) that greatly facilitates their ability to stimulate T-helper cell responses specific to the H5N1 strain. The vaccine peptides have been selected for their likelihood of being both potent and active in more than 90% of the population.
This technology has the advantage of being applicable to any novel agent or protein once one has sequence information. As vaccine peptides are manufactured by entirely synthetic means they can be produced rapidly, relatively inexpensively, and in large quantities (hundreds of millions of doses).
Generex is engaged in the research and development of drug delivery systems and technologies. For more information, visit www.generex.com.
