Apr 26 2005
Generex Biotechnology announced today that its wholly owned subsidiary, Antigen Express, has received Australian Patent No. 778115 titled "Hybrid Peptides Modulate the Immune Response." Antigen Express is designing and testing such vaccine peptides for the control of cancer and infectious diseases with a particular focus on the pandemic H5N1 influenza, which has been reported in South East Asia.
The specific award covers the use of vaccine peptides composed of the immunoregulatory Ii-Key peptide joined through a simple chemical spacer to MHC class II epitope peptides. Such hybrid peptides have about 200 times greater potency in vitro than the epitope-only peptide. In mouse vaccine experiments, such hybrids induce four-to-eight times greater T helper cell responses, when measured by special T helper cell assays.
A priority program for Generex and Antigen Express is the development of a vaccine using this technology to protect against pandemic H5N1 influenza. The Antigen Express vaccine could be used to prime T helper cell responses to a recombinant protein of H5 hemaglutinin. Such priming might be mandatory if recombinant H5 protein is in short supply, as some fear. Alternatively, the Antigen Express vaccine might be useful as a stand-alone vaccine if the pandemic progresses too swiftly.
The World Health Organization has warned that the H5N1 influenza might kill millions of persons worldwide, but vaccines against it cannot be easily raised because the virus is so strong that it kills the chicken embryos inside eggs in which vaccines are usually prepared. The current vaccine for the prevalent flu strains consists basically of H1 and H3 hemagglutinin proteins isolated from such inoculated eggs.
Development of the influenza H5 vaccine is being coordinated by Dr. Douglas Powell, Director of Immunobiology at Antigen Express. Powell trained at the National Institutes of Health with Dr. Tony Fauci and was a postdoctoral fellowship at the Gladstone Institute of Virology at University of California, San Francisco, with Dr. Warner Greene. He worked previously at DuPont Merck Pharmaceutical Co., and most recently was Project Leader in Virology at Millennium Pharmaceuticals Inc., working to identify novel T cellular targets for therapeutic intervention in HIV/AIDS.
Dr. Powell said, "I am optimistic that we have achieved a breakthrough in methods to prime a potent T cell response to individual MHC class II epitopes for various infectious diseases. In addition to protecting against pandemic influenza, I believe that similar experiments we are now pursuing with MHC class II epitopes from HIV gag and nef will lead to immunotherapeutic vaccines to protect against disease progression in HIV-positive individuals."