Method of using peptides to enhance immune response has potential role in
fighting cancer and pandemic influenza
TORONTO, April 26 /PRNewswire-FirstCall/ -- Generex Biotechnology Corp.
(Nasdaq: GNBT) 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."
Among the academic papers detailing these techniques in vaccines for
cancer and infectious disease are:
- Kallinteris NL, Lu X, Wu S, Hu H, Li Y, Gulfo JV, Humphreys RE, Xu M.
Ii-Key/MHC class II epitope hybrid peptide vaccines for HIV. Vaccine
2003; 21:4128-32.
- Gillogly ME, Kallinteris NL, Xu M, Gulfo JV, Humphreys RE, Murray JL.
Ii-Key/HER-2/neu MHC class-II antigenic epitope vaccine peptide for
breast cancer. Cancer Immunology and Immunotherapy. 2004; 53:490-6.
- Kallinteris NL, Wu S, Lu X, von Hofe E, Humphreys RE, Xu M. Linkage of
Ii-Key segment to gp100(46-58) epitope enhances the production of
epitope-specific antibodies. Vaccine. 2005; 18:2336-8.
- Kallinteris NL, Wu S, Lu X, Humphreys RE, von Hofe E, Xu M. Enhanced
CD4+ T cell response in DR4-transgenic mice to a hybrid peptide
linking the Ii-Key segment of the invariant chain to the melanoma
gp100(46-58) MHC class II epitope. Journal of Immunotherapy, 2005, in
press.
About Generex
Generex is engaged in the research and development of drug delivery
systems and technologies. Generex has developed a proprietary platform
technology for the delivery of drugs into the human body through the oral
cavity (with no deposit in the lungs). The Company's proprietary liquid
formulations allow drugs typically administered by injection to be
absorbed into the body by the lining of the inner mouth using the Company's
proprietary RapidMist(TM) device. The Company's flagship product, oral insulin
(Oral-lyn(TM)), is in late stage clinical trials around the world. Generex
acquired Antigen Express in August. 2003. The core platform technologies of
Antigen Express comprise immunotherapeutics for the treatment of malignant,
infectious, allergic, and autoimmune diseases.
For more information, visit the Generex Web site at
http://www.generex.com.
Safe Harbor Statement: This release and oral statements made from time to
time by Generex representatives concerning the same subject matter may contain
"forward- looking statements" within the meaning of the Private Securities
Litigation Reform Act of 1995. These statements can be identified by
introductory words such as "expects," "plans," "intends," "believes," "will,"
"estimates," "forecasts," "projects" or words of similar meaning, and by the
fact that they do not relate strictly to historical or current facts. Forward-
looking statements frequently are used in discussing potential product
applications, potential collaborations, product development activities,
clinical studies, regulatory submissions and approvals, and similar operating
matters. Many factors may cause actual results to differ from forward-looking
statements, including inaccurate assumptions and a broad variety of risks and
uncertainties, some of which are known and others of which are not. Known
risks and uncertainties include those identified from time to time in the
reports filed by Generex with the Securities and Exchange Commission, which
should be considered together with any forward-looking statement. No
forward-looking statement is a guarantee of future results or events, and one
should avoid placing undue reliance on such statements. Generex claims the
protection of the safe harbor for forward-looking statements that is contained
in the Private Securities Litigation Reform Act.
SOURCE Generex Biotechnology Corporation
CONTACT: Shayne Gilliatt of Generex Biotechnology Corporation
1-800-391-6755, or 1-416-364-2551
Ed Lewis of CEOcast, Inc.
1-212-732-4300, or elewis@ceocast.com
for Generex Biotechnology Corporation
Web site: http://www.generex.com
04/26/2005 09:00 EDT http://www.prnewswire.com
