Mymetics' HIV Vaccine Demonstrates First-Ever Production of Neutralizing IgA Antibodies in Non-Human Primate Model
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- Category: Vaccines
- Published on Friday, 08 June 2007 04:00
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NYON, Switzerland | June 7, 2007 | MymeticsCorporation (Nasdaq: MYMX.PK) announced today analysis of resultsdemonstrating that the Company's HIV vaccine elicited neutralizing IgAmucosal antibodies in a non-human primate model. Mucosal IgA antibodies areconsidered as a possible first line of defense against infection by HIV.The data were presented by Sylvain Fleury, Ph.D., Mymetics' ChiefScientific Officer, in an oral presentation titled, "Without MucosalAdjuvant, Virosomes-gp41 Peptides from the MPR can Elicit ProtectiveMucosal IgA in Vaccinated Macaques," at the recent Keystone Symposium, HIVVaccines: From Basic Research to Clinical Trials.
According to the findings, more than 90 percent of non-human primatesvaccinated with virosomes expressing the HIV-1 gp41 peptide producedmucosal IgA antibodies in the genital and intestinal compartments. Thesemucosal antibodies were capable of preventing HIV transcytosis, a processby which HIV crosses the membrane epithelium of the mucosa, by 60 to 98percent. When total IgA was purified for testing in standard neutralizingassays (TZMbl), the IgA antibodies also showed the ability to neutralize aprimary HIV clade B virus (QH0692) known to be difficult to neutralize.Mucosal IgA produced against the HIV gp41 protein after vaccination wasdetermined to be as good or better than the best anti-HIV neutralizingmonoclonal antibodies (2F5, 4E10 and b12) currently on the market, whencomparing the amount of antibodies required for neutralizing 50 percent ofthe viruses.
Mymetics' Dr. Fleury commented, "These results are extremelyencouraging. We believe that, by using virosomes which target the mucosalcompartment, we now have a means to elicit neutralizing IgA that canpotentially work at low concentrations. Furthermore, virosomes do notrequire a mucosal adjuvant for triggering mucosal antibodies. This may cutthe time to market since mucosal adjuvants are not currently marketed forhuman use."
Dr. Fleury added, "Mymetics and its collaborators are the first groupto report neutralizing IgA obtained after vaccination against HIV innon-human primates. In the coming year, Mymetics intends to conduct anotherstudy in non-human primates for testing of an improved vaccine version.Pending positive results, we may be able to file to initiate a clinicaltrial and begin phase I testing some time in late 2008."
Mymetics Vaccine Program Background
Worldwide, over 85 percent of HIV infections are the result of sexualtransmission in which mucosal tissues from the genital and anorectalregions have been exposed to HIV-1 present in semen or secretions.According to a recent report from the International AIDS VaccineInitiative, "Since an effective preventive AIDS vaccine will primarily haveto protect an individual from sexual transmission of HIV, researchers thinkit will probably be important for a vaccine candidate to induce strongmucosal immune responses." Mymetics-affiliated researchers have been ableto engineer gp41-derived antigens (proteins and peptides) capable ofeliciting antibodies, particularly IgA antibodies, with strong potentialfor preventing in vitro virus translocation across the mucosal barrierand/or to inhibit cell infection, thus preventing HIV-1 infection.
Mymetics has combined three important concepts in its vaccine design:
-- Induction of mucosal and blood antibodies to allow protection in different anatomical compartments and block the early event of HIV translocation at the genito-reproductive and intestine tracts and subsequent infection of target cells underlying the mucosal tissues, thereby preventing HIV entry and spreading in the body.
-- Focusing the immune response against conserved regions on gp41 that may induce protective antibodies against a broad range of HIV clades. Mymetics is developing vaccines that contain antigens expressing limited immunodominant regions, while immunodistractive regions have been removed or altered without affecting the immunogenicity of the antigen.
-- Minimal mimicry. This aspect is important when dealing with HIV proteins that have several known homologies with human proteins. Developing antibodies against such native HIV proteins may lead to cross-reactions toward human proteins and, consequently, increased risk of developing potential long-term autoimmunity side effects after vaccination with unmodified HIV proteins. Mymetics' concept is to use a small engineered HIV protein sequence (gp41) that has been mostly deleted of its human protein homologies. This innovative concept is expected to render the vaccine effective against HIV while providing a safer alternative to other vaccine approaches.
About Mymetics
Mymetics was founded in 1990 near Lyon, France and was registered as aUS (Delaware) public company in 2000. Since August 2003, its operations andresearch programs have been managed out of Switzerland (Nyon, near Geneva).
Mymetics Common shares trade on NASDAQ's OTC:PK under the symbol MYMX.For more information, please visit the Company's website athttp://www.mymetics.com/.
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SOURCE: Mymetics Corporation