Mucosal IgA antibodies are considered as a possible first line of defense against infection by HIV, according to Mymetics. The results demonstrated that more than 90% of non-human primates vaccinated with virosomes expressing the HIV-1 gp41 peptide produced mucosal IgA antibodies in the genital and intestinal compartments. These mucosal antibodies were capable of preventing HIV transcytosis, a process by which HIV crosses the membrane epithelium of the mucosa, by 60 to 98%.
When total IgA was purified for testing in standard neutralizing assays, the IgA antibodies also showed the ability to neutralize a primary HIV clade B virus known to be difficult to neutralize. Mucosal IgA produced against the HIV gp41 protein after vaccination was determined to be as good or better than the best anti-HIV neutralizing monoclonal antibodies currently on the market, when comparing the amount of antibodies required for neutralizing 50% of the viruses, the company claimed.
Sylvain Fleury, Mymetics’ chief scientific officer, said: “Mymetics and its collaborators are the first group to report neutralizing IgA obtained after vaccination against HIV in non-human primates. In the coming year, Mymetics intends to conduct another study in non-human primates for testing of an improved vaccine version. Pending positive results, we may be able to file to initiate a clinical trial and begin phase I testing some time in late 2008.”