March 11, 2013
Washington University School of Medicine researchers describe the bee venom toxin melittin as a promising HIV prevention and treatment measure, because melittin can disrupt the protective double-layered membrane surrounding the HIV virus. In laboratory studies, scientists loaded melittin onto nanoparticles and then added protective bumpers that cause the nanoparticles to bounce off normal cells, which tend to be much larger. The HIV virus, which is much smaller than nanoparticles, slips between the nanoparticle bumpers and comes into direct contact with melittin. The bee venom then fuses with the HIV viral envelope, ruptures it, and strips the vital structure from the virus. Thus, the melittin prevents HIV infection.
The research team is exploring two possible therapies based on the melittin-loaded nanoparticles: a vaginal gel to prevent HIV infection, and therapy for existing HIV infections. Research Instructor Joshua L. Hood, M.D., Ph.D., said the vaginal gel could help couples in which one person is HIV-infected and the other is not, when the couple wants to have a baby, because the nanoparticles are safe for vaginal cells and sperm. Other HIV therapies aim to disrupt virus replication in HIV-infected people, but some HIV strains have been able to reproduce in spite of the anti-replication therapies.
Hood said the nanoparticles were originally developed as an "artificial blood product," but nanoparticles were not effective in delivering oxygen. However, the nanoparticles circulate well and safely through the body and provide an adaptable "platform" for delivering therapies for HIV and other infections. Since melittin attacks double-layered membranes indiscriminately, it also could be useful in treating viruses like hepatitis B and C.
The full report, "Cytolytic Nanoparticles Attenuate HIV-1 Infectivity," was published online in the journal Antiviral Therapy (2012; doi: 10.3851/IMP2346).