New HIV-Mimicking Particles That Trigger Immune Response Could Advance AIDS Vaccine Design
May 19, 2016 - New York - Call it a sheep in wolf's clothing. Researchers with the International Aids Vaccine Initiative (IAVI) and The Scripps Research Institute (TSRI) have built tiny particles that resemble HIV on their outside and used them to provoke an immune response in animals. Their work, which was published today in the journal Cell Reports, could advance the design of an effective AIDS vaccine.
The researchers successfully produced synthetic nanoparticles (liposomes) that they decorated with protein components (trimer spikes), that protrude from HIV-1's outer membrane (the viral envelope). These protein components are normally used by the virus to grab onto the human cells it then goes on to infect.
HIV has roughly a dozen of the trimer spikes on its envelope surface. In contrast, the synthetic nanoparticle is decorated with several hundred spikes that mimic the native trimers. “We built the nanoparticle envelope with this many spikes because we thought it would offer a real advantage to trigger a more effective immune response by offering the immune system more binding sites ,” said Richard Wyatt, the senior author of the study and an immunology professor at IAVI's Neutralizing Antibody Center at TSRI.
“It turns out that this was indeed the case. We've found that the trimer-liposomes better elicits an immune response than trimers that are not packaged on such particles. This establishes our technique as a potential first step toward a more broadly effective vaccine against HIV,” said Jidnyasa Ingale the lead author and Research Associate at TSRI.
The researchers tested the trimer-containing particles in mice and rabbits, finding that it successfully and efficiently provoked the immune system to respond. Specifically, the particles activated B cells, a white blood cell that can produce broadly neutralizing antibodies, which, in laboratory tests, have shown that they are able to neutralize a broad spectrum of the many HIV-1 variants that circulate globally. HIV-1 is the most widespread HIV type worldwide.
The researchers say their early success doesn't just hold opportunity for HIV. The approach of building synthetic pathogen mimics could possibly be used to make vaccines against other types of viruses, as well.
The International AIDS Vaccine Initiative (IAVI) is a global not-for-profit organization whose mission is to ensure the development of safe, effective, accessible, preventive HIV vaccines for use throughout the world. Founded in 1996, IAVI works with partners in 25 countries to research, design and develop AIDS vaccine candidates. The organization also conducts policy analysis and serves as an advocate for the AIDS vaccine field. It supports a comprehensive approach to addressing HIV and AIDS that balances the expansion and strengthening of existing HIV prevention and treatment programs with targeted investments in the design and development of new tools to prevent HIV. IAVI is dedicated to ensuring that a future AIDS vaccine will be available and accessible to all who need it. The organization relies on the generous donations of governments, private individuals, corporations and foundations to carry out its mission.
Integral to IAVI's mission is ensuring that future HIV vaccines meet the needs of people who live where HIV/AIDS hits the hardest. IAVI also works closely with many Clinical Research Center (CRC) partners to build sustainable research and development capacity in the communities and countries that participate in vaccine research. www.iavi.org
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Source: IAVI International AIDS Vaccine Initiative
Reproduced with permission - "International AIDS Vaccine Initiative (IAVI)"
International AIDS Vaccine Initiative (IAVI)
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