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Nanoparticles to fight against AIDS

​The CEA has developed an immunization approach against HIV, based on a new delivery system, lipid nanoparticles Lipidots. Lipidots transport and deliver the viral protein, p24, essential antigen in HIV vaccines, combined with the CpG, an immunostimulatory agent. This system enhances the immune response to the protein and possibly the effectiveness of a future vaccine using this technology.

Published on 6 March 2019

​According to UNAIDS statistics, since the first HIV cases were discovered, more than 35 years ago, 78 million people have been infected with HIV and 35 million have died of the virus. The CEA is involved in the research and development of therapeutic and preventive approaches in the fields of infectious diseases, including AIDS.

Carry the medicine in the body as close as possible to the cells to be treated

In 2006, as part of a collaboration with the CNRS, CEA-Leti, CEA's research and technological center specialized in micro and nanotechnologies, has developed Lipidots, nanoparticles based on oil and wax. Lipidots is a versatile nano-delivery platform that encapsulates drugs and/or imaging agents in tiny droplets of oil and delivers them to targeted cells in the body for patient treatment or diagnosis. The small size of the Lipidots NLCs, approximately 100nm in diameter, allows them to enter the body's lymphatic vessels, which carry them to the lymph nodes where they trigger a stronger immune response.

Strengthened immune responses

Until now, p24-based vaccines have shown limited effectiveness because of an insufficient immune response to this antigen in HIV patients. Based on its Lipidots® delivery platform, CEA's new approach improves immunogenicity against the p24 HIV protein by loading it and an immunostimulant agent onto nanostructured lipid carriers (NLCs). This may be a first step for a new HIV vaccine that also would include additional components of the virus.

"Despite a major effort by the scientific community to develop HIV vaccines, the virus continues to infect people every day," said Fabrice Navarro, head of CEA-Leti's Microfluidic Systems and Bio-Engineering Lab. "Vaccine candidates face immunological obstacles that can be overcome only by introducing innovations in the design of vaccine formulations."

In the article, CEA demonstrated that with mice and non-human primates this new approach significantly enhanced immune responses against p24 by increasing specific antibody production and T-cell activation, when associated with Lipidots NLCs delivering the CpG immunostimulant. Indeed, the lipid carriers are able to protect the CpG nucleic acids from the extracellular environment and to deliver it intracellularly directly into the dendritic cells, the antigen-presenting cells that mediate the induced immune responses.

CEA-Leti's research partners on this study also include IDMIT and IAB-INSERM U1209.