Design and Functional Characterization of HIV-1 Envelope Protein-Coupled T Helper Liposomes

Area of Science:

• Immunology
• Vaccine Development
• Nanotechnology

Background:

• Functionalizing HIV-1 virus-like particle (VLP) vaccines with T helper epitopes can enhance immune responses.
• Liposomal platforms offer a GMP-scalable alternative to VLP-based vaccines for HIV vaccine development.

Purpose of the Study:

• To design and analyze customizable HIV envelope trimer (Env)-conjugated T helper liposomes.
• To evaluate the immunogenicity and potential of these liposomes as an alternative to T helper VLPs for HIV vaccines.

Main Methods:

• Passive encapsulation of T helper peptides into Env-trimer displaying liposomes.
• Quantitative improvement of peptide encapsulation using an anionic lipid formulation.
• Covalent coupling of uncleaved prefusion optimized (UFO) Env trimers to liposomes.
• Immunogold staining, FACS, and electron microscopy for characterizing Env trimer conformation and density.
• Intramuscular immunization of mice to assess in vivo antigen presentation by dendritic cells (DCs).

Main Results:

• Env-liposome conjugates activated Env-specific B cells and induced CD4+ T cell proliferation.
• Anionic liposomes improved peptide encapsulation efficiency.
• Liposome-delivered peptides were presented by DCs in secondary lymphoid organs post-immunization.
• Anionic Env-coupled T helper liposomes induced Env-specific B cell activation and proliferation comparable to T helper VLPs.

Conclusions:

• Customizable Env-conjugated T helper liposomes are a viable and GMP-scalable alternative to T helper VLPs for HIV vaccine applications.
• The nanoparticle characterization methods are applicable to other synthetic nanoparticle systems for pathogen-derived antigens.