PeptoSomes for Vaccination: Combining Antigen and Adjuvant in Polypept(o)ide-Based Polymersomes

Area of Science:

• Biotechnology
• Nanotechnology
• Immunology

Background:

• PeptoSomes are novel polypept(o)ide-based polymersomes.
• They are constructed from polysarcosine (PSar) and poly(benzyl-glutamic acid) (PGlu(OBn)) block-copolymers.
• Controlled ring-opening polymerization yields polypept(o)ides with a low dispersity index (1.32).

Purpose of the Study:

• To report the first vaccine based on PeptoSomes.
• To investigate the potential of PeptoSomes as a versatile vaccination platform.
• To evaluate the delivery of antigen (SIINFEKL) and adjuvant (CpG) into dendritic cells (DCs).

Main Methods:

• PeptoSome synthesis via controlled ring-opening polymerization.
• Vesicle formation using dual centrifugation technique.
• Characterization using multiangle dynamic light scattering, static light scattering, and cryoTEM.
• Evaluation of cellular uptake and immune stimulation in dendritic cells.

Main Results:

• PeptoSomes were successfully synthesized and characterized with a hydrodynamic radius of 39.2 nm and low dispersity (µ₂ = 0.1).
• Dual centrifugation enabled high loading efficiency (up to 40 mol%).
• Loaded PeptoSomes effectively delivered antigen and adjuvant to DCs, stimulating activation (CD80, CD86, MHCII expression) and cytokine release (TNFα).
• PeptoSomes induced antigen-specific T-cell proliferation.

Conclusions:

• PeptoSomes represent a promising new platform for vaccine development.
• Simultaneous delivery of antigen and adjuvant by PeptoSomes enhances immune cell activation.
• This technology demonstrates significant potential for effective vaccination strategies.