Nanoparticles as a platform for the development of vaccines

DRA lecture held by Professor Miriam Breunig, University Regensburg, Germany

A potent vaccine induces long-lasting – in an ideal case lifelong – protection against a disease-causing pathogen. Vaccination uses either inactivated or attenuated pathogens or preparations of the pathogen`s antigens. A widely studied model are protein-based subunit vaccines, which possess several advantages such as safety profile, defined structure, and ease of production. However, a limitation is an insufficient immunogenicity due to their instability over prolonged periods, their monovalent structure, and lack of immunostimulatory components. Therefore, immunostimulatory molecules, i.e., adjuvants, are typically added during vaccine administration to augment antigen immunogenicity and thus enhance vaccine efficacy.

   A relatively new approach to further improve the immunogenicity of subunit vaccines is the use of nanoparticle platforms that present monovalent antigens in a polyvalent, repetitive manner. Due to similar size and surface properties, the nanoparticles mimic the pathogen structure and are therefore expected to evoke an immune response comparable to natural infections. For this purpose, we apply silica nanoparticles (SiNPs) to immobilize the envelope trimer of HIV-1 (Env) or the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 in a defined and oriented manner on their surface.

As the decorated nanoparticles mimic some viral properties, they help to guide the antigen to the destination where adaptive immune response takes place. Thus, the nanoparticle platform improves the uptake of the antigen into the lymphatic system and the trafficking of the antigen to the lymph nodes. Once arrived in the lymph nodes, the nanoparticles also provide for a prolonged presentation of the antigen and a more efficient B cell activation by increased avidity. The corresponding soluble, monovalent antigen has been shown to be by far less efficient.

The lecture is organised on behalf of the graduate programme in pharmaceutical sciences, Drug Research Academy, by Associate Professor Andrea Heinz, LEO Foundation Center for Cutaneous Drug Delivery, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen.

The DRA lecture is free of charge and open for attendance by all interested parties. It is not necessary to pre-register.