Vaccines based on recombinant protein antigens often require immunostimulants. Both nanoparticles and chitosan and its derivatives can enhance immunogenicity. For this reason, in the presented studies, PLGA nanoparticles were functionalized with different chitosan derivatives and optimized as effect enhancers for the pneumococcal protein antigen PspA4Pro.

The corona virus disease COVID-19 has changed the world. To combat the pandemic, researchers and companies around the world are working to develop vaccines and medicines. Chitosan also has potential in the area of vaccine development and functionalization of protective equipment such as respirators. We have prepared summaries of recent publications on chitosan as an aid in the fight against corona.

The global spread of SARS-CoV-2 can only be contained through vaccine development. Vector vaccines (DNA and viral) can be produced rapidly and inexpensively with current synthesis technologies. Challenges with DNA vaccines include degradation by DNases, inefficient uptake by antigen-presenting cells, and low immunogenicity. The Quil-A-loaded chitosan particulate adjuvant system (QAC) enables transport of plasmid DNA directly to target cells and delayed release over time. Here, we present two recent studies about chitosan-based delivery systems for vaccines.

Adjuvants in vaccines are potent enhancers, which ensure that even small amounts of pathogens induce a permanent immune response. They are particularly necessary for inactivated vaccines and vaccines with antigen subunits. Several studies investigated chitosan as an adjuvant or antigen delivery system in various formulations (gels, aqueous dispersion, micro- and nanoparticles).