A number of ingredients have been used as carriers to successfully deliver vaccines and to enhance their immune response. These include peptides, liposomes, lipid nanoparticles and polymers to name a few. Recently, Lam et al describe the use of artificial cell membrane (ACM) polymersome technology as delivery vehicle for COVID-19 spike protein vaccine that leads to efficient entry into the antigen presenting cells, thereby eliciting a stronger and lasting immune response.
Humans have been dealing with infection since times immemorial. A number of preventions and treatments and are available to deal with infections, of which vaccination has been one of important ones as it provides long lasting immunity against the disease. However, vaccine delivery and elicitation of a robust immune response has remained a challenge since the first vaccine was done in 1796 by Edward Jenner. A number of methods have been developed such as use of peptides, liposomes, lipid nanoparticles, polymers etc. to overcome these challenges and hunt is for novel methods for safe and effective delivery of vaccines that leads to a robust immune response.
Polymersomes is one such technology that consists of self-assembling nano-particles made of rationally designed polymers that have been successfully used in drug delivery of cancer immuno- therapeutics (1). The study involved delivery of cGAMP (an agonist of stimulator of interferon genes (STING)) as polymersomes that led to an increase in the efficacy of cGAMP resulting in an effective immune response that inhibited tumour growth and build enough memory to counter a tumour rechallenge. Use of polymerosmes have been reviewed and described as “the sixth revolution in vaccinology” by David Dowling’s group (2). The review describes the use of self-assembled PEG-b-PPS polymersomes with OVA as an antigen and CpG as an adjuvant (CpG) to induce and enhance CD4+ T cell response in the spleen and lymph nodes (3). Flash nanoprecipitation has been used as a scalable technique for the self-assembly of polymers resulting in polymersomes that can then be used as a delivery vehicle (4) .
Lam et al have exploited the use of self-assembled polymersomes to efficiently deliver the SARS-CoV-2 spike protein in antigen presenting cells of mice. These ACM polymersomes consisted of amphiphilic block copolymer that elicited strong neutralising antibody titers that lasted for 40 days (5).
Polymersome technology thus represents a promising tool for efficient delivery of vaccines in future.
- Shae, D., Becker, K.W., Christov, P. et al. Endosomolytic polymersomes increase the activity of cyclic dinucleotide STING agonists to enhance cancer immunotherapy. Nat. Nanotechnol. 14, 269–278 (2019). https://doi.org/10.1038/s41565-018-0342-5
- Soni, D., Bobbala, S., Li, S. et al. The sixth revolution in pediatric vaccinology: immunoengineering and delivery systems. Pediatr Res (2020). https://doi.org/10.1038/s41390-020-01112-y
- Stano A, Scott EA, Dane KY, Swartz MA, Hubbell JA. Tunable T cell immunity towards a protein antigen using polymersomes vs. solid-core nanoparticles. Biomaterials. 2013 Jun;34(17):4339-46. doi: https://doi.org/10.1016/j.biomaterials .2013.02.024. Epub 2013 Mar 9. PMID: 23478034.
- Sean Allen, Omar Osorio, Yu-Gang Liu, Evan Scott, Facile assembly and loading of theranostic polymersomes via multi-impingement flash nanoprecipitation, Journal of Controlled Release, Volume 262, 2017, Pages 91-103, DOI; https://doi.org/10.1016/j.jconrel.2017.07.026
- Lam JH., Khan AK., et al 2021. Next generation vaccine platform: polymersomes as stable nanocarriers for a highly immunogenic and durable SARS-CoV-2 spike protein subunit vaccine. Preprint. bioRxiv 2021.01.24.427729; Posted January 25, 2021. DOI: https://doi.org/10.1101/2021.01.24.427729