Research into vaccines has recently been focussed on enhancing the immune response by encapsulating antigens in nano- and micro-particles. There are 3 main advantages of antigen encapsulation:
1. The particles prevent antigen degradation
2. The particles facilitate the ingestion of chemical agents into antigen-presenting cells
3. The particles can be engineered to carry adjuvants
In line with these advantages, biomedical engineering researchers at the University of Arkansas have announced the results of research that is likely to ignite further interest in antigen encapsulation technology. The research, published in Biomaterials, demonstrated that by encapsulating protein antigens in chitosan, three important immune responses could be improved.
“A great deal of effort has been spent developing delivery systems capable of enhancing vaccine responses with specific antigens,” said Bhanu Koppolu, a doctoral student and senior research assistant, in a press release. “We believe we have developed a system that will accomplish this. In all tests, our material outperformed soluble antigen. The encapsulation of antigens in chitosan particles enhanced uptake, activation and presentation by antigen-presenting cells.”
Chitosan is a natural polysaccharide derived primarily from crustacean exoskeletons. Chitosan, according to the researchers, is an ideal vehicle for delivering vaccine agents because the particles are easy to produce, are muco-adhesive, and are able to loosen gaps between layers of tissue. Chitosan's ability to form nano- and microparticles in mild aqueous conditions thus preserves the antigenicity of loaded polypeptides.
Focussing solely on antigen-presenting cells (APCs), researchers used flow cytometry analysis to demonstrate that antigens encapsulated in chitosan not only enhanced the activation of APCs, but also increased the release of pro-inflammatory cytokines and stimulated a higher proliferative response in antigen-specific T lymphocytes compared to soluble antigen. The researchers thus conclude that the data suggests that encapsulation of antigens in chitosan particles enhances uptake, activation and presentation by APCs.
Do you think particle-based vaccine delivery systems will be the future of vaccine technology?
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If you'd like to know more about strategy and innovation in vaccines, you might like to consider attending the World Vaccine Congress and Expo 2013 on the 16-18 April 2013, Gaylord National Hotel and Convention Center, Washington DC. You can download the brochure here.
Reference: Bhanuprasanth Koppolu, David A. Zaharoff. The effect of antigen encapsulation in chitosan particles on uptake, activation and presentation by antigen presenting cells. Biomaterials, 2013; 34 (9): 2359 DOI: 10.1016/j.biomaterials.2012.11.066