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Couple of ways to improve vaccines…
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Vaccines are providing resistance against certain infectious agents by stimulating adaptive immune response. Idea that immunity could be boosted using attenuated or dead viruses is very old. First notes about primitive vaccination are dating back in 18th century. Today, vaccination is common practice and number of available vaccines (for different purposes) on the market is growing rapidly. A lot of things changed and improved since first vaccine was invented.

Cancer vaccines are one of the relatively new inventions in the vaccination field. They are used either to prevent cancer development or as a part of cancer therapy. Typical examples are vaccines that protect against cervical (induced by human papiloma virus) and liver carcinoma (induced by hepatitis B virus). Antigens used to provoke immune system are usually proteins isolated from the cancer cells. Other type of anti-cancer vaccines could enhance immune response in situ. Modified herpes simplex virus in the OncoVEX GM-CSF vaccine is genetically engineered to carry GM-CSF gene. This gene is stimulator of the immune response. During viral replication (which is selective - tumor based), GM-CSF level will increase and boost immune system response. Main problem with vaccines that could be used in cancer treatment is associated with the antigen of choice. Tumor cells are bearing unique and shared antigens. Shared antigens are mutual for many cancer types and unique are tumor specific. Mutation that is characteristic for some viruses is making antigen selection process even harder. Success in cancer therapy is depending on couple of factors. Illness stage: the sooner treatment starts, the better outcome will be. Right antigen choice: perfect vaccine could induce immunization against couple of antigens, minimizing the chance on developing treatment resistance. Health status of the individual that is undergoing the treatment: healthier immune system will result in longer lifespan.

Adjuvants are tightly associated with vaccines. Those agents don’t induce immune response on their own but significantly increase immunization by enhancing body reaction to the ingested antigen. Adjuvants (like aluminium salts, some type of oils, virosomes…) are mimicking pathogen-associated molecular patterns and trigger whole set of immune cells that are typically seen during infection (dendritic cells, macrophages, lymphocytes…). Adjuvant needs to match antigen. Some combination induce weaker than expected immune response, can provoke local reaction or trigger IgE response. Recent study focused on finding new adjuvants that could be safely applied and provide efficient immune response. Nanotechnology offered solution. Nanoparticles as adjuvants for vaccine are currently under investigation. Couple of studies showed that nanoparticles carrying proteins, peptides or DNA could deliver it safely to the targeted cell (dendritic cells, for example); often more than one (encapsulated) antigen will be delivered; slower (controlled) release of the antigen could be achieved; being biodegradability and non toxic, nano-particles could be easily degraded and eliminated after antigen is released. Gamma-PGA nanoparticles will be tested soon for its potential use as next adjuvant in vaccine development.

Vaccines are usually delivered subcutaneously, using needle. Couple new options for vaccine delivery arose recently. Nanopatches could be used for transdermal delivery of the vaccine. They consist of 20,000 microscopic projections per square inch and unlike needles - they don’t penetrate to the muscle. Beside lack of pain, other advantage of nanopatch vaccine delivery is higher concentration of immune cells in the skin compared to a muscle. Application is very simple; once nanopatch is glued to the skin, it will release its content to the skin and induce immune response. New method that could improve vaccine delivery even more is associated with bacterial spores that could serve as carriers. Bacillus suptilis derived spores could last for million years, they are highly resistant to different environmental condition and germination will happen only under special circumstances. Spores carrying vaccines against tuberculosis, influenza and tetanus are already tested with promising results. Spores are stable and substantial amount of money could be saved by eliminating expensive preservation methods. Bacillus subtilis is easily grown in the laboratory (spore are inexpensively produced). Nasal or oral vaccine administration routes are much more convenient than classical needle approach. Also, they could be developed as biofilms for the sublingual delivery. Finally, adverse effects associated with different excipients could be avoided using spores as delivery system.

Vaccines are one of the most influential treatments ever designed with tremendous effect on the global health. They are associated with a lot of failures as well, but modern age and development of technology improved vaccine industry a lot.
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Couple of ways to improve vaccines…00