Development of new vaccination technology has been hindered by a lack of new adjuvants to enable development of protective immunity using different vaccine delivery methods. A vaccine delivery system using oral adjuvants would be applicable across species for both individual and mass vaccination in both the medical and veterinary fields. We sought to create an oral nanoparticle (NP) vaccine delivery system that is easy to produce and uses polymers as oral adjuvants with killed virus. Our hypothesis was gelatin and chitosan would enhance viral uptake and stimulate immune cells to produce protective immunity. This would allow the safer killed form of each virus to be used in place of modified live (MLV) viruses and avoid undesirable side effects like immunosuppression. The research objectives were to
1. Fabricate and characterize gelatin NPs encapsulating inert materials of similar size and shape to the viruses of interest for fabrication proof-of-concept
2. Modify the NP delivery system to minimize immune cell cytoxicity for the vaccine delivery application
3. Fabricate and characterize FPV and HEV viral nanoparticles' stability, cellular uptake/infectivity, and released viruses' ability to replicate
4. Compare the abilities of the killed HEV nanovaccine, killed HEV with loose gelatin and chitosan polymers (no nanoparticle), and a live HEV commercial vaccine to induce textit{in vivo} seroconversion, protective immunity, and side effects during clinical and challenge studies in turkeys
We proved our hypothesis to be correct in addition to demonstrating matching the encapsulation material size to empty NP size leads to preferred encapsulated NP formulation parameters, chitosan stabilizes the NP formulation bypassing the need for cytotoxic crosslinkers, and paraformaldehyde is able to kill virus prior to vaccine formulation while still preserving virus morphology sufficiently for immune cell recognition. This development constitutes one of the first novel adjuvants discoveries in 70 years and opens the door for conversion of injectable vaccines to oral delivery across species. / Doctor of Philosophy / Most vaccinations use needles to inject a live but weakened virus into the body, which causes a mild infection. The body learns to protect itself using this weak form of the virus, so that when the body encounters a stronger form of the same virus later on in life, the body is able to quickly kill the virus and recover from the infection. If we could package a dead virus with the right mixture, we could get the body to recognize the dead virus and learn to protect itself just as the body does with the weaker, live virus. This would avoid the mild infection and the unpleasant symptoms associated with the live virus injection and allow us to use a safer dead virus vaccine. Additionally, with the right package, we could drink our vaccines instead of using injections. Here, we tried to create a drinkable, safer dead virus packaged with gelatin and shellfish fiber in a vaccine that allows the body could recognize the dead virus and learn to protect itself similarly to the live virus vaccine. The goals of this work were to:
1. Practice putting plastic beads of similar size and shape to viruses in gelatin packages to understand how to safely package viruses in gelatin as part of making the new drinkable vaccine
2. Adjust the process of making the gelatin plastic bead packages to work well with cells in the laboratory as a second step toward making safe vaccines
3. Use the packaging process to package a dead chicken virus and a dead turkey virus separately with gelatin and shellfish fiber and measure each packaged virus
4. Test the dead packaged turkey virus vaccine with gelatin and shellfish fiber, the dead unpackaged turkey virus with loose gelatin and shellfish fiber, and a live turkey virus that is currently used as a vaccine in turkeys to see which allows the body to protect itself without causing side effects
We showed that using plastic beads of similar size to empty gelatin and shellfish fiber packages creates the preferred packaged plastic bead measurements. The shellfish fiber kept the packages intact and from falling apart, so no additional chemicals were needed. The preservative used to kill the virus worked while still keeping the virus recognizable to the body. This new packaging for vaccines is a breakthrough in vaccine development and will allow us to change injectable vaccines to drinkable vaccines in other animals and humans.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/102504 |
| Date | 06 September 2019 |
| Creators | Cary, Jewel Maria |
| Contributors | Department of Biomedical Engineering and Mechanics, Whittington, Abby Rebecca, Pierson, Frank W., Lee, Yong Woo, Van Dyke, Mark, Edgar, Kevin J. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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