Mass Production of Virus-Like Particles Using Chloroplast Genetic Engineering for Highly Immunogenic Oral Vaccine Against Fish Disease

Nervous necrosis virus (NNV) is the causative agent of viral nervous necrosis (VNN), which is one of the most serious fish diseases leading to mass mortality in a wide range of fish species worldwide. Although a few injectable inactivated vaccines are commercially available, there is a need for more labor-saving, cost-effective, and fish-friendly immunization methods. The use of transgenic plants expressing pathogen-derived recombinant antigens as edible vaccines is an ideal way to meet these requirements. In this study, chloroplast genetic engineering was successfully utilized to overexpress the red-spotted grouper NNV capsid protein (RGNNV-CP). The RGNNV-CP accumulated at high levels in all young, mature, and old senescent leaves of transplastomic tobacco plants (averaging approximately 3 mg/g leaf fresh weight). The RGNNV-CP efficiently self-assembled into virus-like particles (RGNNV-VLPs) in the chloroplast stroma of the transgenic lines, which could be readily observed by in situ transmission electron microscopy. Furthermore, intraperitoneal injection and oral administration of the crudely purified protein extract containing chloroplast-derived RGNNV-VLPs provided the sevenband grouper fish with sufficient protection against RGNNV challenge, and its immunogenicity was comparable to that of a commercial injectable vaccine. These findings indicate that chloroplast-derived VLP vaccines may play a promising role in the prevention of various diseases, not only in fish but also in other animals, including humans.

Knowledge Creation on Edible Vaccines

In this paper we delve into the health sector and explore the way vaccines might change in the near future. As new challenges emerge, health professionals are faced with the need for innovative, effective answers to many issues, such as health-threatening viruses and diseases, that grow increasingly more complex, calling for new and practical solutions. Building on this framework, we have decided to address edible vaccines - a completely innovative and simpler way to administer vaccines - not only to understand if it is viewed in a favorable light but also to find out how the knowledge regarding these vaccines can be increased. After a thorough literature review, it became clear that the information about edible vaccines is not evident and easy to access. We then decided to apply a mixed methodology in our study, based on 15 interviews, in person and by email, addressing healthcare professionals, with the intent of gathering their experience and possible knowledge about vaccines. Additionally, an online survey was created and answered by 370 concerned citizens, in order to ascertain their knowledge and receptiveness to this matter. Hereupon, we concluded that, in both samples, there was very limited knowledge about these vaccines, it becoming obvious how important it is to transmit qualified information through accessible means, such as newscasts, scientific papers and magazines, health centers and hospitals, among others. Regarding the level of acceptance by the public in general, our results show that this innovation is dependent on its correct disclosure and propagation, since it is of great advantage and benefit for society. In sum, how the relevant knowledge (including proof of effectiveness) is managed and disseminated will be key. traditional vaccines, edible vaccines, field work, mixed methodology, Genetically modified organisms, GMOs

Immunization

Immunization is one of the most successful medical interventions ever developed: it prevents infectious diseases worldwide. The basis for its success is that the human immune system can respond to vaccines by producing pathogen-specific antibody and memory cells (both B and T cells) which protect the body should the pathogen be encountered. Most currently licensed vaccines contain live or killed bacterial or viral constituents, bacterial polysaccharides, or bacterial toxoids, while new types of vaccines are being developed that contain DNA. Most vaccines are delivered directly into skin or muscle via needles, or they are administered orally. New edible vaccines and vaccines delivered via the skin without the use of needles are being developed. The Expanded Programme on Immunization, set up by the World Health Organization to define which vaccines should be delivered in resource-poor countries, has done much to increase vaccination coverage among infants most at risk of infectious diseases.