| Newcastle disease (ND) is an acute, contagious severely infection disease caused by Newcastle disease virus (NDV), one of which does great harms to the animal husbandry. It has been defined as type I infection disease by International Veterinary Situation.Currently, it is usually to inoculate vaccines to prevent NDV, such as La Sota live vaccine and inactivated NDV vaccine, but these two vaccines both have more or less shortcoming in practice. Live vaccine may be recovered powerful virulence because of variation; while, inactivated NDV vaccine is slow in protection antibody responses. At the same time, immunoprotection period is short. Therefore, a new and improved method of immune effectiveness is urgently needed in NDV vaccine study work. Transforming dosage form is one possible method to facilitate this work. Nowdays, nanopartciles mucosa immunity delivery system seems to be one of the most hopeful ways to solve above problem.In this study, the research interest is focused on establishing a model with La So-ta live vaccine immobilized into chitosan, which was prepared using a ionic gelation method. The formulation, preparation procedure, influence factors, physicochemical characteris-tics and stability of NDV-Chs-NPs were evaluated. Western blotting tests were carried out to investigate the antigenicity of NDV after the NDV-Chs-NPs have been done. The cytotoxicity tests and safety tests were used to determine the safety of NDV-Chs-NPs mucosa immunity delivery system. The protection antibody responses of NDV-Chs-NPs were evaluated. The results of study demonstrate that the NDV-Chs-NPs have been produced with suitable size, morphous regulation, extremely spherical shape, regular and well-distributed. The NDV-Chs-NPs produced by the optimal formulation were mean size (371.1nm) and proper Zata Potential (+2.84mV). The entrapment efficiency was (74±3.7)%. Furthermore, the results of western blotting tests indicate that biological performance of NDV was maintained. Also, releasing tests in vitro has shown that NDV-Chs-NPs could make NDV sustained release. Meanwhile, the potency tests in vivo demonstrated that NDV-Chs-NPs could yield better protection antibody responses than La Sota live vaccine. The mucosa immunity delivery system of NDV-Chs-NPs had an excellent safety of being satisfactory, which could be proved by cytotoxicity test and safety test.NDV-Chs-NPs has implemented mechanism of the long-term release of the antigen, which could decrease the expense of the vaccine production, dose of the vaccine, times of inoculation and increase the methods of inoculation. Also, it can provide a more reliable mucosa immunity delivery system for clinical application of NDV vaccine to meet a safety request. |
