Study On Preparation And Immune Efficacy Of Newcastle Disease Chitosan Microsphere Vaccine

New Castle disease is an acute and highly contagious disease caused by Newcastle disease virus, one of which does great harms to the poultry industry. The important key to prevent NDV is to apply vaccine, such as La Sota live vaccine and inactivated NDV vaccine, but these two vaccines both have more or less shortcoming. It can produce higher mucosal immunity titers by taking vaccine orally, meanwhile it can induce hμmoral and cell-mediated immune response and mucosal immunity strongly. Therefore, it becomes the focus of the research, that preparing new pattern vaccines taking orally.Newcastle Disease (ND) chitosan microsphere vaccine was prepared using chitosan as capsule wall material, Newcastle Disease virus (NDV) as core material, glutaraldehyde as cross-linking material, we get well-distributed chitosan microsphere with smaller particle size. The results show that the best preparation condition of the chitosan microsphere is: using Liquid Paraffin as organism dispersed medium, preparing chitosan(2.5%)-acetic acid (2%) solut- ion, making the volume ratio of Liquid Paraffin and chitosan-acetic acid solution as 2.5:1,at the condition of Tween-80 8mL, Glutaral dosage 2mL, keeping high speed stirring (rotation speed≥4000 r/min), cross link 1.5h, we get the chitosan microsphere, even particle diameter of 5.83μm, Surface smooth and glossy, no obviously pore space, yellow brown pykno-ball.In order to find MTT method for detecting Lymphocyte transformation, we have done a lot of experiments to choose ConA concentration, cell concentration, cultivation hours. Finally we determine the best cultivation condition of the method: 5×106 /mL cell concentration, 20μg/mL ConA concentration, at 40℃, cultivating 56h. The result shows that the method could be used to detect the chicken's Lymphocyte immunity function.Other more, Newcastle Disease (ND) chitosan microsphere vaccine's safety and potency were evaluated. The SPF chickens were immunized with ND chitosan microsphere vaccine, La Sota live vaccine and inactivated NDV vaccine respectively. To evaluate vaccine's immune efficacy, MTT was used to measure lymphocytes proliferation in vitro, HI to measure serum special IgG and ELISA tests to detect mucosal sIgA titers. The results show that ND chitosan microsphere vaccine was safe, could induce humoral and cell-mediated immune response and mucosal immunity strongly. The results of the potency tests conformed that the vaccine could produce good protective effect.