Inhibitory Effect Of Pine Pollen Polysaccharides On H9N2 Subtype AIV And Immune Enhancement To Newcastle Disease-avian Influenza Inactivated Vaccine

The spread of Avian influenza virus(AIV)spreads all over the world and can infect a variety of birds such as chickens,ducks,turkeys,etc..Newcastle disease virus(NDV)infection can cause an acute highly contagious disease.Chickens are most easily infected by Newcastle disease virus.The combination of Avian influenza virus and Newcastle disease virus has resulted in a higher incidence of infection in chickens and there is no special treatment drug.At present,vaccination is mainly used to prevent the occurrence of Avian influenza and Newcastle disease.However,the lack of immunity,quality of vaccine,and short duration of immune protection often results in the failure of immunization.At the same time,due to the regional environment,climatic conditions and other reasons,caused by the virus mutation,increased virulence,so that the epidemic prevention of the disease is facing great challenges.The current important task is the study of the vaccine’s immune effect and its safety.Therefore,finding a safe and effective immune enhancer to improve the immune effect of the vaccine is the current research hotspot and focus.Plant polysaccharide is a good biological response modifier,which has the advantages of improving immunity,side effects,safety and non-toxicity.It is expected to be researched and developed into a new vaccine adjuvant or immune enhancer.The laboratory experiments showed that TPPPS has the function of improving immunity and enhancing vaccine immunity.At the same time,TPPPS has the advantages of natural,green,and no side effects.Based on the antiviral and immunomodulatory properties of TPPPS,three different doses of TPPPS were designed to co-immunize 14-day-old chicks with Newcastle disease-avian influenza combined vaccines to study the effects of pine pollen polysaccharides on the vaccine.influences.Explore the mechanism of its enhanced vaccine immunity and lay a solid foundation for the development of new biological response modifiers.This study is divided into the following two parts:Part I Inhibitory effect of pine pollen polysaccharide on H9N2 subtype influenza virusAccording to literature data,the best antiviral period of TPPPS is the adsorption period,and its preventive effect is more significant.In this experiment,the H9N2 subtype avian influenza virus was used as an example to verify the role of TPPPS in inhibiting the virus through invitro cell infection and immunofluorescence tests.The results showed that TPPPS could significantly inhibit the growth of H9N2 subtype avian influenza virus in vitro,and had the best inhibitory effect on the virus during the adsorption period.In order to compare the preventive and therapeutic effects of TPPPS,the serum antibody levels of animals used before and after challenge with TPPPS were tested by in vivo challenge protection tests.The results showed that the level of AI-HI antibody in the group before TPPPS challenge was better than that in the group after challenge This test proved that the pine pollen polysaccharide has the best effect during the prevention period.This part of the test results shows that early use of TPPPS as an immunopotentiator is more conducive to the improvement of the body’s immune function.Part II The Immunoenhancement Effect of Pine Pollen Polysaccharides on Newcastle Disease and Bird Flu Inactivated VaccineTo investigate the immune enhancement effect of Taishan pine pollen polysaccharide(TPPPS)on chicks inoculated with Newcastle disease-avian influenza combined inactivated vaccine.In this experiment,360 1-day-old healthy chicks were randomly divided into 6groups,60 in each group.They were given orally with different doses of TPPPS and physiological saline on a day old,and they were orally administered continuously for 10 days and immuned of Newcastle Disease-Avian Influenza Vaccine at 14 Days of Age.In order to investigate the immunopotentiating effect of TPPPS on inactivated vaccine,the related immune indexes of each group were determined.The results showed that the levels of ND,HI antibody,IL-2,IL-4,IFN-γ,CD4 + / CD8 + ratio and peripheral blood lymphocyte transformation rate of TPPPS were significantly higher than those of control group(P<0.05),and TPPPS of high dose group(40 mg/mL)was superior to low dose group(10 mg/mL).The results showed that the appropriate dose of TPPPS on the Newcastle disease-avian influenza inactivated vaccine immune effect of a significant enhancement.These findings indicated that TPPPS had a significant effect on the immune effect of Newcastle disease-avian influenza inactivated vaccine and the group of 40 mg / mL had the best immune effect.