Effect Of β-Glucan On The Immune Response Of NDV Inactivated Vaccine

The typical incidence of Newcastle disease（ND）characterized by fulminant disease is rare in Chinese chicken industry,while the non-typical ND is increasing.The main method of preventing ND is the immunization of vaccines.In particular,the immune effect of inactivated vaccines is relatively stable.The immune effect of inactivated ND vaccine is determined by the injected dose and antigen content.The immune adjuvant plays a key role in obtaining good prevention and control of disease.Beta glucan is widely distributed in fungi,bacteria and plants,and it is a component of a variety of biological cell walls.It has a variety of biological activities,including improving animal immune response,anti-tumor and anti-radiation.However,it has not been reported that theβ-glucan most immune adjuvant affects the immune effect of inactivated Newcastle disease vaccine.In this study,β-1,3/1,6-glucan was used as an adjuvant to evaluate the effect of SP-chicken on immune function and production.The effect of inactivated vaccine against Newcastle disease was tested.The results showed that:（1）β-1,3/1,6-glucan significantly increased weight gain,immune organ index,and CD₄⁺Tcell proliferation in SPF chickens 14 days later.β-1,3/1,6 glucan has an immunopotentiating effect and can be used as an immune adjuvant to enhance vaccine immunity.（2）SPF chickens were immunized with 0.5%or 2%β-1,3/1,6 dextran and ND inactivated vaccines.The titers of NDV specific antibodies in SPF chicken sera were compared on different days after immunization,indicating thatβ-1,3/1,6 dextran can increase humoral immunity.By flow cytometry,the proliferation of CD₄⁺T and CD₈⁺T cells was detected and analyzed after 14 days of immunization,indicating that 2%ofβ-1,3/1,6 glucan can increase the levels of cellular immunity.（3）Detection of chIL2,chIL6 and chILFN-r in spleens of SPF chickens after immunization with 0.5%or 2%β-1,3/1,6 glucan mixed with ND inactivated vaccine after immunization with Real-time PCR Transcriptional levels indicate that the 2%mixed group can significantly increase the level of cytokine transcription.The protection rate in the 2%mixed group was 100%.There were two cases in the 0.5%mixed group and the ND inactivated vaccine control group,it showed that the mixture of 2%β-1,3/1,6 glucan and ND inactivated vaccine can significantly increase the vaccine protection rates.In summary,β-1,3/1,6 dextran could significantly increase NDV-specific antibody titer and T-cell immunity,improve the protective effect of inactivated NDV vaccine,and be expected to become a candidate novel veterinary vaccine.