HA蛋白S227N突变对基于新城疫病毒载体的H7N9亚型禽流感疫苗免疫原性的影响OA北大核心CSTPCD

The purpose of this study is to evaluate the effect of the S227N substitution in the hemagglutinin(HA)on the immunogenicity of Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccine in chickens.The recombinant NDV expressing the HA with the S227N substitution was generated using reverse genetics and its biological characteristics and immunogenicity in chickens were as-sessed.The results indicated that the recombinant NDV expressing the HAS227N had low virulence(MDT＞120 h),high virus titer(HA titer∶512;EID50∶109.3/mL)and replication capacity in chicken embryonated eggs.These features were comparable to those of the vector virus and the recombinant NDV expressing the wild-type HA protein.The S227N substitution did not change HA expression pattern in the cells inocu-lated with the recombinant NDVs.Additionally,the recombinant NDVs expressing the HAS227N or the wild-type HA protein induced high hemagglutination-inhibition(HI)antibody titers against NDV.The HA S227N substitution increased seroconversion of chickens immunized with the recombinant NDV,whereas it failed to significantly elevate HI titers against H7N9 virus.In conclusion,the S227N substitution in HA cannot significantly enhance the immunogenicity of NDV-vectored H7N9 vaccine in chickens.This study presented helpful information for the design,optimization and evaluation of H7N9 avian influen-za vaccines.