DNA Vaccine Of Avian Reovirus σC Gene Delivered By Attenuated Salmonella Typhimurium And Its Immunogenicity

AVA also called "infectious tenosynovitis",was found a chronic Infectious disease caused by Avian Reovirus in recent years.It features itself by causing damages to tarsus, metatarsophalangeal joint tendon and cardiac muscle.The disease which is widely occurred around the world causes great economic losses to the poultry industry.The proteinσC which carries the specific reaction surface antigen of ARV,is the minimum protein of outer capsid in Avian reovirus and can stimulate organism to produce the protective neutralizing antibody.During the study,we constructed DNA vaccine of Avian reovirusσC Gene delivered by Attenuated Salmonella Typhimurium and studied its immunogenicity.1.The construction of DNA vaccine of Avian reovirusσC gene delivered by attenuated Salmonella Typhimurium and identificationA pair of primers were designed and synthesized according to the previously publiched sequence of proteinσC gene of Avian reovirus(ARV)and used to amplifyσC gene by polymerase chain reaction.TheσC gene was cloned to the pMD19-T vector to construct the cloned vector pMD19T-σC.The result of nucleotide sequencing show the cloned gene fragment is 981bp。And the nucleotide sequence homology of the amplified target fragments and the frequent reported S1133σC inGenBank is between 98.9%and 99.8%, and the homologous amino acids homology is between 97.2%and 99.4%。Then recombinant eukaryotic expression vector pVAX1-σC was constructed through insertingσC gene into expression vector of pVAX 1.The recombinant plasmid pVAX1-σC was transfected into COS-7 cells.The expressedσC protein was successfully detected with indirect immunofluorescent assay.Furthermore,the recombinant pVAX1-σC were successfully transformed into the Attenuated Salmonella Typhimurium strain SL7207,and the transform recombinant was named SL7207(pVAX1-σC).Six-day-old chickens were orally innoculated with recombinant attenuated Salmonella typhimurium SL7207(pVAX1-σC)at dosage of 10~9 CFU,and the results showed that the recombinant bacteria were safe to chickens.2.The elementary research of immunogenicity of DNA vaccine of Avian reovirusσC gene delivered by attenuated Salmonella TyphimuriumSix-day-old chickens were twice immunized orally withSL7207(pVAX1-σC)at dosage of 2×10~9 CFU,and this recombinant bacteria could significantly elicit specific serum of IgG antibody immune response for ARVσC gene in immunized chickens,compared with SL7207(pVAX1) and PBS immunized chickens.The results of virus attack test showed the efficiency of protection of DNA vaccine of Avian reovirusσC gene delivered by attenuated Salmonella Typhimurium is 66.7%.