Immune Response Of Mice Against Swine Influenza With A Recombinant Pseudorabies Virus Expressing The HA Of H3N2 Subtype Swine Influenza Virus

Swine influenza virus(SIV)belong to type A influenza virus, and SIV H3N2 subtype is prevalent inChina, which can cause an infectious respiratory disease in swine. Swine is the only animal which can beinfected by either avian or human original influenza viruses, and can be considered as the intermediate hostfor the process of genetic reassortments between viruses of different hosts. Leading to the generation ofnew strains of influenza virus. Recently, no vaccine against H3N2 SIV is commercially available in China.Vaccination against H3N2 SIV can reduce economic lose and play a role in food safety and public health.A pseudorabies virus (PRV) transfer vector(pLTK-HA)containing HA gene of H3N2 SIV used tocotransfect with genomic DNA of PRV Bartha-K61 into Vero cells. After many cycles of blue plaguepurification and PCR identification,we got a PRV recombinant containing hemagglutinin (HA) gene ofH3N2 SIV and designated as rPRV -HA. Expression of SIV HA by rPRV-HA is about 60ku asdemonstrated by Western blotting analysis. Indirect immunofluorescence assay (IFA) demonstrated that HAwas expressed by rPRV-HA in cytoplasm.The BALB /c mice were used as a immunologic model toevaluated the recombinant. A total of 150 8-week-old female BALB/c mice were used in this study. Themice were inoculated intranasally with 105.0 TCID50/0.2ml,50ul of rPRV-HA (rPRV-HA group, n=60) orattenuated vaccine Bartha-K61 (Bartha-K61 group, n=60), and another two unimmunized groups served aschallenged group (n=20) or unchallenged group (n=10). Each animl was challenged with 105.0 EID50/0.2ml,50ul of the SIV SwHLJ74 28 day postimmunization. Recombinant virus was found to mainly propagate inthe lung of immunized mice. The antibodies against PRV were detected by IFA after 14 days postinfectionin both rPRV-HA and Bartha-K61 groups. SIV-specific antibodies were detected by hemagglutinationinhibition test and IFA in rPRV-HA group ,but not detected in the control groups. The rPRV-HA immunizedmice were protected from same subtype virus challenge, as indicated by reduced virus replication, milderpathological changes, and boosted antibody responses to SIV post-challenge.Therefore the results indicatethat the rPRV-HA could pretect mice from challenge of SIV SwHLJ74 and could be used as a potentialvaccine.