Molecular And Cellular Pathology Of Porcine Contagious Pleuropneumonia And Protective Efficacy Of Recombinant Outer Membrane Protein P2 Against Challenge Of Actinobacillus Pleuropneumoniae

Porcine contagious pleuropneumonia is a severe harmful acute respiratory infectious disease caused by Actinobacillus pleuropneumoniae infection. Studying molecular and cellular pathogenic mechanism and screening vaccine is very important.In order to investigate the molecular and cellular mechanisms of pulmonary pathogenesis in mice infected by Actinobacillus pleuropneumoniae(APP), Mice were intranasally infected by Actinobacillus pleuropneumoniae. Pulmonary gross lesion and histological pathology by H-E staining_were observed.Expression levels of Caspase-1, Caspase-3, TNF-a, IL-1?, IL-6, IL-18, TLR4 in lung of mice were detected by RT-PCR and qPCR. The mice were killed at 48 hours postinfection. Serious pulmonary hemorrhage and inflammation in infected mice were observed. Expression levels of caspase-1, caspase-3, TNF-a, IL-1?, IL-6, IL-18, TLR4 detected by RT-PCR and qPCR increased and expression levels of caspase-3 were not changed in lungs of infected mice by APP.TLR-4 involed pulmonary lesion of infected mice by increasing expression level of pro-inflammatory cytokines of TNF-a, IL-1?, IL-6, IL-18. TLR-4 signaling involved Pyroptosis related with caspase-1 in pulmonary inflammation of infected mice by APP.In order to detect immune protective efficacy of App outer membrane protein P2 against challenge infection by App, App outer membrane protein P2 were screened as a vaccine candidate by bioinformatics. APP recombinant outer membrane protein P2 (ompP2) were produced by gene recombinant technology. Serum IgG titer of mice were detected by ELISA pre-/post incoubnation with r ompP2 plus aluminum adjuvant. Immune protective efficicay against App infection were detected 2 weeks post third incubation.RompP2 protein plus aluminum adjuvant vs sc. could induced high IgG level and high immune protective efficacy against challenge infection of App in mice.RompP2, the recombinant protein had good immunogenicity and induced high immune protective efficacy against challenge infection of App in mice.