Evaluation Of Immunological Effectives Of Actinobacillus Pleuropneumoniae Bacterial Ghost Loaded With Pasteurella Multocida OmpH Gene Vaccine

Porcine contagious pleuropneumonia which is caused by Actinobacilluspleuropneumoniae, together with Porcine infectious atrophic rhinitic and Swine plague whichare caused by pasteurella multocida are common respiratory infectious disease in swineindustry, those swine diseases are always infected together. The construction of respiratorytract of swine infected with above diseases are damaged, which make infected pigs easy to getinfected by other respiratory pathogens, thus caused great economic loss to the world swineindustry, its necessary to develop a new combined vaccine to prevent above diseases.In this research, pCDNA-ompH gene vaccine was successfully constructed by outmembrane protein H of Pm A, and loaded into App BG to construct a combined vaccine, itsimmunological protective effectives on mice was evaluated through challenge experiment, theresults provided experimental basis for its clinical application.In the experiment, kunming mice were divided into4groups,3groups were immunizedwith App BG, pCDNA-ompH and App BG loaded with pCDNA-ompH respectively, the lastgroup was control. Mice were immunized3times with2weeks interval, serum were isolatedfrom tail blood every1weeks after immunization, specific antibody were tested by indirectELISA; mice were challenged with minimum lethal dose of bacterial cultures of App I/Pm D2weeks after the last immunization, challenged mice were observed for1week, died miceduring challenge were necropsied and their heart, liver, spleen, lung and kidney were sampledfor pathologic analysis; the number of live mice in each group were statisticed1weeks afterchallenge, the live mice were dissected, their blood were collected for antibody testing, andtheir heart, liver, spleen, lung and kidney were sampled for pathological analysis.After challenged with App I, mice showed loss of appetite, depressed, rough hair, anddyspnea, mice from control group were died totally, there was1dead from App BG groupand no dead from group of bivalent vaccine of App BG loaded with pCDNA-ompH genevaccine, protective rate of App BG and bivalent vaccine to App I was90%and100%respectively. After challenged with Pm D, mice showed loss of appetite, messy hair, dyspnea,diarrhea and slow reaction, there were3mice died from group of pCDNA-ompH,1deadfrom group of bivalent vaccine, mice from control group were died totally, protective rate ofpCDNA-ompH gene vaccine and combined vaccine to Pm D was70%and90%respectively.Gene vaccine constructed with ompH from Pm A could provide cross protection to Pm D. Pathological slice analysis showed that there were serious congestion of lung and liver of themice died during the challenged with App I, coagulative necrosis of lung of mice from controlgroup; there were no obvious lesion or slight lesion from mice from App BG group andcombined vaccine group. Mice died of challenge with Pm D showed retention, necrosis andvesicular degeneration of the kidney, thickened pulmonary mesenchyme, congestion andhemorrhage and inflammatory cell infiltration of the lung, live mice showed slighthemorrhage of the kidney and slight congestion of the lung, no obvious lesions of otherorgans. Contrasted with the antibody tire of mice before, after immunization, and afterchallenge, antibody level of bivalent vaccine group were slightly higher than App BG groupand pCDNA-ompH group.The challenge results indicated bivalent vaccine is practicable, the present result providedexperimental basis for further evaluation of their immunological protective effects to porcinecontagious pleuropneumonia, porcine infectious atrophic rhinitic and swine plague on swine.