| Porcine infectious pleuropneumonia is a respiratory infectious disease with strong infectious andhigh mortality rate, the mortality rate of acute cases can achieved80-100%. This kind of disease iscaused by Actinobacillus pleuropneumoniae (APP), this bacteria can easily cause damage of thebody lungs, combined with the appear of drug-resistant strains, it is difficult to cure those infectedpigs, and this can bring huge economic losses in pig industry all over the world. However,serotype of APP is as many as fifteen and among the main serotype lacks of cross immunityprotection, this leads to the research progress of vaccine is very slow. Up to now, there is nocommercialization of the vaccine in the world which is broad-spectrum and can offer crossprotection for various serotypes. Propionibacterium acnes(PA) is a gram-positive bacteria whichis widely exists in normal person and animals’ body surface, body cavity and lesions, there’s noreports that this bacteria can cause disease in animal clinical. PA can adjust the immune, can beused as adjuvant, and it has antitumor activity, so the research of immune regulation and antitumoractivity about PA and its’ extract is a hot issue now.After the test of immune and poison in mice and piglets, we found that PA can preventinfection from APP. In order to find the gene of cross immunity protection between the mainserotypes of APP, we screened the differential gene of main serotypes of APP in2007, and thenwe accidentally found that there is a very strong cross immune response between PA and APP.Though we had preliminary evidenced that PA can specific prevent against APP infection andgive priority to humoral immunity, but there’s no systemic and deep going research about immuneresponse and protection of PA, so further development and utilization are limited.In order to clarify the mechanism of action of PA against APP infection, and promote theresearch of pleuropneumonia vaccinum, we used the activated and inactivated PA bacterial strainin mice immune, then we detected the antibody level and antibody type of immune response; weused fluorescence activated cell sorting (FACS) to analysis the type and proportion of lymphocyte in lung cells suspension; determined the survival situation of APP poisoned mice under differentlevels of antibodies. Comprehensive analysis the type of PA immune response, clarified thecorrelation between the type and level of PA antibody of immune response and the APP effect ofinfection of prevention mice. At the same time, we did immunofluorescence test and antibodies toadjust test to make sure that antibodies can play a role in prevent infection of APP; we built B celldepletion model of mice, implement poison attack after immune of PA, then inspect the ability toresist infection when the antibody levels is low, so we could authenticate reverse the effect ofanti-PA antibodies.Experiments show that PA living bacterium immune antibody levels is higher thaninactivated bacteria obviously, as well as its’ protective effect, the best living bacterium does is2~*10~8CFU. Immune under the best conditions, the mice’s survival rate after APP1poison attack ispositively related to the mice’s antibody levels after PA immunization and the PA inducedantibodies can be combined with APP1in vitro. When add10%hyper-immune serum resistanceto PA, it can significantly improve phagocyte’s phagocytosis of APP1, there is no differencebetween promote phagocytosis and APP serum resistance effect, this proves that the antibodiesinduced by PA can promote phagocyte’s phagocytosis of APP1. we built B cell depletion model ofmice successfully, when compared with PA immunization and controls in this model, the level ofantibody is significantly low, and protection rate is significantly reduce, this shows that thespecificity of PA immune induced B cells and the antibodies plays a very important role in theprevention of infection of APP.This research enriched the use of PA bacterial strain, created a new situation about the research ofAPP prophylactic vaccine, it clarified the mechanism of action when PA prevent the happen ofpleuropneumonia. All of this provide beneficial theoretical basis for the research ofpleuropneumonia vaccine and heterologous vaccine... |
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