Preliminary Study On Multicomponent Subunit Vaccine Of Bovine Mycobacterium Avium Subsp. Paratuberculosis

Paratuberculosis is a serious infectious disease caused by Mycobacterium avium subsp Paratuberculosis(MAP).It occurs in all countries of the world and is also the most common disease in our country.For the control of the disease,only a few countries use post-quarantine culling strategies,but this strategy does not apply to all countries and regions.Currently,there is only commercial inactivated vaccine in the world,which can reduce the excretion of pathogens,but it can not completely block the infection of the MAP.Therefore,it is necessary to develop the efficient vaccines.This study explored the efficacy of two multi-component(MAP culture supernatant,MAP cell wall)vaccines and compare immune enhancement effect about Ghost adjuvants and Incomplete Freund Adjuvant(IFA)on these multi-component vaccines.At the same time,MAP inactivated vaccine +aluminum salt adjuvant were compared and mice immunized after challenge were evaluated in order to screen out the vaccine with the best immunity.The experimental results showed that the MAP cell wall group could produce a high level of immune titer after the first immunization.After econd immunization and third immunization,the antibody titer keep rising continuously and the titer was significantly higher than that of the MAP culture supernatant and MAP inactivated vaccine group.In the MAP culture supernatant group,the titers were significantly higher than those in the PBS control group after the second immunization,while the MAP inactivated vaccine group was significantly higher than that in the PBS control group after the third immunization.The secretion of IL-2,IFN-?,IL-4 and IL-10 in the MAP cell wall group was significantly higher than that in the MAP culture supernatant group and the MAP inactivated vaccine group after the time of the third immunization.The secretion of IL-2,IFN-?,IL-4 and IL-10 in MAP culture supernatant group and MAP inactivated vaccine group was significantly higher than that in PBS control group.It showed that the immune response induced by MAP cell wall group was stronger than MAP culture supernatant group and MAP inactivated vaccine group.The results of challenge experiment showed that the amount of MAP in the liver,spleen and small intestine of MAP cell wall group was less than that of MAP culture supernatant group and MAP inactivated vaccine group,and the MAP cell wall group containing IFA adjuvant is better than Ghost group after the third immunization.The results showed that MAP cell wall group was better than that of MAP culture supernatant group and MAP inactivated vaccine group.This study lays the foundation for the development of a new vaccine for paratuberculosis.