The Study Of Transferrin-binding Protein A Gene On Protective Immunity In Piglets

Haemophilus parasuis is a pig respiratory tract often in bacteria, pig leather Las Jakob disease (Glasser's disease) pathogens. In recent years, caused by the HPS to swine fibrinous polyserositis, arthritis, meningitis, breathing difficulties, high fever and high mortality rates of infectious disease characterized by a rising trend year by year. The disease has become one of the most serious effects of the global pig industry bacterial infectious diseases, to the pig industry has brought significant economic losses. In the control aspects of Haemophilus parasuis disease, usually drug prevention and treatment and vaccinations, However, long-term heavy use of antibiotics to promote the gradual broadening spectrum of HPS resistance, multi-drug resistance is becoming more severe; and numerous HPS serotype, virulence and pathogenicity differences among strains are large, and the lack of each other effective cross-protection, resulting in the protective effect of HPS inactivated vaccine is very limited.HPS transferrin binding proteins (TbpA) not only has a good immune activity and guinea pigs have a good immune protection and cross-protective immunity effect.In this study, a recombinant protein TbpA and serotype 13 type HPS inactivated whole-cell vaccination of piglets, by detecting antibodies after immunization levels and cytokine levels piglet, piglet feed intake, rectal temperature, mental state and observed after poison attack mortality, and histological observation to investigate the immune protection TbpA protein on piglets, research Haemophilus parasuis disease prevention and control and HPS novel subunit vaccines provide a theoretical basis.First, Select about 15 HPS antibody negative 42 days old Yorkshire piglets, by Reed-Muench method for the determination of the median lethal dose 13 type HPS.Second,Select 25 about 14 days old Yorkshire HPS seronegative piglets were randomly divided into five groups (numbered A, B, C, D, E), n=5. A, B two injection TbpA, doses of 2mg, lmg; group C 13 Type HPS injection whole cell inactivated vaccine 1mL; D and E were injected with PBS 1mL; adjuvants are Freund's adjuvant, inoculation methods are the neck by intramuscular injection. Total third immunization, immunization were 14 days interval. A Free and two free for 14 days,10 days after the third immunization were collected blood serum was separated. ELISA was used to detect antibody levels, commercialized ELISA kit Th1, Th2-type cytokines. Type 13 was measured using the median lethal dose HPS Reed-Muench method. Three free for 10 days with 13 type HPS strains 7LD50 dose of piglets peritoneal attack drug, measured immune protection, and each group of pigs lung and spleen histopathological observation.The results showed that after a free, protein immunohistochemistry, whole cell inactivated vaccine group antibody levels and cytokine levels relative to the control group, the difference was not significant (P> 0.05); after the second immunization, protein antibody levels and cell immunohistochemistry factor levels relative to the control group had no significant difference (P> 0.05), while whole cell inactivated vaccine group was significantly higher antibody levels (P<0.05); after the third immunization, protein immunohistochemistry, whole cell inactivation antibody levels and cytokine levels Vaccine group are significantly higher (P<0.05), and the antibody levels were significantly higher than Immunohistochemical two free antibody levels (P<0.05). The first 10 days after the third immunization with HPS serotype 13 strain 7LD50 doses of A, B, C, D four piglets abdominal cavity after infection, A, group C piglet survival rate was 100%, group B piglet survival rate 40%, D group piglet survival rate is 0%. A, piglets difference C, E and group B piglets surviving degree of pathological changes in group D and group B pigs lung and spleen tissue samples of dead obvious. The results showed that, HPS of TbpA protein piglets capable of generating protective immunity, which 2mg dose immunization, immunization three times, Inactivated whole cell vaccine for homologous strain protective immunity poison attack the same 100%.