Study Of The Mutual Interaction Of HPS Serotypes 4 And 13 Of Transferrin-bingding Protein A Of Guinea Pig

Haemophilus parasuis can cause the under certain conditions pigs,especially in weanling pigs and nursing pigs have Haemophilus influenzae disease which characterized by multiple serosa,arthritis and meningitis.Drug prevention,such as vaccination method is often used to control of Haemophilus parasuis disease,however,all kinds of antibiotics unreasonable application of drugs and a large number of long-term research and development of new antibiotics in HPS resistance are increasing;at the same time as the HPS have complex serotype,and has obvious place,currently available on the production of inactivated vaccine or rarely can not produce cross protection,therefore need to develop a new vaccine according to various serotype strains infection have a lasting immune protection and with cross protective immunity.Our previous study showed that HPS serotype 13 transferrin binding protein A(TbpA)not only for the same type of serum challenged guinea pigs had a good immune activity,but also on the different serotypes(serotype 4 HPS)to provide cross protection force,but other blood type TbpA can provide cross immunity protection against different serotypes is not clear,so this study based on previous studies,with the expression of HPS serotypes 4,TbpA type 13 in guinea pigs,detection of immune TbpA in guinea pig serum antibody level and cytokine tumor necrosis factor alpha(TNF-α,IFN-γ,IL-2,IL-5,IL-8,MCP-1)levels in guinea pigs after infection by mental state and food intake,mortality,autopsy and pathological sections were made,the interactive immune protection of recombinant TbpA research on HPS attack of the guinea pigs The study has laid the foundation for the study of whether HPS of TbpA has good cross immunity protection to this animal(piglet).First,Reed-Muench(cumulative method)was used to determine the median lethal dose(LD50)of HPS serotypes 4 and 13 against HPS antibody negative guinea pigs.HPS antibody negative female guinea pigs followed by screening 54 healthy and40 days of age,each group were randomly assigned to 6,a total of 9 groups,A1,A2 group with 100μg immune HPS serotype 4 TbpA.B1,B2 group with 100μg immune HPS serotype 13 TbpA.C1 and C2 groups were injected with 200μL PBS as the control group.A3,B3 and C3 groups were injected with 200μL PBS as the blank control;the adjuvant was Freund’s adjuvant,and the subcutaneous injection of the back was performed with an interval of 20 days.Blood samples were taken from the heart at 10 days after each immunization,and the levels of antibodies and cytokines(IL-2,IL-5,IL-8,IFN-,TNF-,MCP-1)were detected in guinea pigs after immunization.21 days after the second immunization,A1,B1,C1 to HPS serotype 4absolute lethal dose of poison attack,A2,B2 and C2 were challenged with HPS serotype 13 absolute lethal dose,A1,B1,C1 injected with PBS,to observe and calculate the rate of immune protection at the same time,observed histopathological characteristics of guinea pigs discussion on the interaction between syndrome,protective immunity of HPS TbpA infection in guinea pigs.The results showed that the immune serum HPS serotype 4、13 TbpA of guinea pigs after antibody levels in serum were increased after two free were increased significantly,but no significant differences between them;in addition to MCP-1,5kinds of cytokine levels were significantly increased after the two immunization,and the difference between the two immunization significantly.But the immune serum serotype between 4 and 13 TbpA group had no significant difference;HPS serotype 4immunization group challenge protection on the same serotype and different serotypes of HPS were 66.7% and 50%;HPS serotype 13 immunization group challenge protection on the same serotype and different serotypes of HPS rate was 81.3% and50%;control group and blank control group survival of guinea pig guinea pigs showed no obvious gross lesions and pathological changes,the challenge group of death in guinea pigs lung hemorrhage and necrosis,liver surface fibrin exudation,thoracic cavity,abdominal effusion,pleural adhesions,brain Bleeding and other visible lesions,pathological observation showed that after the attack,the lungs,spleen and liver of guinea pigs died of slight inflammatory cell infiltration or slight bleeding.The results show that the HPS serum serotype 4、 13 TbpA protein to the same type and different serotype of HPS interaction provide protective immunity;immune protection of HPS serotype 13 TbpA of the same serotype was higher than that of serotype 4,serotype HPS 4 and 13 TbpA of different serotypes of HPS virus attack.The differences in disease free guinea pigs protection force was not significant.