Study Of The Molecular Mechanism And Effect Of Mast Cell Response In Mice Brucella Infection

The aim of this experiment was to study the molecular mechanism and effect of mastcells in mice response brucella infection. In this experiment, in vivo and in vitro testmethods was combined by adopted, research the changes of brucella infection, such as thechanges of MC in mice, the changes of TLRs expression, the changes of various cytokinesin serum, and its influence to the distribution of DCs. In vitro experiments, the MC P815cells was cultured on the culture plate, then infected the MC separately with brucella S2strains and brucella S2WboA-/-strains of which was in multiplicity of infection (MOI)1:100, and established the normal control group (only the culture medium), when infected12h,24h, we can collected the cells, RT-PCR was used to test the changes ofTLR2,TLR4,TLR8,TLR9. The results of RT-PCR showed that the TLRs in mRNA levelhas a change after the brucella infected, was higher than the normol group, basically thegroup of brucella S2strains infected was all above the group of brucella S2WboA-/-strainsinfected, especially the expression of TLR4, this may be related to the brucella S2WboA-/-strains does not produce LPS. This change had improved the function of antigen presentingcells, promoted the secretion of various cytokines, thus to enhance the body’s ability tofight the infection of brucella.In vivo experiments,150female BALB/c mice which8weeks old were randomlydivided into5groups, each group30. A is for the PBS control group; B is for the groupinfected by brucella S2strains; C is for the group infected by brucella S2WboA-/-strains;D is for the eliminate MC group infected by brucella S2strains; E is for the eliminate MCgroup infected by brucella S2WboA-/-strains. After vaccinated1h,6h,12h,24h,48h,72h respectively, collected the peripheral bloods, separated the serum, ELISA was used totest the changes of TNF-α、IFN-γ、IL-4in serum; cervical dislocation method was usedto killed the mice, collected the vagina、uterus、iliac lymph nodes, made paraffin section,toluidine blue staining to observed the MC; immunohistochemical observed of thedistribution of DCs in vagina mucosa. The results of ELISA showed that the expression ofTNF-α, IFN-γ, IL-4in the serum were increased after brucella infected, leds to asignificant inflammation, this prompted that the body may initiated a predominantly Th1immune, and complement with Th2immune responses to fight the infection. The results of paraffin section showed that the numbers of MC were no obvious rised, more and less, thismay be associated with individual differences; immunohistochemistry showed that ininfected6h,12h the numbers of DCs were significantly increased, this prompted that theDCs may be migrated into lymph nodes after the stimulate of brucella, matured andactivated the initial T cells, and activated the Th1immune.Conclusion: Anti-c-kit antibody was eliminated the MC successfully in the vagina,uterus, lymph node of mice; MC were regulated the expression of TLRs to responsed thebrucella infection, at the same time, we had been clear about the role of LPS in MC toidentify the brucella; MC could secreted and regulated different cytokines, such as TNF-α,IFN-γ, IL-4, etc., to started the Th1/Th2immune, predominantly Th1immune, Th2immune is complementary, participated the immune response of brucella infection; aftereliminate the MC, the body may be resisted the infection of brucella through other ways orother mechanisms; DCs may be the antigen presenting cells of brucella, the MC may besecreted some active substances, such as TNF-α, to adjusted the antigen presentingfunction of DCs; the brucella S2strains compared with brucella S2WboA-/-strains,although the toxicity is bigger, but the immune effect is better.