| Leptospirosis is an acute and important zoonosis of worldwide distribution,which caused by pathogenic Leptospira interrogans belonging to the genusLeptospira. The prevalence of the disease on a global scale leads to a serious threat tothe health of human and animal husbandry development. Engaged in outdooroccupation, recreational activity, flooding, close contact with animals andother infection factors, will increase the risk of transmission to humans. Leptospirosishas a variety of clinical syndromes, including subclinical, self--limiting, anicteric,fever and even severity to death. Leptospires are widely distributedin tropical, subtropical and temperate regions of urban and rural areas. In the past fewdecades, the changing of epidemiology model emphasizes the importance of thedisease as a public health problem. The annual report of leptospirosis has more than500,000cases, the mortality rate of more than10%.It is an imminent task for our country to prevent and control leptospirosis,because we have been plagued by the outbreak of it for a long time, but theresearch progress has been made in the study of pathogenic mechanism andhost immune response is not very clear. Generally thought of from Leptospiraestablish infection to the formation of persistent colonization and immune evasion, itmainly relies on various membrane surface molecules (virulence factors) to invasionand adhesion of specific host cell. The number of Leptospira serotype is more than230due to the leptospiral LPS carbohydrate composition have differences. As a kindof immune protective antigen of Leptospira, LPS has been used to develop as avaccine, but the commercial inactivated whole cell vaccine or attenuated vaccine willproduce some toxic effects and it maintain the duration of immunity rely onstrengthen the immunity. LPS can not produce cross protection againstother serotypes. The current study showed that some outer membrane proteins (OMPs) ofpathogenic Leptospira have antigenic conservation among serovars such asOmpL1, LipL32, LipL41, LigA, LigB, Lp1454and others OMPs, therefore subunitvaccines have possible to instead of the whole cell inactivated vaccine for goodprospects it have Leptospira binds to the host extracellular matrix (ECM) bysurface adhesion. Lig proteins are rich and conservative among surface exposed outermembrane proteins, widely distributed in a variety of pathogenic serotypes. In this testwe select L.interrogans Autumnalis serovar Lin4genome as a template, amplifiedLigAcon, LigAvar, LigBcen1by PCR., Use prokaryotic expression vector pGEX-4T-1to construct recombinant plasmids pGEX-LigAcon, pGEX-LigAvar, pGEX-LigBcen1after sequencing and transformed into E.coli BL21(DE3) induce recombinantproteins. The soluble protein by affinity chromatography mixed with Freund’sadjuvant subcutaneous injection of3~4week old hamsters for trial group, calledrLigAcon, rLigAvar, rLigBcen1, rLigA (rLigAcon+rLigAvar), strengthenthe immunity after3weeks. The control PBS group and GST label group use thesame immune procedure. Evaluation of immune protection of recombinantproteins was observed by hamster model of survival rate and histopathology.The test results showed that these fusion proteins molecular wight were about89kDa(LigAcon),92kDa (LigAvar),68kDa (LigBcen1). Hamsters were immunizedwith recombinant proteins which have protective efficacy after challenge withL.interrogans Autumnalis serovar, and it has a significant difference (P<0.05)compared with the control group. Histopathological study showed that inflammationand hemorrhage condition of liver, renal, lung from survival hamsters improvedsignificantly. This study reflects immune protective effect of Lig proteins whichbelong to Leptospira interrogans genus specific protective antigen.. Leptospirainterrogans LigA gene has ability to resistant infection of the same serotype, thesepreliminary study provides experimental data for the further study of leptospirosissubunit vaccine. |
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