A novel pore-forming hemolysin protein in Leptospira species / 中国人兽共患病学报

Hemolysins of Leptospira interragans have been shown to be the virulence factor in the pathogenesis of leptospirosis and 10 potential hemolysin genes were charecterized by genomic annotation of L.interrogans serovar.Lai strain 56601. In the present study, the LA0202 gene supposed to encode one of the new potential hemolysin was cloned and the protein encoded was purified. The purified protein was shown to have highly hemolytic activity as demonstrated on the sheep blood agar plate. It was also confirmed that the LA0202 protein-mediated hemolysis on sheep erythrocytes was osmotically protected by PEG6000. Meanwhile, this protein could induce pore formation on sheep erythrocytes and cause damages on the membrane of human L-02 liver cells. In addition, it could induce apoptosis of human L-02 liver cells after treatment of cells with this protein for 24 hours. It is evident that LA0202 protein acting as a pore-formong hemolysin can induce cytotoxic damage on mammalian cells.

The immune responses induced by a recombinant DNA vaccine for leptospirosis:pVAX1/LipL21-LipL32 / 中国人兽共患病学报

Two highly conserved and with abundant quantity of lipoproteins in outer membrane of pathogenic species,but not in saprophytic species of leptospira ,LipL32 and LipL21,were selected to construct the fusion gene DNA vaccine pVAX1/LipL21-LipL32,and its ability to induce immune responses in BALB/c mice inoculated with this recombinant DNA vaccine was investigated in the present study.Expression of the fusion-protein LiPL21-LiPL32 was demonstrated in HEK293 cells following transfection with the fusion gene DNA vaccine and the immune responses induced after intramuscular inoculation with this DNA vaccine in BALB/c mice was then evaluated by microscopic agglutination test (MAT),meanwhile the ELISA assay was used to detect the cytokines induced.It was demonstrated that significant level of specific antibodies agglutinating antigens of Leptospira interrogans could be detected by MAT after DNA vaccine inoculation.The production of cytokines IL-10 and TNF-β in mice inoculated with DNA vaccine pVAX1/LipL21-LipL32 was significantly increased in comparison with that of the group inoculated with pVAX1 alone.These results indicate that the recombinant DNA vaccine pVAX1/LipL21-LipL32 may be of potential value to design and develop new generation of vaccines against leptospirosis.