Predicton and identification of antigenic epitopes in genus-specific outer membrane proteins OmpL1 and LipL21 of Leptospira interrogans / 中华微生物学和免疫学杂志

Objective To screen the efficient antigenic epitopes in genus-specific envelope proteins OmpL1 and LipL21 of Leptospira interrogans for further development of multiple antigenic peptide (MAP)vaccine.Methods Based on bioinformatic technique,the combined epitopes of T and B lymphcytes in OmpL1 and LipL21 molecules were screened.Nucleotide fragments of each epitopes were amplified by PCR and then constructed their phage display systems.Using antisera against rOmpL1,rLipL21,L.interrogans serogroup Icterohaemorrhagiae strain Lai and leptospirosis patients' sera as the first antibodies.respectively,Western blot assays were performed to determine the immunoreaetivity and reactive ability of the epitopes with different antisera.Resuits Four combined epitopes of OmpL1 and two combined epitopes of LipL21 were selected out by the predicting procedure.All the amplified epitope fragments were accurately inserted into the region at N end of phage PⅢ protein and successfully expressed.All of the antisera could recognize each of the epitopes.Based on the results of Western blot,the two LipL21 epitopes at 97-112 and 176-184 showed similar strong hybridization signals with any of the antisera,and the hybridization signals of four OmpL1 epitopes with the three antisera were 173-191,87-98,297-320 and 59-78,from strong to weak.Conclusion The six combined epitopes in this study are efficiently antigenic.And the epitopes at positions 97-112 and 176-184 in LipL21 as well as the epitopes at position 87-98 and 173-191 in OmpL1 have a potential for developing leptospiral MAP vaccine.

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.