Prokaryotic Expression Of Leptospira Interrogans GroEL Gene And Immunoprotection Of The Product In Hamsters

Objective:To generate a prokaryotic expression system of groEL gene of Leptospira interrogans serogroup Icterohaemorrhagia serovar Lai strain, and to determine the immunoprotective effect of recombinant expressed GroEL protein (rGroEL) in LVG hamsters.Methods:The groEL gene was amplified by high fidelity PCR and the amplification product was then sequenced. A prokaryotic expression system of the groEL gene was generated using routine genetic engineering technique. SDS-PAGE plus Bio-Rad Gel Image Analyzer was applied to examine the expression and dissolubility of rGroEL protein while Ni-NTA affinity chromatography was used to extract the expressed rGroEL. The immunoprotective rate in rGroEL-immunized LVG hamsters was determined after challenge with L. interrogans strain Lai. The cross agglutination titers of sera from immunized hamsters with different L. interrogans serogroups were detected using MAT.Results:The nucleotide and amino acid sequences of the cloned groEL gene were the same as those reported in GenBank. The generated prokaryotic expression system of groEL gene expressed soluble rGroEL. The immunoprotective rates of100and200μg rGroEL in LVG Hamsters were50.0%and75.0%, respectively. The sera from the rGroEL-immunized LVG Hamsters could agglutinate all the L. interrogans serogroups tested with different levels.Conclusions:The GroEL protein is a genus-specific immunoprotective antigen of L. interrogans and can be used to develop an universal genetically engineering vaccine of Leptospira.