[Cloning and expression of leptospiral protective antigen gene OmpL1 in BCG]

This study was intended to produce a new living vaccine against leptospirosis using BCG as vector. Leptospiral outer envelop antigen gene OmpL1 was amplified from the genome of pathogenic leptopira serova Lai 017 by PCR, and cloned in E. coli-BCG shuttle plasmid pY6002. Recombinant plasmids were isolated by dot blotting with Digoxigeninlabeled OmpL1 gene. After transforming the recombinant plasmids in BCG (Shanghai strain) by electroporation, the genomic DNA of all 21 transformants were prepared and hybridized with OmpL1. It showed that 6 of the 21 transformants were recombinants in which the OmpL1 gene had been integrated into the genome of BCG. By immunoblotting with OmpL1 infected rabbit antiserum, which was preabsorbed to remove antibody against E. coli and SPA-HRP, three recombinants, pLI1, pLI2 and pLI3, were detected to express OmpL1 protein. The ability of expression is in the order of pLI2 > pLI1 >> plI3. These studies provide the possibility of further research on the development of highly efficient recombinant vaccines against leptospirosis.