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Evaluation of the interaction of Leptospira interrogans proteins with host components by constructing recombinant Leptospira biflexa

Grant number: 18/09652-4
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): September 01, 2018
Effective date (End): August 31, 2021
Field of knowledge:Biological Sciences - Microbiology - Applied Microbiology
Principal Investigator:Ana Lucia Tabet Oller Do Nascimento
Grantee:Leandro Toshio Kochi
Home Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
Associated research grant:14/50981-0 - Search for surface proteins among the genome sequences of Leptospira interrogans: functional and immunological characterization to understanding mechanisms involved in the bacterial pathogenesis, AP.TEM


Leptospirosis is an acute infectious disease of worldwide importance and considered as one of the neglected tropical diseases. The disease is caused by pathogenic bacteria of the genus Leptospira and affects several mammals, including man. To date, there is no effective vaccine against the disease, which is of major socioeconomic importance in tropical developing countries. The fight against leptospirosis becomes more difficult since the biology of the pathogen is not yet fully understood. Several research groups seek to better understand the mechanisms of pathogenicity and development of an effective vaccine by screening potential candidates, which are generally outer membrane proteins conserved in different pathogenic leptospire species. This characterization is generally done through the expression and purification of recombinant proteins, which often may not mirror what occurs in vivo. Thus, developing recombinant strains has been a viable alternative. In this sense, the present project proposes the construction of L. biflexa (saprophytic) recombinant strains expressing the proteins of interest, encoded by the L. interrogan genes LIC11711 and LIC12587, whose recombinant counterparts demonstrated significant interactions with host components in vitro . The expression of the proteins in the saprophytic strain will allow the functional validation of these as possible ligands to components of the host and the understanding of the roles in the mechanisms of pathogenicity and possible vaccine candidates. Initially, constructs will be made using the plasmid pMaOri and the genes of interest, previously fused with the promoter of the lipL32 gene. L. biflexa will be transformed with the plasmid constructs for expression of the proteins. Cell localization assays and interaction assays of recombinant L. biflexa with host components will be performed. Hamsters will be immunized with the recombinant proteins or the recombinant bacteria and challenged for evaluation of the immune protection provided by these vaccine elaborations.