SBIR Phase I: Recombinant Multiepitope Mosaic Protein Design for Urine-based Diagnosis of Leptospirosis

This Small Business Innovation Research (SBIR) Phase I project aims to develop recombinant monoclonal antibodies using "mosaic" antigens derived from Leptospira spp proteins identified in the urine of clinical patients. The mosaic antigens are designed to artificially combine important antigenic epitopes in order to maximize the coverage of potential epitopes in one structure and to provide broader coverage than those afforded by multiple synthetic peptides. Our approach involves the use of computational biology and bioinformatics to create, score, and select "mosaic" antigens from Leptospira spp. Antigenic properties of the mosaic antigens are evaluated by indirect ELISA using a panel of well-characterized human sera from clinical patients and apparently healthy individuals. We will then use recombinant DNA and protein engineering techniques to derive cognate chimeric proteins, followed by the generation of recombinant epitope-specific monoclonal antibodies that target potential epitopes (rather than a few dominant epitopes) generated from the "mosaic" protein. The diagnostic potential of the recombinant antibody is evaluated by immunoblotting and ELISA using leptospirosis specimens from early and convalescent phases of the illness. The broader impact/commercial potential of this project, if successful, will be the development of a rapid, non-invasive, one-step, multiplex test that will have general applicability in the timely diagnosis of a complement of febrile illnesses, including leptospirosis. This is aimed at tropical and subtropical countries where the disease incidences are higher and where current tools are mostly inadequate. Early leptospira diagnosis is essential because antibiotic treatment is most effective when initiated early in the course of the disease. Current diagnostic tools are unsuitable for use in resource-limited settings especially in the tropical regions where other similar acute febrile illnesses are common. It expands the multiplex diagnostic test panel we are presently developing by iterative expansion.