DEVELOPMENT OF RECOMBINANT ANTIGEN-BASED ELISA FOR THE DETECTION OF ANTI-TULAREMIA ANTIBODIES IN SWINE AND HUMAN SERA: A PILOT STUDY

To the present day, a Francisella infection is diagnosed by a mandatory combination of two methods: a screening Enzyme-linked Immunosorbent Assay (ELISA) and a confirmatory Western Blot (WB), both based on the use of Francisella tularensis subsp. holarctica lipopolysaccharides (LPS) as a capture antigen. The purpose of the present work was to obtain and assess three recombinant proteins (FTT1696, FTT0077, FTT0975) as antigens in an indirect ELISA (iELISA) with the final goal to replace the confirmatory WB. Cloning strategy in vector pASG103, expression in E. coli and purification of proteins using Strep-system are described in detail in this report. Sera with confirmed antibody titers against F. tularensis reacted with all three antigens, which make them suitable for the serological detection of F. tularensis in swine and humans.