Epitope Mapping of BmpA and BBK32 Borrelia burgdorferi Sensu Stricto Antigens for the Design of Chimeric Proteins with Potential Diagnostic Value

Lyme disease is a tick-borne zoonosis
caused by Gram-negative bacteria
belonging to the Borrelia burgdorferi sensu lato (s.l.) group. In this study, IgM- and IgG-specific linear
epitopes of two B. burgdorferi sensu
stricto (s.s.) antigens BmpA and BBK32 were mapped using a polypeptide
array. Subsequently, two chimeric proteins BmpA-BBK32-M and BmpA-BBK32-G
were designed to validate the construction of chimeras using the identified
epitopes for the detection of IgM and IgG, respectively, by ELISA.
IgG-ELISA based on the BmpA-BBK32-G antigen showed 71% sensitivity
and 95% specificity, whereas a slightly lower diagnostic utility was
obtained for IgM-ELISA based on BmpA-BBK32-M, where the sensitivity
was also 71% but the specificity decreased to 89%. The reactivity
of chimeric proteins with nondedicated antibodies was much lower.
These results suggest that the identified epitopes may be useful in
the design of new forms of antigens to increase the effectiveness
of Lyme disease serodiagnosis. It has also been proven that appropriate
selection of epitopes enables the construction of chimeric proteins
exhibiting reactivity with a specific antibody isotype.