CROSS-REACTIVE ANTIGENIC DOMAINS OF THE FLAGELLIN PROTEIN OF BORRELIA-BURGDORFERI

The p41 flagellin of Borrelia burgdorferi is the most common antigen r ecognized by serum of patients with Lyme borreliosis. This antigen sha res amino acid homology, particularly in the amino and carboxy termini , with periflagellar antigens found in other microorganisms including Treponema pallidum. We cloned and expressed the p41 open reading frame in Escherichia coli and expressed it both as TrpE fusion and full-len gth unfused proteins. Also, we generated deletion constructs of variou s portions of the gene. Sera from patients with late Lyme borreliosis and secondary syphilis were used to identify the recombinant proteins by immunoblot analysis. Sera from 26 patients with Lyme borreliosis, 2 0 with secondary syphilis and 10 controls were used to identify cross- reactive domains of the B. burgdorferi flagellin. The variable region (amino acids 131-234) of the protein was recognized by 59% (15/26) of patients with late Lyme borreliosis compared to 30% (6/20) of patients with secondary syphilis and no (0/10) control patients. It appears th at cross-reactive epitopes between B. burgdorferi and T. pallidum exte nd to the variable region of the flagellin.