Characterization of the heat shock response and identification of heat shock protein antigens of Borrelia burgdorferi.

The heat shock response of Borrelia burgdorferi B31 cells was characterized with regard to the heat shock proteins (Hsps) produced. Five to seven Hsps were detected by sodium dodecyl sulfate-gel electrophoresis and fluorography of proteins from cells labeled with [35S]methionine after shifts from 33 degrees C to 37 or 40 degrees C or from 20 degrees C to 33, 37, or 40 degrees C. Analysis of [35S]methionine-labeled Hsps by two-dimensional electrophoresis and autoradiography revealed 12 Hsps. Western immunoblot analysis with antisera to highly conserved Escherichia coli and Mycobacterium tuberculosis Hsps revealed a single 72-kilodalton (kDa) protein band that reacted with antibodies to E. coli DnaK and with antibodies to the M. tuberculosis 71-kDa Hsp homolog of E. coli DnaK. Two proteins with apparent molecular masses of 66 and 60 kDa reacted with antibodies against the M. tuberculosis 65-kDa Hsp homolog of E. coli GroEL. Human immune sera collected from patients with Lyme disease reacted with both the 66-kDa Hsp and the 60-kDa Hsp but failed to react with the 72-kDa Hsp. These data are discussed with regard to the possibility that host recognition of highly conserved epitopes of GroEL homologs of B. burgdorferi may result in autoimmune reactions causing arthritis and other pathologies.