The relapsing fever spirochete Borrelia hermsii contains multiple, antigen-encoding circular plasmids that are homologous to the cp32 plasmids of Lyme disease spirochetes.
Borrelia hermsii, an agent of tick-borne relapsing fever, was found to contain multiple circular plasmids approximately 30 kb in size. Sequencing of a DNA library constructed from circular plasmid fragments enabled assembly of a composite DNA sequence that is homologous to the cp32 plasmid family of the Lyme disease spirochete, B. burgdorferi. Analysis of another relapsing fever bacterium, B. parkeri, indicated that it contains linear homologs of the B. hermsii and B. burgdorferi cp32 plasmids. The B. hermsii cp32 plasmids encode homologs of the B. burgdorferi Mlp and Bdr antigenic proteins and BlyA/BlyB putative hemolysins, but homologs of B. burgdorferi erp genes were absent. Immunoblot analyses demonstrated that relapsing fever patients produced antibodies to Mlp proteins, indicating that those proteins are synthesized by the spirochetes during human infection. Conservation of cp32-encoded genes in different Borrelia species suggests that their protein products serve functions essential to both relapsing fever and Lyme disease spirochetes. Relapsing fever borreliae replicate to high levels in the blood of infected animals, permitting direct detection and possible functional studies of Mlp, Bdr, BlyA/BlyB, and other cp32-encoded proteins in vivo.
Stevenson
B
B
Department of Microbiology and Immunology, University of Kentucky College of Medicine, Lexington, Kentucky 40536-0298, USA. bstev0@pop.uky.edu
Porcella
S F
SF
Oie
K L
KL
Fitzpatrick
C A
CA
Raffel
S J
SJ
Lubke
L
L
Schrumpf
M E
ME
Schwan
T G
TG
D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics*; D001483:Base Sequence; D001898:Borrelia / Q000235:genetics* / Q000276:immunology*; D025065:Borrelia burgdorferi; D015748:Borrelia burgdorferi Group / Q000235:genetics* / Q000276:immunology*; D015342:DNA Probes / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D000942:Antigens, Bacterial; D015342:DNA Probes; D004269:DNA, Bacterial