Expression of complement factor H binding immunoevasion proteins in Borrelia garinii isolated from patients with neuroborreliosis.
The Lyme disease-pathogen Borrelia burgdorferi binds the complement inhibitor factor H (FH) to its outer surface protein E- (OspE) and BbA68-families of lipoproteins. In earlier studies, only serum-resistant strains of the genospecies B. burgdorferi sensu stricto or B. afzelii, but not serum-sensitive B. garinii strains, have been shown to bind FH. Since B. garinii often causes neuroborreliosis in man, we have readdressed the interactions of B. garinii with FH. B. garinii 50/97 strain did not express FH-binding proteins. By transforming the B. garinii 50/97 strain with an OspE-encoding gene from complement-resistant B. burgdorferi (ospE-297), its resistance to serum killing could be increased. OspE genes were detected and cloned from the B. garinii BITS, Pistoia and 40/97 strains by PCR and sequencing. The deduced amino acid sequences differed in an N-terminal lysine-rich FH-binding region from OspE sequences of resistant strains. Recombinant B. garinii BITS OspE protein was found to have a considerably lower FH-binding activity than the B. burgdorferi sensu stricto 297 OspE protein P21 (P21-297). Unlike bacteria that had been kept in culture for a long time, neurovirulent B. garinii strains from neuroborreliosis patients were found to express approximately 27-kDa FH-binding proteins. These were not recognized by polyclonal anti-OspE or anti-BbA68 antibodies. We conclude that B. garinii strains carry ospE genes but have a decreased expression of OspE proteins and a reduced ability to bind FH, especially when grown for prolonged periods in vitro. Recently isolated neuroinvasive B. garinii strains, however, can express FH-binding proteins, which may contribute to the virulence of neuroborreliosis-causing B. garinii strains.
Alitalo
Antti
A
Department of Bacteriology and Immunology, Haartman Institute and Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.
Meri
Taru
T
Comstedt
Pär
P
Jeffery
Luke
L
Tornberg
Johanna
J
Strandin
Tomas
T
Lankinen
Hilkka
H
Bergström
Sven
S
Cinco
Marina
M
Vuppala
Santosh R
SR
Akins
Darrin R
DR
Meri
Seppo
S
D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D015748:Borrelia burgdorferi Group / Q000472:pathogenicity* / Q000502:physiology*; D017242:Complement Factor H / Q000276:immunology / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008074:Lipoproteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D020852:Lyme Neuroborreliosis / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D020349:Surface Plasmon Resonance
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008074:Lipoproteins; C084998:OspE protein, Borrelia burgdorferi; D017242:Complement Factor H