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- Alitalo, Antti, et al.
(författare)
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Expression of complement factor H binding immunoevasion proteins in Borrelia garinii isolated from patients with neuroborreliosis.
- 2005
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Ingår i: Eur J Immunol. - 0014-2980. ; 35:10, s. 3043-3053
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
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| 3. |
- Pietikainen, Johanna, et al.
(författare)
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Binding of the complement inhibitor C4b-binding protein to Lyme disease borreliae
- 2010
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 47:6, s. 1299-1305
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Tidskriftsartikel (refereegranskat)abstract
- The Lyme disease spirochetes, Borrelia burgdorferi sensu stricto, Borrelia afzelii and Borrelia garinii. are tick-borne pathogens that can cause chronic disseminated infections. To survive in the human host borreliae need to evade the immune system. It is already well known that B. burgdorferi ss. and B. afzelii bind the complement (C) alternative pathway inhibitor factor H from serum using OspE and CRASP-1/Bba68 proteins to escape C attack. In the presence of natural antibodies and in chronic infections, when specific antibodies develop, borreliae have to protect themselves from antibody-induced classical pathway C attack. In this study we demonstrate binding of the classical pathway inhibitor, C4b-binding protein (C4bp), to three genospecies of B. burgdorferi sensu lato. Binding was strongest to B. garinii, which has been found to be the weakest factor H binder. The bacteria bound both purified I-125-labeled C4bp and C4bp from serum. Unlabeled C4bp competed for binding with I-125-C4bp, whereas BSA had no effect. Binding was salt-sensitive and inhibited by C4b and partially by heparin. C4bp maintained its cofactor activity for factor I in cleaving C4b when bound to the bacterial surface. Ligand blotting analysis of whole cell lysates and fractionated outer cell membranes of the bacteria suggested one major receptor of approximately 43 kDa (P43) for C4bp in B. garinii and B. burgdorferi sensu stricto. Binding of C4bp may thus allow Lyme disease borreliae to escape activation of the classical C pathway and allow chronic infections in humans even in the presence of specific antibodies. (C) 2009 Elsevier Ltd. All rights reserved.
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