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BIBTEX RIS

Pathogenic Leptospira Species Acquire Factor H and Vitronectin via the Surface Protein LcpA

2014; American Society for Microbiology; Volume: 83; Issue: 3 Linguagem: Inglês

10.1128/iai.02844-14

ISSN

1098-5522

Autores

Ludmila Bezerra da Silva, Lídia dos Santos Miragaia, Leandro Carvalho Dantas Breda, Cecília M. Abe, Mariana Costa Braga Schmidt, Ana Maria Moro, Denize Monaris, Jonas N. Conde, Mihály Józsi, Lourdes Isaac, Patrícia Antônia Estima Abreu, Angela Silva Barbosa,

Tópico(s)

Leptospirosis research and findings

Resumo

ABSTRACT Upon infection, pathogenic Leptospira species bind several complement regulators in order to overcome host innate immunity. We previously characterized a 20-kDa leptospiral surface protein which interacts with C4b binding protein (C4BP): l eptospiral c omplement regulator-acquiring p rotein A (LcpA). Here we show that LcpA also interacts with human factor H (FH), which remains functionally active once bound to the protein. Antibodies directed against short consensus repeat 20 (SCR20) inhibited binding of FH to LcpA by approximately 90%, thus confirming that this particular domain is involved in the interaction. We have also shown for the first time that leptospires bind human vitronectin and that the interaction is mediated by LcpA. Coincubation with heparin blocked LcpA-vitronectin interaction in a dose-dependent manner, strongly suggesting that binding may occur through the heparin binding domains of vitronectin. LcpA also bound to the terminal pathway component C9 and inhibited Zn 2+ -induced polymerization and membrane attack complex (MAC) formation. Competitive binding assays indicated that LcpA interacts with C4BP, FH, and vitronectin through distinct sites. Taken together, our findings indicate that LcpA may play a role in leptospiral immune evasion.

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