Complement factor H binding by different Lyme disease and relapsing fever Borrelia in animals and human.
BACKGROUND
Borreliae employ multiple immune evasive strategies such as binding to complement regulatory proteins [factor H (fH) and factor H like-1 (FHL1)], differential regulation of surface membrane proteins, antigenic variation, and binding of plasminogen/plasmin and matrix metalloproteinases. As a complement regulatory subunit, fH serves as a cofactor for the factor I-mediated cleavage of C3b. fH binding by Borrelia has been correlated with pathogenesis as well as with host diversity. Here we show the differential binding of borrelial proteins to fH from human and animal sera.


RESULTS
Affinity ligand binding experiments, 2-D electrophoresis, and protein identification and peptide de novo sequencing based on mass spectrometry, revealed novel fH putative binding proteins of Lyme- and relapsing fever Borrelia. An OspA serotype-associated differential human and animal fH binding by B. garinii was also observed, which could be related with the ability of some strains from serotypes 4 and 7 to invade non-nervous system tissues. Also, the variable affinity of binding proteins expressed by different Borrelia to animal fH correlated with their host selectivity.


CONCLUSIONS
The novel animal and human putative fH binding proteins (FHBPs) in this study underscore the importance of evasion of complement in the pathogenesis of Borrelia infections.
Bhide
Mangesh R
MR
Laboratorio de Espiroquetas y Patógenos Especiales, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. mangeshbhide@hotmail.com
Escudero
Raquel
R
Camafeita
Emilio
E
Gil
Horacio
H
Jado
Isabel
I
Anda
Pedro
P