Nontypeable haemophilus influenzae P5 binds human C4b-binding protein, promoting serum resistance

Oskar Thofte, Serena Bettoni, Yu Ching Su, John Thegerström, Sandra Jonsson, Emma Mattsson, Linda Sandblad, Sara Martı, Junkal Garmendia, Anna M. Blom, Kristian Riesbeck

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskriftPeer review

Sammanfattning

Nontypeable Haemophilus influenzae (NTHi) is a Gram-negative human pathogen that causes infections mainly in the upper and lower respiratory tract. The bacterium is associated with bronchitis and exacerbations in patients suffering from chronic obstructive pulmonary disease and frequently causes acute otitis media in preschool children. We have previously demonstrated that the binding of C4b binding protein (C4BP) is important for NTHi complement evasion. In this study, we identified outer membrane protein 5 (P5) of NTHi as a novel ligand of C4BP. Importantly, we observed significantly lower C4BP binding and decreased serum resistance in P5-deficient NTHi mutants. Surface expression of recombinant P5 on Escherichia coli conferred C4BP binding and consequently increased serum resistance. Moreover, P5 expression was positively correlated with C4BP binding in a series of clinical isolates. We revealed higher levels of P5 surface expression and consequently more C4BP binding in isolates from the lower respiratory tract of chronic obstructive pulmonary disease patients and tonsil specimens compared with isolates from the upper respiratory tract and the bloodstream (invasive strains). Our results highlight P5 as an important protein for protecting NTHi against complement-mediated killing.

Originalspråkengelska
Sidor (från-till)1566-1577
Antal sidor12
TidskriftJournal of Immunology
Volym207
Utgåva6
DOI
StatusPublished - 2021 sep. 15

Ämnesklassifikation (UKÄ)

  • Immunologi inom det medicinska området

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