Low invasiveness of pneumococcal serotype 11A is linked to ficolin-2 recognition of O-acetylated capsule epitopes and lectin complement pathway activation.
J Infect Dis
; 210(7): 1155-65, 2014 Oct 01.
Article
em En
| MEDLINE
| ID: mdl-24683196
ABSTRACT
BACKGROUND:
The divergent epidemiological behavior of Streptococcus pneumoniae serotypes suggests that serotype-specific features such as capsule O-acetylation influence the propensity of a strain to cause invasive pneumococcal disease (IPD). We hypothesize that innate host factors mediate the observed negative association between IPD and the serotype 11A (ST11A) capsule O-acetyltransferase gene, wcjE.METHODS:
We evaluated the ability of ficolin-2, an initiator of the lectin complement pathway that was previously shown to bind ST11A pneumococci, to recognize and mediate complement-dependent opsonophagocytosis of different pneumococcal serotypes. We supplemented findings with an epidemiological meta-analysis comparing invasiveness of the 30 most prevalent pneumococcal serotypes.RESULTS:
Ficolin-2 bound ST11A capsule polysaccharide and other wcjE-containing pneumococcal serotypes, except ST9V and ST20B. Ficolin-2 did not bind wcjE-null serotypes, including the wcjE-null variant of ST11A, ST11E. We observed C1q-independent complement deposition and phagocytic killing of pneumococci expressing ST11A but not those expressing ST11E. Inhibition of ficolin-2 binding abrogated ST11A-associated complement deposition and phagocytosis. In children, invasiveness of ST11A was the lowest among serotypes tested in our meta-analysis, while ST9V was among the highest.CONCLUSIONS:
Ficolin-2 mediates serum protection by recognizing specific O-acetylated epitopes of pneumococcal capsule polysaccharides, exemplifying a novel host-microbe interaction that innately offers serotype-specific immunity to IPD.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Streptococcus pneumoniae
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Cápsulas Bacterianas
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Lectina de Ligação a Manose da Via do Complemento
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Lectinas
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Epitopos
Tipo de estudo:
Systematic_reviews
Limite:
Adolescent
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Adult
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Child
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Child, preschool
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Humans
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Infant
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Newborn
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article