Ficolin-2 Lectin Complement Pathway Mediates Capsule-Specific Innate Immunity Against Invasive Pneumococcal Disease.

ABSTRACT: Reports conflict regarding which lectin-microbial ligand interactions elicit a protective response from the lectin pathway (LP) of complement. Using fluorescent microscopy, we demonstrate the human lectin ficolin-2 binds to Streptococcus pneumoniae serotype 11A capsule polysaccharide dependent on the O-acetyltransferase gene wcjE. This triggers complement deposition and promotes opsonophagocytosis of encapsulated pneumococci. Even partial loss of ficolin-2 ligand expression through wcjE mutation abrogated bacterial killing. Ficolin-2 did not interact with any pneumococcal non-capsule structures, including teichoic acid. We describe multiple 11A clonal derivatives expressing varying degrees of wcjE-dependent epitopes co-isolated from single blood specimens, likel

SUBMITTER: Nahm MH 

PROVIDER: S-EPMC8996173 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature