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Evasion of killing by human antibody and complement through multiple variations in the surface oligosaccharide of H aemophilus influenzae
Author(s) -
Clark Sarah E.,
Eichelberger Kara R.,
Weiser Jeffrey N.
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12214
Subject(s) - phase variation , biology , sialic acid , lipopolysaccharide , antibody , context (archaeology) , microbiology and biotechnology , biochemistry , immunology , gene , virulence , paleontology
Summary The lipopolysaccharide ( LPS ) of H . influenzae is highly variable. Much of the structural diversity is derived from phase variation, or high frequency on‐off switching, of molecules attached during LPS biosynthesis. In this study, we examined the dynamics of LPS phase variation following exposure to human serum as a source of antibody and complement in multiple H . influenzae isolates. We show that lic2A , lgtC and lex2A switch from phase‐off to phase‐on following serial passage in human serum. These genes, which control attachment of a galα1–4gal di‐galactoside structure ( lic2A and lgtC phase‐on) or an alternative glucose extension ( lex2A phase‐on) from the same hexose moiety, reduce binding of bactericidal antibody to conserved inner core LPS structures. The effects of the di‐galactoside and alternative glucose extension were also examined in the context of the additional LPS phase variable structures phosphorylcholine ( ChoP ) and sialic acid. We found that di‐galactoside, the alternative glucose extension, ChoP , and sialic acid each contribute independently to bacterial survival in the presence of human complement, and have an additive effect in combination. We propose that LPS phase variable extensions serve to shield conserved inner core structures from recognition by host immune components encountered during infection.