DOI: 10.1101/479022Nov 26, 2018Paper

Decoration of the enterococcal polysaccharide antigen EPA is essential for virulence, cell surface charge and sensitivity to effector molecules of innate immunity

BioRxiv : the Preprint Server for Biology
Robert E SmithStéphane Mesnage

Abstract

Enterococcus faecalis is an opportunistic pathogen with an intrinsically high resistance to lysozyme, a key effector of the innate immune system. This high level of resistance requires several genes (oatA, pgdA, dltA and sigV) acting synergistically to inhibit both the enzymatic and cationic antimicrobial peptide activities of lysozyme. We sought to identify novel genes modulating E. faecalis resistance to lysozyme. Random transposon mutagenesis carried out in the quadruple oatA/pgdA/dltA/sigV mutant led to the identification of several independent insertions clustered on the chromosome. These mutations were located in a locus referred to as the enterococcal polysaccharide antigen (EPA) variable region located downstream of the highly conserved epaA-epaR genes proposed to encode a core synthetic machinery. The epa variable region was previously proposed to be responsible for EPA decorations, but the role of this locus remains largely unknown. Here, we show that EPA decoration contributes to resistance towards charged antimicrobials and underpins virulence in the zebrafish model of infection by conferring resistance to phagocytosis. Collectively, our results indicate that the production of the EPA rhamnopolysaccharide backbone i...Continue Reading

Related Concepts

Eicosapentaenoic Acid
Antigens
Chromosomes
Genes
Phagocytosis
Polymers
Enterococcus faecalis
Virulence
Zebrafish
Antimicrobial Cationic Peptides

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