Primate Monocytes - CD14, CD16 - Ziegler-Heitbrock

IDENTIFICATION OF A NOVEL LIPOPOLYSACCHARIDE CORE BIOSYNTHESIS GENE CLUSTER IN BORDETELLA PERTUSSIS: INFLUENCE OF CORE STRUCTURE AND LIPID A GLUCOSAMINE SUBSTITUTION ON ENDOTOXIC ACTIVITY.

Abstract

Lipopolysaccharide (LPS), also known as endotoxin, is one of the main constituents of the Gram-negative bacterial outer membrane. Whereas its lipid A part is generally seen as the main determinant for endotoxic activity, the oligosaccharide moiety plays an important role in immune evasion and the interaction with professional antigen-presenting cells. Here, we describe a novel four-gene cluster involved in the biosynthesis of the Bordetella pertussis core oligosaccharide. By insertionally inactivating the genes and studying the resulting LPS structures, we show that at least two of the genes encode active glycosyltransferases, while a third one encodes a deacetylase also required for full-length oligosaccharide biosynthesis. In addition, we demonstrate that mutations in the locus differentially affect LPS and whole cell endotoxic activity. Furthermore, while analysing the mutant LPS structures, we confirmed a novel modification of the lipid A phosphate with glucosamine, and found that inactivation of the responsible glycosyltransferase reduces the endotoxic activity of the LPS.