A survey of Haemophilus influenzae strains indicated that around one-third of capsular strains and over two-thirds of non-typeable strains included sialic acid in their lipopolysaccharides (LPS). Mutation of the CMP-Neu5Ac synthetase gene (siaB) resulted in a sialylation-deЖcient phenotype. Isogenic pairs, wild type and siaB mutant of two non-typeable strains were used to demonstrate that sialic acid influences resistance to the killing effect of normal human serum but has little effect on attachment to, or invasion of, cultured human epithelial cells or neutrophils. We determine for the Жrst time the site of attachment of sialic acid in the LPS of a non-typeable strain and report that a small proportion of glycoforms include two sialic acid residues in a disaccharide unit.
Lipopolysaccharide, Haemophilus, Haemophilus influenzae, strain, structural, characterization, acid, sialic acid, resistance, serum, serum resistance, distribution, influence
NCBI PubMed ID: 10447878Journal NLM ID: 8712028Publisher: Blackwell Publishing
Correspondence: dhood@molbiol.ox.ac.uk
Institutions: Molecular Infectious Diseases Group, University of Oxford Department of Paediatrics, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK.
Methods: MS
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