Lipopolysaccharides from Different Burkholderia Species with Different Lipid A Structures Induce Toll-Like Receptor 4 Activation and React with Melioidosis Patient Sera

• Published in: Infection and immunity Vol. 87; no. 12
• Main Authors: Sengyee, Sineenart, Yoon, Sung Hwan, West, T Eoin, Ernst, Robert K, Chantratita, Narisara
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01-12-2019
• Subjects: Amino Sugars - chemistry; Antibodies, Bacterial - immunology; Burkholderia - immunology; Burkholderia mallei - immunology; Burkholderia pseudomallei - immunology; Cross Reactions - immunology; Host Response and Inflammation; Humans; Lipid A - chemistry; Lipid A - immunology; Melioidosis - immunology; Melioidosis - microbiology; Molecular Conformation; Polysaccharides, Bacterial - immunology; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Toll-Like Receptor 4 - metabolism; diagnostics; antibody; innate immunity; serology; LPS structure; melioidosis; Burkholderia; bacterial infection; lipopolysaccharide; O-polysaccharide; TLR4
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.00692-19

Lipopolysaccharides (LPSs) of Gram-negative bacteria comprise lipid A, core, and O-polysaccharide (OPS) components. Studies have demonstrated that LPSs isolated from the pathogenic species
and
and from less-pathogenic species, such as
, are potent immune stimulators. The LPS structure of
, the causative agent of melioidosis, is highly conserved in isolates from Thailand; however, the LPSs isolated from other, related species have not been characterized to enable understanding of their immune recognition and antigenicities. Here, we describe the structural and immunological characteristics of the LPSs isolated from eight
species and compare those for
to those for the other seven species. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), gas chromatography (GC), SDS-PAGE, Toll-like receptor 4 (TLR4) stimulation, and immunoblot analysis were performed on these
species. MALDI-TOF profiles demonstrated that
lipid A contains predominantly penta-acylated species modified with 4-amino-4-deoxy-arabinose residues at both terminal phosphate groups. The lipid A could be differentiated based on mass differences at
1,511, 1,642, 1,773, and 1,926 and on fatty acid composition. LPSs of all species induced TLR4-dependent NF-κB responses; however, while SDS-PAGE analysis showed similar LPS ladder patterns for
,
, and
, these patterns differed from those of other
species. Interestingly, immunoblot analysis demonstrated that melioidosis patient sera cross-reacted with OPSs of other
species. These findings can be used to better understand the characteristics of LPS in
species, and they have implications for serological diagnostics based on the detection of antibodies to OPS.