Lipopolysaccharide Heterogeneity: Innate Host Responses to Bacterial Modification of Lipid A Structure

• Published in: Journal of Dental Research Vol. 84; no. 7; pp. 584 - 595
• Main Authors: Dixon, D.R., Darveau, R.P.
• Format: Book Review Journal Article
• Language: English
• Published: United States SAGE Publications 01.07.2005; SAGE PUBLICATIONS, INC
• Subjects: Animals; Bacterial Outer Membrane Proteins - immunology; Dentistry; Gram-Negative Bacteria - chemistry; Gram-Negative Bacteria - immunology; Humans; Immunity, Innate - immunology; Lipid A - chemistry; Lipid A - immunology; Lipopolysaccharides - chemistry; Lipopolysaccharides - immunology; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - immunology; Molecular Conformation; Mouth - microbiology; Protein Isoforms - chemistry; Protein Isoforms - immunology; Receptors, Immunologic - immunology; lipopolysaccharide (LPS); CD14; TLR; innate immunity; lipid A
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/154405910508400702

The innate host response system is composed of various mechanisms designed to detect and facilitate host responses to microbial components, such as lipopolysaccharides (LPS). To enable this to occur, innate systems contain multiple pattern recognition receptors (i.e., LBP, CD14, and TLRs), which identify certain features within bacterial LPS that are foreign to the host, as well as essential and uniquely specific for bacteria. Innate host identification of unique bacterial components or patterns, therefore, relies on the inability of bacteria to alter these essential or critical components dramatically. Historically, LPS have been viewed as essential outer-membrane molecules containing both a highly variable outer region (O-segment) as well as a relatively conserved inner region (lipid A). However, over the last decade, new evidence has emerged, revealing that increased natural diversity or heterogeneity within specific components of LPS, such as lipid A—resulting in minor to moderate changes in lipid A structure—can produce dramatic host responses. Therefore, examples of natural lipid A heterogeneity, and the mechanisms that control it, represent a novel approach in which bacteria modulate host responses and may thereby confer specific advantages to certain bacterial species under changing environmental host conditions.