Purchase List Labs endotoxin or Lipopolysaccharides (LPS) for research and clinical investigation. This material has been extracted from bacterial cell walls of E. coli O111:B4, O55:B5, O157:H7, J5 and K12; Salmonella typhimurium, Salmonella minnesota and Bordetella pertussis. Both E. coli endotoxin and Salmonella endotoxin have been further purified to remove traces of residual protein and nucleic acids, producing the Ultra Pure LPS.
- How did we make Ultra Pure Lipopolysaccharide? Recently, we have developed proprietary chromatography methods, effectively removing traces of protein and nucleic acid from lipopolysaccharides while maintaining a consistently high concentration of endotoxin units; this product is known as List HPTTM LPS and is produced from E. coli O113.
- What other kind of Lipopolysaccharide is available? Also available are both diphosphoryl and monophosphoryl Lipid A (MPLA) prepared from E. coli K12 D31m4 and Salmonella minnesota R595 (Re), respectively. Lipid A, a disaccharide with fatty acid side chains, recognized by TLR4 receptors, is the component responsible for the endotoxic activity of LPS. Removal of one phosphate group from Lipid A produces MPLA which has reduced toxicity while retaining the ability to stimulate the immune system. MPLA is used as an adjuvant in various vaccines. To purchase MPLA look for product #401 in the catalog of LPS. List Labs sells LPS made in the USA.
- What is the structure of Lipopolysaccharide? LPS structure may be generally described as three linked regions. The first structural feature is the lipid component Lipid A, primarily responsible for the effects of endotoxin. Linked to Lipid A is the core antigen or R polysaccharide, a short chain of sugars including 2-keto 3-deoxyoctonate (KDO). The third structural feature is attached to the core polysaccharide and is more elaborate, containing up to 40 repeating subunits of 3 to 5 sugars, referred to as the O antigen, O side chain or O polysaccharide. Variations in the composition of the O antigen account for the species specific antibody responses. Lipid A, acting alone or as a component of LPS, is a potent modulator of the mammalian immune response. The presence of Lipid A or LPS in mammalian macrophages or endothelial cells triggers a signaling cascade leading to the secretion of pro-inflammatory cytokines and nitric oxide. LPS also acts as a B cell mitogen. Differences in Lipid A fatty acid side chain structures may be responsible for variations of the known effects on the immune system.
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