Lipid A Monophosphoryl, Salmonella minnesota R595

Lipopolysaccharide (LPS) structures 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.

Source:
Lipid A Monophosphoryl from Salmonella minnesota R595

Analysis:
2-Keto-3-deoxyoctonate (KDO)- 0.027%
Phosphate- 3.4%

Activity:
The hydrolysis conditions employed here yield a preparation which, as assessed by thin layer chromatography and phosphate analysis, is primarily monophosphoryl lipid A (i.e., the glucosamine-1-phosphate group is no longer present and only the glucosamine-4'-phosphate remains). This product, therefore, would be expected to be mitogenic but considerably less toxic than its parent LPS or a diphosphoryl lipid A preparation that is prepared using milder hydrolysis conditions and in which the glucosamine-1-phosphate group is still present.

Reconstitution:
This product is provided as a lyophilized powder, sealed under vacuum. Lipid A is insoluble in water. It may be suspended in DMSO or 0.5% triethylamine. A usable suspension may also be achieved in water by heating at 50°C combined with intermittent vortexing and/or sonication. This product should be stored at 4°C prior to and following reconstitution.

Storage and Stability:
Lyophilized powder may be stored at 4°C. Reconstitute with sterile buffer. Aliquot to avoid repeated freezing and thawing. Store at 4°C. Reconstituted product is stable for 6 months at 4°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.