LPS-RS

LPS from R. sphaeroides

Lipopolysaccharide from the photosynthetic bacterium Rhodobacter sphaeroides (LPS-RS) is a potent antagonist of lipopolysaccharide (LPS) from pathogenic bacteria [1]. Complete competitive inhibition of LPS activity is possible at a 100-fold excess of the antagonist. LPS-RS does not induce TLR4 signaling but is detected by the LAL assay, the standard endotoxin detection assay.

InvivoGen provides LPS-RS with two grades of purity:

• LPS-RS is a standard lipopolysaccharide (LPS) preparation extracted by a phenol-water mixture. It inhibits TLR4 activity, however, as LPS-RS contains other bacterial components, such as lipoproteins, it activates TLR2.
• LPS-RS Ultrapure is extracted by successive enzymatic hydrolysis steps and purified by the previously described phenol-TEA-DOC extraction protocol [2]. This process removes contaminating lipoproteins, and therefore LPS-RS Ultrapure does not activate TLR2 while retaining the ability to inhibit TLR4 activity. 

Reference:

1. Coats SR. et al., 2005. MD-2 mediates the ability of tetra-acylated and penta-acylated lipopolysaccharides to antagonize Escherichia coli lipopolysaccharide at the TLR4 signaling complex. J Immunol.;175(7):4490-8.
2. Hirschfeld M. et al., 2000. Cutting edge: repurification of lipopolysaccharide eliminates signaling through both human and murine toll-like receptor 2. J Immunol. 165(2):618-22.

Specifications

Specificity: TLR4 antagonist
LPS-RS standard is also a TLR2 agonist

Working concentration: 10 ng - 10 μg/ml

Endotoxin level: 1  x 10⁶ EU/mg

Solubility: 5 mg/ml in water

InvivoGen provides LPS-RS with two grades of purity: Standard and Ultrapure

Contents

LPS-RS:

• 5 mg lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS)
• 1.5 ml endotoxin-free water

LPS-RS Ultrapure:

• 1 mg lipopolysaccharide from Rhodobacter sphaeroides  Ultrapure (LPS-RS Ultrapure)
• 1.5 ml endotoxin-free water

LPS-RS is shipped at room temperature

Upon receipt it should be stored at -20 ̊C.
Upon resuspension, prepare aliquots of LPS-RS and store at 4°C for short term storage or -20 ̊C for long term storage.

Lyophilized product is stable 1 year at -20°C when properly stored.
Resuspended product is stable 1 month at 4°C and 6 months at -20°C.

Avoid repeated freeze-thaw cycles.

Description

LPS from the photosynthetic bacterium Rhodobacter sphaeroides (LPS-RS) is the first potent antagonist of toxic LPS in both human and murine cells and also prevents LPS-induced shock in mice [1].

LPS-RS is penta-acylated and as other under-acylated LPS seems to utilize at least two distinct mechanisms to block LPS-dependent activation of TLR4.

The main mechanism consists of direct competition between under-acylated LPS and hexa-acylated LPS for the same binding site on MD-2, while the secondary mechanism involves the ability of under-acylated LPS:MD-2 complexes to inhibit hexa-acylated endotoxin: MD-2 complexes function at TLR4 [2-5].

Complete competitive inhibition of LPS activity is possible at a 100 fold excess of the antagonist. LPS-RS does not induce TLR4 signaling but is detected by the LAL assay, the standard endotoxin detection assay. 

LPS-RS preparations (cat. code tlrl-rslps) contain lipopeptide contaminants, and therefore stimulate Toll-like receptor 2 (TLR2).

1. Qureshi, N. et al., 1999. Nontoxic RsDPLA as a potent antagonist of toxic lipopolysaccharide. p. 687-698. In: H. Brade, and S. M. Opal, and S. N. Vogel, and D. C. Morrison, eds. Endotoxin in Health and Disease 687. Marcel Dekker, New York.
2. Coats SR. et al., 2005. MD-2 mediates the ability of tetra-acylated and penta-acylated lipopolysaccharides to antagonize Escherichia coli lipopolysaccharide at the TLR4 signaling complex.J Immunol.;175(7):4490-8.
3. Teghanemt A. et al., 2005. Molecular basis of reduced potency of underacylated endotoxins. J Immunol. 175(7):4669-76.
4. Visintin A. et al., 2005. Pharmacological inhibition of endotoxin responses is achieved by targeting the TLR4 coreceptor, MD-2. J Immunol. 175(10):6465-72.
5. Saitoh S. et al., 2004. Lipid A antagonist, lipid IVa, is distinct from lipid A in interaction with Toll-like receptor 4 (TLR4)-MD-2 and ligand-induced TLR4 oligomerization. Int Immunol. 16(7):961-9.