Lipopolysaccharides from Escherichia coli O55:B5

Lipopolysaccharides (LPS) are complex glycolipids that contain several components. Enterobacteriaceae, such as E. coli, have highly conserved lipid A linked to the antigenic O-polysaccharide. Hydrophobic lipid A forms the outer most component that plays a role in the biological properties attributed to endotoxic LPS. A short core oligosaccharide (core OS) is found to be attached to lipid A. Enterobacteria contain an antigenic, repeat-structure O-polysaccharide (O-PS) attached to the distal core OS to form smooth LPS. O-PS in E. coli contains ∼170 distinct antigens that interact with the host immune system. Based on the core OS structures in E. coli, they have been designated K-12 and R1 to R4.

LPS (lipopolysaccharide) from Escherichia coli 055:B5 has been used:

• to stimulate human PBMC to secrete cytokine.
• to stimulate wild type embryonic fibroblasts and mutants for the induction of phosphorylation of p56
• in the measurement of tumor necrosis factor-α levels and nuclear factor-κB p65 activities after stimulation
• in the stimulation of hamster lymphocytes in vitro
• to induce activated dendritic morphology in murine macrophage cell line in a study

Lipopolysaccharides (LPSs) are characteristic components of the cell wall of Gram-negative bacteria. LPS and its lipid A moiety stimulate cells of the innate immune system by the Toll-like receptor 4 (TLR4), a member of the Toll-like receptor protein family, which recognizes common pathogen-associated molecular-patterns (PAMPs).

LPS (lipopolysaccharide) is a major constituent of the outer membrane of most gram negative bacteria. It is a highly immunogenic antigen with the ability to enhance immune responses to soluble antigens. The LPS confers antigenic and endotoxic characters to the bacteria. They are also important in resistance to infection by phages.

Lipopolysaccharides are supplied as lyophilized, γ-irradiated powders. To reconstitute, add 1 ml sterile balanced salt solution or tissue culture medium to the vial (1 mg) and gently swirl until the powder dissolves. Reconstituted product may be further diluted to desired working concentrations using sterile balanced salt solution or tissue culture medium.