LPS from E. coli EH100 (Ra) TLRpure Sterile Solution (500 ug), Adipogen Life Sciences. Chemical. Isolated and purified from E. coli strain EH100. Activation of cells by LPS is mediated by the Toll-like receptor 4 (TLR4). For optimal interaction with LPS, TLR4 requires association with myeloid differentiation protein 2 (MD-2). According to current consensus activation of TLR4 is preceded by the transfer of LPS to membrane-bound (m) or soluble (s) CD14 by LPS-binding protein (LBP). Re-form LPS and lipid A, but not S-form LPS, are capable of inducing TNF-alpha responses also in the absence of CD14. LPS, synthesized by most wild-type (WT) Gram-negative bacteria (S-form LPS), consists of three regions, the O-polysaccharide chain, which is made up of repeating oligosaccharide units, the core oligosaccharide and the lipid A, which harbors the endotoxic activity of the entire molecule.