ClearColi® BL21(DE3) cells are the first commercially available competent cells with a modified LPS that does not trigger the endotoxic response in mammalian cells. ClearColi™ cells lack outer membrane agonists for hTLR4/MD-2 activation; therefore, activation of hTLR4/MD-2 signalling by ClearColi is several orders of magnitude lower compared with E. coli wild-type cells, and heterologous proteins prepared from ClearColi are virtually free of endotoxic activity. After minimal purification from ClearColi cells, proteins or plasmids, which may still contain Lipid IVA, can still be used in most applications without eliciting an endotoxic response.