To elucidate the cellular activation mechanisms of lipoteichoic acid (LTA) compared with those of lipopolysaccharide (LPS), a quantitatively major LTA fraction, QM-1M, was prepared from hot phenol-water extracts of Enterococcus hirae (ATCC 9790) by hydrophobic octyl-Sepharose chromatography and by ion-exchange membrane (QMA-Mem Sep 1010) chromatography as a 60% 1-propanol- and 1 M NaCl-eluted fraction. Unlike the reference Escherichia coli LPS, QM-1M did not demonstrate any ability to induce cytokines in a human whole blood culture system in this study, whereas QM-1M induced a few cytokines such as interleukin (IL)-8 and tumor necrosis factor-alpha in human monocytic THP-1 cell and human peripheral mononuclear cell (PBMC) cultures in the absence of serum. Fetal calf and human sera decreased the above cytokine induction by QM-1M in THP-1 and PBMC cultures, whereas sera increased activities of the reference LPS. IL-8 induction in the absence of serum in response to QM-1M was demonstrated to proceed through a CD14-independent pathway unlike the reference LPS.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.