A lipoteichoic acid fraction of Enterococcus hirae activates cultured human monocytic cells via a CD14-independent pathway to promote cytokine production, and the activity is inhibited by serum components.
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.
Arakaki
R
R
Department of Microbiology and Immunology, Kagoshima University Dental School, Japan.
Sugawara
S
S
Nakashima
H
H
Kotani
S
S
Takada
H
H
D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D016983:Enterococcus / Q000276:immunology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology; D018950:Lipopolysaccharide Receptors / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology* / Q000302:isolation & purification; D009000:Monocytes / Q000166:cytology / Q000276:immunology*; D013682:Teichoic Acids / Q000276:immunology* / Q000302:isolation & purification
D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D013682:Teichoic Acids; C009900:lipoteichoic acid