2015 Volume 64 Issue 1 Pages 14-21
It has been revealed that lipopolysaccharide, which is a component of the cell walls of Gram-negative bacteria, induces monocytes and vascular endothelium cells to produce interleukin-6 (IL-6) and tissue factor (TF), and its relevance to the development of disseminated intravascular coagulation (DIC) its symptoms has attracted attention. We investigated the relationship between the positivity rates for TF/IL-6 and bacterial strain in DIC sepsis. In this study, we used Gram-negative bacteria, Gram-positive bacteria and yeast as stimulants. Moreover, we stimulated cells with both bacterial cells and their extracts. We prepared cells of the human monocyte cell line U937 and peripheral blood mononuclear cells (PBMCs), stimulated them with stimulant LPS, various clinical bacteria [Escherichia coli (E. coli), Staphylococcus aureus, coagulase-negative Staphylococci (CNS), Klebsiella pneumoniae, Candida albicans] and their extracts. As detection procedures, we immunostained U937 cells or PBMCs with an FITC-labeled anti-human TF antibody and a PE-labeled anti-IL-6 antibody, and measured by flow cytometry the extracellular and intracellular products of TF and IL-6 before and after the addition of the stimulant. There were significant differences in positivity rates among bacterial species, whereas no significant differences were observed among bacteria strains. Furthermore, there were no significant differences in positivity rates between bacterial bodies and their extracts. In U937 cells, E. coli induced the highest positivity rate for TF, and CNS induced the highest positivity rate for IL-6. In PBMCs, there were individual differences in positivity rates for TF and IL-6. As to the reactivity of a living body with sepsis, we suggest that differences in individual specificities and sensitivities of living bodies are larger than those in bacterial species and strains.