TY - JOUR
T1 - Lipoteichoic acid (LTA) from Staphylococcus aureus stimulates human neutrophil cytokine release by a CD14-dependent, Toll-like-receptor-independent mechanism
T2 - Autocrine role of tumor necrosis factor-α in mediating LTA-induced interleukin-8 generation
AU - Hattar, Katja
AU - Grandel, Ulrich
AU - Moeller, Alexander
AU - Fink, Ludger
AU - Iglhaut, Julia
AU - Hartung, Thomas
AU - Morath, Siegfried
AU - Seeger, Werner
AU - Grimminger, Friedrich
AU - Sibelius, Ulf
PY - 2006/3
Y1 - 2006/3
N2 - Objective: In sepsis, Gram-positive and Gram-negative bacteria provoke similar inflammatory processes. Whereas lipopolysaccharides (LPSs) are acknowledged as the principal immunostimulatory components of Gram-negative bacteria, the effect of the Gram-positive cell wall component lipoteichoic acid (LTA) is less well characterized. In the present study, we investigated the effect of highly purified LTA from Staphylococcus aureus on cytokine generation by isolated human neutrophils. Subjects: Isolated human neutrophils from healthy volunteers. Interventions: Incubation of neutrophils with purified LTA from S. aureus in the absence or presence of interleukin (IL)-10, anti-CD14, or anti-Toll-like-receptor antibodies. Measurements: Measurement of tumor necrosis factor (TNF)-α, IL-1β, and IL-8 by enzyme-linked immunosorbent assay. Analysis of IL-8 mRNA by reverse transcriptase polymerase chain reaction. Conclusions: The LTA challenge provoked a dramatic release of cytokines, with an early appearance of TNF-α and IL-1β and a delayed liberation of IL-8. The first phase of IL-8 production was induced directly by LTA, whereas the second phase was endogenously mediated by TNF-α, as it was largely abrogated by neutralizing anti-TNF-α antibodies. In contrast, IL1-β was not involved in LTA-induced IL-8 generation. Interestingly, the late phase of IL-8 generation could also be attenuated by exogenous IL-10, probably as a consequence of its downregulatory effects on TNF-α generation. When investigating the mechanism of LTA-induced cellular activation, activity-neutralizing antibodies demonstrated that CD14 was involved in LTA-mediated neutrophil cytokine generation. Using antibodies that neutralize the activity of Toll-like receptor 2 (TLR2) or 4 (TLR4), we also show that CD14-dependent, LTA-induced neutrophil activation did not proceed via TLR2- or TLR4-mediated pathways. In conclusion, LTA is a potent activator of human neutrophil cytokine generation, with the synthesis of the chemokine IL-8 being largely dependent on TNF-α generation in an autocrine fashion. This LTA-induced effect was inhibited by IL-10, dependent on CD14, and independent of TLR 2 or 4.
AB - Objective: In sepsis, Gram-positive and Gram-negative bacteria provoke similar inflammatory processes. Whereas lipopolysaccharides (LPSs) are acknowledged as the principal immunostimulatory components of Gram-negative bacteria, the effect of the Gram-positive cell wall component lipoteichoic acid (LTA) is less well characterized. In the present study, we investigated the effect of highly purified LTA from Staphylococcus aureus on cytokine generation by isolated human neutrophils. Subjects: Isolated human neutrophils from healthy volunteers. Interventions: Incubation of neutrophils with purified LTA from S. aureus in the absence or presence of interleukin (IL)-10, anti-CD14, or anti-Toll-like-receptor antibodies. Measurements: Measurement of tumor necrosis factor (TNF)-α, IL-1β, and IL-8 by enzyme-linked immunosorbent assay. Analysis of IL-8 mRNA by reverse transcriptase polymerase chain reaction. Conclusions: The LTA challenge provoked a dramatic release of cytokines, with an early appearance of TNF-α and IL-1β and a delayed liberation of IL-8. The first phase of IL-8 production was induced directly by LTA, whereas the second phase was endogenously mediated by TNF-α, as it was largely abrogated by neutralizing anti-TNF-α antibodies. In contrast, IL1-β was not involved in LTA-induced IL-8 generation. Interestingly, the late phase of IL-8 generation could also be attenuated by exogenous IL-10, probably as a consequence of its downregulatory effects on TNF-α generation. When investigating the mechanism of LTA-induced cellular activation, activity-neutralizing antibodies demonstrated that CD14 was involved in LTA-mediated neutrophil cytokine generation. Using antibodies that neutralize the activity of Toll-like receptor 2 (TLR2) or 4 (TLR4), we also show that CD14-dependent, LTA-induced neutrophil activation did not proceed via TLR2- or TLR4-mediated pathways. In conclusion, LTA is a potent activator of human neutrophil cytokine generation, with the synthesis of the chemokine IL-8 being largely dependent on TNF-α generation in an autocrine fashion. This LTA-induced effect was inhibited by IL-10, dependent on CD14, and independent of TLR 2 or 4.
KW - CD14 antigen
KW - Cytokines
KW - Interleukin-10
KW - Lipoteichoic acid
KW - Neutrophils
KW - Sepsis
KW - Toll-like receptors
UR - http://www.scopus.com/inward/record.url?scp=33644592813&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33644592813&partnerID=8YFLogxK
U2 - 10.1097/01.CCM.0000202204.01230.44
DO - 10.1097/01.CCM.0000202204.01230.44
M3 - Article
C2 - 16521278
AN - SCOPUS:33644592813
VL - 34
SP - 835
EP - 841
JO - Critical Care Medicine
JF - Critical Care Medicine
SN - 0090-3493
IS - 3
ER -