TLR-4 surface display on human monocytes is increased in septic patients.
BACKGROUND
Sepsis is a serious condition, most often occurring as a complication of bacterial infections. The Toll-like receptors (TLR)-2 and TLR-4 have been identified as key molecules in response to Gram-positive and Gram-negative bacteria. This study aimed to assess possible alterations of the surface display of TLR-2 and TLR-4 on monocytes and granulocytes derived from patients with sepsis in comparison with healthy controls. -


METHODS
We have utilized flow-cytometry to determine the presence of TLR-2 and TLR-4 on the cell surface at baseline and in response to LPS (40 ng/ml) in vitro. -


RESULTS
We found no significant differences of TLR-2 display on monocytes and granulocytes from septic patients compared to controls. Surface display of TLR-4 on monocytes from septic patients at baseline was significantly higher than in healthy controls but there was no further response to LPS, whereas controls showed a significant increase of TLR-4 display on the cell surface after LPS stimulation. In contrast, TLR-4 baseline cell surface display on granulocytes was significantly lower in septic patients than in controls and there was no response to LPS in both groups. -


CONCLUSIONS
Our data suggest a complex relationship between TLR-4 display and bacterial challenge in vivo and in vitro.
Brandl
K
K
Department of Internal Medicine I, University of Regensburg, Germany.
Glück
T
T
Huber
C
C
Salzberger
B
B
Falk
W
W
Hartmann
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002478:Cells, Cultured; D005260:Female; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D016905:Gram-Negative Bacterial Infections / Q000378:metabolism; D016908:Gram-Positive Bacterial Infections / Q000378:metabolism; D006098:Granulocytes / Q000378:metabolism*; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018805:Sepsis / Q000097:blood*; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors
D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors