Characteristics of lipopolysaccharide interaction with human peripheral-blood monocytes.
The interaction between radioiodinated lipopolysaccharide from Escherichia coli 0111:B4 (125I-LPS) and human peripheral-blood monocytes was studied. The association of 125I-LPS with monocytes at 37 degrees C appeared to depend on binding to the cell membrane with subsequent internalization of the molecule, and was not saturable with time (up to 2 h) or 125I-LPS concentration (up to 10 micrograms/ml). There was no apparent difference in the behaviour of unlabelled LPS and 125I-LPS with respect to monocyte association. 125I-LPS association with monocytes was inhibited by LPS and O-polysaccharide from E. coli 0111:B4 and Salmonella typhi 0901, but not by lipid A or polymyxin B. We propose that the mechanism of human monocyte stimulation by LPS involves polysaccharide-dependent binding to the cell membrane followed by internalization of the LPS molecule. We were unable to demonstrate a specific LPS receptor such as that found on murine B-lymphocytes.
D004591:Electrophoresis, Polyacrylamide Gel; D004705:Endocytosis; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D008070:Lipopolysaccharides / Q000378:metabolism* / Q000494:pharmacology; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D011112:Polymyxin B / Q000494:pharmacology; D013997:Time Factors
D008070:Lipopolysaccharides; D011112:Polymyxin B