Rhizobium leguminosarum chaperonin 60.3, but not chaperonin 60.1, induces cytokine production by human monocytes: activity is dependent on interaction with cell surface CD14.
As part of a program of work to understand the interaction of bacterial chaperonins with human leukocytes, we have examined 2 of the 3 chaperonin 60 (Cpn 60) gene products of the nonpathogenic plant symbiotic bacterium, Rhizobium leguminosarum, for their capacity to induce the production of pro- and antiinflammatory cytokines by human cells. Recombinant R. leguminosarum Cpn 60.1 and 60.3 proteins were added to human monocytes at a range of concentrations, and cytokine production was measured by sandwich enzyme-linked immunosorbent assay. In spite of the fact that the 2 R. leguminosarum Cpn 60 proteins share 74.5% amino acid sequence identity, it was found that Cpn 60.3 induced the production of interleukin (IL)-1beta, tumor necrosis factor alpha, IL-6, IL-8, IL-10, and IL-12, but not IL-4, interferon gamma, or GM-CSF (granulocyte-macrophage colony-stimulating factor), whereas the Cpn 60.1 protein failed to demonstrate any cytokine-inducing activity. The use of neutralizing monoclonal antibodies showed that the cytokine-inducing activity of Cpn 60.3 was dependent on its interaction with CD14. This demonstrates that CD14 mediates not only lipopolysaccharide but also R. leguminosarum Cpn 60.3 cell signaling in human monocytes.
Lewthwaite
Jo
J
Cellular Microbiology Research Group, Eastman Dental Institute, University College London, UK.
George
Roger
R
Lund
Peter A
PA
Poole
Steve
S
Tormay
Peter
P
Sharp
Lindsay
L
Coates
Anthony R M
AR
Henderson
Brian
B
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000096:biosynthesis*; D004731:Endotoxins / Q000378:metabolism; D005408:Flagellin / Q000378:metabolism; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism* / Q000382:microbiology; D011112:Polymyxin B / Q000378:metabolism; D016961:Rhizobium leguminosarum / Q000378:metabolism*; D016415:Sequence Alignment
D001426:Bacterial Proteins; D018834:Chaperonin 60; D016207:Cytokines; D004731:Endotoxins; D018950:Lipopolysaccharide Receptors; D005408:Flagellin; D011112:Polymyxin B