Inhibitors of interleukin 1 activity in synovial fluids and in cultured synovial fluid mononuclear cells.
Measurement of interleukin 1 (IL-1) in synovial fluids (SF) yielded variable results and implied the presence of an inhibitory activity. As peripheral blood monocytes produce an IL-1 receptor antagonist (IL-1ra), we investigated whether SF mononuclear cells (SFMC) also secreted such inhibitory activity. MC isolated from inflammatory SF produced, in addition to variable levels of IL-1, a specific IL-1 inhibitor of approximately 23 kDa which blocked both IL-1 biological activity and binding to its receptor. Western blot, using a polyclonal antibody to rhIL-1ra, indicated that SFMC secreted material that shared immunological crossreactivity with the cloned IL-1ra. IL-1 inhibitory activity was also detected in SF but not formally demonstrated to be related to IL-1ra. In conclusion, SFMC could produce IL-1ra and an imbalance between IL-1 and its specific antagonist may be relevant to the severity of joint destruction.
Roux-Lombard
P
P
Division of Immunology and Allergy (Hans Wilsdorf Laboratory), University Hospital, Geneva, Switzerland.
Modoux
C
C
Vischer
T
T
Grassi
J
J
Dayer
J M
JM
D015153:Blotting, Western; D002469:Cell Separation; D002478:Cells, Cultured; D002850:Chromatography, Gel; D006801:Humans; D007124:Immunoenzyme Techniques; D007375:Interleukin-1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*; D011994:Recombinant Proteins; D013582:Synovial Fluid / Q000166:cytology / Q000378:metabolism*
D007375:Interleukin-1; D011994:Recombinant Proteins