title: In vitro activation of human chondrocytes and synoviocytes by a human interleukin-1-like factor.
abstract: Monocytes have been shown to secrete factors which stimulate the destruction of cartilage. Since one of the monocyte products, interleukin-1 (IL-1), has been shown to stimulate the release of collagenase and prostaglandin E from synoviocytes, we have investigated whether IL-1 is also responsible for chondrocyte activation. Purified preparations of IL-1 derived from human blood monocytes stimulated the production of prostaglandin E and plasminogen activator by human articular chondrocytes. After Sephadex G-75 chromatography, the lymphocyte-activating and the chondrocyte-activating activities of IL-1 eluted together in the regions corresponding to the void volume and to Kav = 0.2-0.3 (Mr 30,000-45,000) and Kav = 0.5-0.65 (Mr 12,000-17,000). The major peak of stimulating activity was the 12,000-17,000 dalton peak. Upon further analysis of the 12,000-17,000 dalton peak by isoelectric focusing, the major peak of lymphocyte-activating factor activity was recovered at a pI of 6.3 with a minor peak at 4.6-5.3. Similar patterns of activity were observed when the fractions were assayed for the stimulation of the production of prostaglandin E and plasminogen activator by human chondrocytes and of prostaglandin E by human synoviocytes. Treatment of the partially purified lymphocyte activating factor with phenylglyoxal reduced the thymocyte-stimulating activity 99% and the chondrocyte-stimulating activity 100%. These results suggest that IL-1 may stimulate the degradation of connective tissues during inflammation.
mesh_terms: D002358:Cartilage, Articular / Q000166:cytology*; D002478:Cells, Cultured; D002850:Chromatography, Gel; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007525:Isoelectric Focusing; D010960:Plasminogen Activators / Q000096:biosynthesis; D011458:Prostaglandins E / Q000096:biosynthesis; D013583:Synovial Membrane / Q000166:cytology*
chemical_list: D007375:Interleukin-1; D011458:Prostaglandins E; D010960:Plasminogen Activators