British Journal of Rheumatology 1997;36:744–747 GELATINASE B IN CHRONIC SYNOVITIS: IMMUNOLOCALIZATION WITH A MONOCLONAL ANTIBODY B. GRILLET, J. DEQUEKER, L. PAEMEN,* B. VAN DAMME† and G. OPDENAKKER* Department of Rheumatology, *Laboratory of Molecular Immunology at the Rega Institute of Medical Research and †Department of Pathology, University of Leuven, Belgium SUMMARY Gelatinase B is a matrix metalloproteinase (MMP-9) involved in the remodelling of extracellular matrices of connective tissues. With the use of specific monoclonal antibodies against human gelatinase B, the producer cell types were pinpointed in histopathological sections of a number of arthritic diseases. In cases of acute joint trauma, chondromatosis, villonodular synovitis and a cyst of a bursa, high numbers of strongly immunopositive neutrophils were observed in additon to weaker staining macrophages. Activated macrophages with giant cell morphology clearly stained with the gelatinase B-specific monoclonal antibody in the case of villonodular synovitis and in an epidermoid cyst. However, in the sections from patients with rheumatoid arthritis, no immunostaining was seen. In other cases of chronic synovitis, however, within the lymphocyte nodular aggregates a strong gelatinase B expression was observed in morphologically identified dendritic cells. In conclusion, gelatinase B production in joint disease seems to be predominantly by neutrophils and cell types of the macrophage/antigen-presenting cell lineage. K : Gelatinase B, Monoclonal antibodies, Immunolocalization. cytes. It is constitutively present in serum and body fluids including synovial fluid. Gelatinase B (MMP-9, mol. wt 292 kDa) is mainly produced by neutrophilic granulocytes, which release gelatinase B within minutes after stimulation with the neutrophilic chemokine interleukin-8 (IL-8) [7]. Gelatinase B is induced in monocytes by IL-1 and in many other cell types (e.g. fibroblasts, endothelial cells, keratinocytes) by various agonists. In terms of protein domain structure, gelatinase B is so far the most complex MMP. It is the terminal member of the cascade leading to matrix degradation and its activity in vitro is modulated at four levels: de novo gene transcription (e.g. by IL-1), secretion (e.g. by IL-8), activation (e.g. by stromelysin and gelatinase A) and specific inhibitors (e.g. tissue inhibitors of metalloproteinases). Elevated levels of gelatinase B have been demonstrated in the biological fluids of patients suffering from various inflammatory diseases, including RA. Gelatinase B titres vary considerably in synovial fluid and are correlated with other parameters of disease activity [8]. In view of the increased titres of IL-8 and neutrophil cell counts in synovial fluid of RA patients, and because IL-8 stimulates the rapid release of gelatinase B by neutrophils, the neutrophil granulocyte is probably the major source of synovial gelatinase B, although limited production by monocytes/macrophages is also conceivable. In the synovial membrane of patients with RA, neutrophil granulocytes are, however, very sparse. In contrast, mononuclear cells are believed to play an important role in RA synovial membrane [9]. In primary cultures of adherent rheumatoid synovial cells, gelatinase B production was restricted to macrophages [5]. In order to localize the sites of gelatinase production in chronic inflammation, we analysed tissue samples of patients with different chronic inflammatory disorders of the joints and the surrounding tissue. C joint inflammation is likely to induce permanent joint damage. Rheumatoid arthritis (RA), for instance, is a chronic inflammatory disorder, with systemic features and joint involvement, resulting in an erosive synovitis and joint destruction. Many other disorders are more or less characterized by joint lesions. Damage to bone, cartilage, tendons and ligaments is mediated largely by proteinases [1]. Enzymes involved in the breakdown of the matrix elements, allowing inflammatory cells to migrate into the site of inflammation, may induce long-term irreversible damage. Metalloproteinases play an important role in this scenario. They act outside the cell at neutral pH and are capable of degrading the molecules of the extracellular matrix [2]. Among these, collagenase (matrix metalloproteinase-1 or MMP-1) and its zymogen activators are rate limiting in collagen degradation [3]. Collagenase activity was previously detected in the synovial fluid of patients with RA, and synovial fibroblasts were recognized as the major source of collagenase [4]. Stromelysin (MMP-3) is another member of the family of metalloproteinases, its substrate being non-collagen proteins such as proteoglycans, fibronectin and laminin [2]. Stromelysin is present in the synovial fluid of patients with RA and has been detected both in the synovial membrane (especially in fibroblasts [5]) and in cartilage [6]. A third group within the family of MMPs is formed by the gelatinases. These enzymes degrade denatured collagen, gelatin and some other extracellular matrix components. Two proteins have been isolated: gelatinase A (MMP-2, mol. wt 272 kDa) is produced by monocytes, fibroblasts, endothelial cells and keratinoSubmitted 5 August 1996; revised version accepted 10 December 1996. Correspondence to: B. Grillet, U.Z. Pellenberg-Reumatologie, Weligerveld 1, B-3212 Pellenberg, Belgium. = 1997 British Society for Rheumatology 744 GRILLET ET AL.: GELATINASE B IN CHRONIC SYNOVITIS Immunohistochemistry was performed using a highly specific monoclonal antibody against gelatinase B [10]. MATERIALS AND METHODS Tissues Synovial tissue from a range of joint inflammations was obtained from biopsies and surgical interventions carried out for other medical reasons. Thirteen samples were analysed: 11 from the synovial membrane of the joint, two from cysts. The tissues were fixed in formaldehyde and routinely processed through paraffin. Monoclonal gelatinase B antibody and Western blot analysis Gelatinase B-specific monoclonal antibodies were developed recently [10]. One of these, REGA-2D9, is an IgG1 monoclonal with a dissociation constant of 2.9 × 10−9 towards pure human gelatinase. B. The corresponding hybridoma was grown in pristaneprimed mice, the ascites collected and purified on protein A columns, and used for immunohistochemical localization of gelatinase B. In Western blot analysis of reduced crude synovial fluid samples, the monoclonal REGA-2D9 reacted with only one protein band which was gelatinase B specific. Immunolocalization Studies were performed using standard immunohistochemical techniques. To inactivate endogenous peroxidase, the slides were pre-treated with 0.3% hydrogen peroxide in methanol. The samples were incubated for 30 min at room temperature with 50 ml aliquots of the REGA-2D9 monoclonal antibody. After three washes with phosphate-buffered saline (PBS), the slides were incubated with biotin-linked rabbit anti-mouse IgG1 (Dako) for 30 min. Finally, after three washes with PBS, the slides were incubated with peroxidase-labelled avidin–biotin complex (Dako) for 30 min. The peroxidase reaction was performed with 0.6 mg/ml 3-3'-diamino-azo-benzidine in 0.01% hydrogen peroxide in PBS. Control slides were treated in an identical manner, except that an irrelevant IgG1 mouse mAb was used in the first step. All sections were counterstained with haematoxylin. RESULTS Clinical picture Tissue samples were analysed from the 13 patients, who were aged between 14 and 65 yr (mean 45 yr); seven were males, six were females. They all suffered from a joint inflammation for more than 6 weeks. RA, in agreement with the criteria of the American College of Rheumatology (ACR) [11], was present in two patients. In two other patients, a chronic synovitis indicative for RA was present, albeit without satisfying the criteria for RA. One patient suffered from pes planus resulting in mechanical damage to the joint. In two other patients, the synovitis occurred after an acute mechanical insult to the joint. Osteochondromatosis was diagnosed in 745 two patients. A villonodular synovitis was seen in two others. In two patients the biopsy was from a cyst: an epidermoid cyst in one patient and a cyst of the bursa synovialis of the popliteal muscle in the other patient. Histopathology Considering the 11 samples of joint tissue, hyperplasia of the synovial lining was seen in five patients (two with RA, two with synovitis following an acute mechanical insult and one patient with chondromatosis). In eight cases, the inflammation was characterized by a lymphocytic infiltrate organized in nodular aggregates. In a patient with chondromatosis, granulocytes were abundantly present. In the cases of villonodular synovitis and in the cysts, the infiltrate contained predominantly macrophages, frequently accompanied by giant cells. Immunohistology Immunoreactive gelatinase B was present in seven of the 13 samples. Neutrophil granulocytes were abundantly present in the synovial tissue of one patient with chondromatosis (Fig. 1A). They were seen in three other samples as well. Staining of macrophages was seen in all seven positive specimens (Fig. 1B). These cells had the histological aspect of dendritic cells in two samples: one was from a patient with a chronic synovitis not fulfilling the ACR criteria of RA (Fig. 1C), the other was from a patient with chondromatosis. In the five other samples, the macrophages were the predominant positive cells of the inflammatory infiltrate (two samples of villonodular synovitis and two cysts). Giant cells were positive as well (Fig. 1D). Overall positivity of the mononuclear cells was significant, but weaker than that of neutrophil granulocytes. Control immunohistochemistry with an irrelevant mouse IgG1 was negative in all cases (Fig. 1F). CONCLUSION AND DISCUSSION Gelatinase B was localized by immunohistochemistry with a specific monoclonal antibody in the synovial tissue of patients with joint diseases. Neutrophil granulocytes are a major source of gelatinase B in the synovial fluid, but are rarely present in the synovial membrane. Neutrophils were present in three samples of synovial membrane and in one cyst. These neutrophils yielded the strongest immunoreactivity observed. This is in accordance with previous biochemical data: neutrophils contain gelatinase B granules which are promptly released under the influence of IL-8, whereas other cells, e.g. monocytes, synthesize de novo smaller amounts of gelatinase B when triggered by IL-1 [7, 8]. Cells of the monocyte/macrophage lineage stained for gelatinase B in 7/13 samples. As macrophages are dependent on cytokine stimulation to produce gelatin- 746 BRITISH JOURNAL OF RHEUMATOLOGY VOL. 36 NO. 7 F. 1.—Legend opposite. GRILLET ET AL.: GELATINASE B IN CHRONIC SYNOVITIS 747 F. 1.—Immunohistochemistry of gelatinase B in chronic synovial diseases. Gelatinase B was detected by means of a specific mouse monoclonal antibody in formalin sections of joint tissues. The second antibody was a biotin-linked rabbit anti-mouse IgG1. Staining was performed by peroxidase-labelled avidin–biotin complex. Immunopositivity is indicated by red–brown colouring. (A) Strong gelatinase B staining of granulocytes in a patient with chondromatosis (original magnification ×300). (B) Gelatinase B immunoreactivity of granulocytes and macrophages in a patient with a synovitis secondary to an acute trauma (original magnification ×640). (C) A lymphocytic nodular aggregate in a patient with a chronic synovitis. Immunohistochemical staining for gelatinase B in mononuclear cells with dendritic morphology (original magnification ×600). (D) Staining of gelatinase B in macrophages and giant cells of a patient with a villonodular synovitis (original magnification ×400). (E) Immunohistochemical staining for gelatinase B in mononuclear cells with dendritic morphology in a patient with chronic synovitis (original magnification ×400). (F) The same sample as in (E), using an irrelevant IgG1 mouse monoclonal antibody in the first step as a control, demonstrating the lack of staining (original magnification ×400). ase B [8], the present data are in agreement with the stimulated state of macrophages in the samples of synovitis tissue. On several occasions, macrophages organized into giant cells were seen in the samples of villonodular synovitis and in an epidermoid cyst. These giant cells stained well with the anti-gelatinase B monoclonal antibody. In a patient with a chronic synovitis with lymphocytic infiltration and in a patient with chondromatosis, morphologically identified dendritic cells embedded in aggregates of lymphocytes stained for gelatinase B. Besides their potential antigen-presenting role, macrophages are believed to play an important role in driving or regulating the chronic inflammatory process by the production of cytokines such as IL-1, tumour necrosis factor-a (TNF-a) and IL-6. In addition, monocytes are involved in the secretion of gelatinase B in vitro [3, 8]. Here we document the specific cellular production of gelatinase B molecules in disease states. Functionally, the gelatinase can be used by the macrophage in several ways: to clear the way for its own migration, but also in the proteolytic conversion of extracellular matrix components into remnant epitopes generating autoimmunity (REGA-model) [12]. In contrast to the other metalloproteinases collagenase and stromelysin that are produced by the synovial lining [4], especially the fibroblasts [5], gelatinase B is produced by the infiltrating cells of monocyte/macrophage lineage. Gelatinase may be responsible for the destruction of cartilage and bone, but the abundance of gelatinase B in synovial fluid compared to synovial tissue [8] emphasizes the role of synovial fluid as a potential source of gelatinase B in tissue damage. Further analysis will be needed to determine to what extent immunotyping with gelatinase B can be used as a marker for a particular disorder or for a more damaging joint disease. A The present study was supported by the ‘Geconcerteerde Onderzoeksacties’ of the Flemish Government, by the General Saving and Retirement Fund (ASLK), and by the National Fund for Scientific Research (NFWO). LP holds a fellowship from the Charcot Foundation, Belgium. The help of Erik Martens in monoclonal antibody production and purification is appreciated. R 1. Werb Z. Proteinases and matrix degradation. In Kelley WN, Harris ED Jr, Ruddy S, Sledge CB, eds. Textbook of rheumatology. Philadelphia: WB Saunders, 1989. 2. Woessner JF Jr. Matrix metalloproteinases and their inhibitors in connective tissue remodeling. FASEB J 1991;5:2145–54. 3. Opdenakker G, Van Damme J. Cytokines and proteases in invasive processes: molecular similarities between inflammation and cancer. Cytokine 1992;4:251–8. 4. McCachren SS. Expression of metalloproteinases and metalloproteinase inhibitor in human arthritis synovium. Arthritis Rheum 1991;34:1085–93. 5. Tetlow LC, Lees M, Ogata Y, Nagase H, Woolley DE. Differential expression of gelatinase B (MMP-9) and stromelysin-1 (MMP-3) by rheumatoid synovial cells in vitro and in vivo. Rheumatol Int 1993;13:53–9. 6. Wolfe GC, MacNaul KL, Buechel FF, MacDonnell J, Hoerrner LA, Lark MW et al. Differential in vivo expression of collagenase messenger RNA in synovium and cartilage. Arthritis Rheum 1993;36:1540–7. 7. Masure S, Proost P, Van Damme J, Opdenakker G. Purification and identification of 91-kDa neutrophil gelatinase. Release by activating peptide interleukin-8. Eur J Biochem 1991;198:391–8. 8. Opdenakker G, Masure S, Grillet B, Van Damme J. Cytokine-mediated regulation of human leukocyte gelatinases and role in arthritis. Lymphokine Cytokine Res 1991;10:317–24. 9. Firestein GS, Zvaifler NJ. How important are T cells in chronic rheumatoid synovitis? Arthritis Rheum 1990; 33:768–73. 10. Paemen L, Martens E, Masure S, Opdenakker G. Monoclonal antibodies specific for natural human neutrophil gelatinase B used for affinity purification, quantitation by two-site ELISA and inhibition of enzymatic activity. Eur J Biochem 1995;234:759–65. 11. Arnett FC, Edworthy SM, Bloch DA et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 1988;31:315–24. 12. Opdenakker G, Van Damme J. Extracellular proteases in autoimmune diseases. Immunol Today 1994;15:104–7.
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