[Show abstract][Hide abstract] ABSTRACT: Peptide 263-275 is the immunodominant epitope of human cartilage (HC) gp-39, a candidate autoantigen in rheumatoid arthritis (RA). We recently generated and characterized a monoclonal antibody (mAb) called 12A, which is directed against HLA-DR4/HC gp-39(263-275) complexes and inhibits specific T cell responses in vitro. The aim of the present study was to analyze whether presentation of the immunodominant epitope of HC gp-39 by shared epitope-positive synovial dendritic cells is a specific event in the development of chronic synovial inflammation in RA.
Staining with mAb 12A was performed on synovium obtained from clinically swollen joints in 65 patients with RA and 67 non-RA controls and from joints without clinical effusion in 9 additional patients with RA.
Monoclonal antibody 12A staining was observed in the synovium of 40 of the 65 patients with RA. Histologically, expression of HC gp-39, lymphoid aggregates, CD3, and CD1a as well as the global inflammation score were higher in mAb 12A-positive RA synovium than in mAb 12A-negative synovium, indicating a follicular synovitis in these samples. Accordingly, mAb 12A stained dendritic cells in the close vicinity of lymphoid aggregates. No mAb 12A staining was detected in synovium obtained from RA joints without effusion. Clinically, there were no correlations between mAb 12A staining and clinical or biologic parameters in RA. However, positive staining was observed in 61.5% of the inflamed RA synovial samples compared with only 3.0% of the control samples (P < 0.001). This mAb 12A staining was not related to intracellular citrullinated peptides, which are another specific histologic marker for RA.
Presentation by synovial dendritic cells of the immunodominant epitope of HC gp-39, in the context of the shared epitope, is associated with characteristic histologic features of follicular synovitis and is highly specific for RA. This suggests a contribution to the autoimmune-related tissue inflammation and provides a new and independent tool for the immunopathologic diagnosis of RA.
[Show abstract][Hide abstract] ABSTRACT: Recently human cartilage gp-39 (HC gp-39) was identified as a candidate autoantigen in rheumatoid arthritis (RA). To further investigate the relevance of this Ag in RA, we have generated a set of five mAbs to a combination epitope of complexes of HC gp-39(263-275) and the RA-associated DR alpha beta 1*0401 HLA class II molecules. FACS studies revealed that these mAb recognize specific complexes on homozygous DR alpha beta 1*0401-positive B lymphoblastoid cells pulsed with HC gp-39(263-275). The best mAb, 12A, was further characterized using a set of irrelevant DR alpha beta 1*0401-binding peptides and truncated/elongated versions of HC gp-39(263-275) itself. The minimal epitope recognized in combination with DR alpha beta 1*0401 was HC gp-39(263-273). Peptides not encompassing HC gp-39(263-273) were not recognized. Three of five mAb were able to inhibit (up to 90%) the response of HC gp-39(263-275)-specific DR alpha beta 1*0401-restricted T cell hybridomas to peptide-pulsed APC or purified complexes. Using mAb 12A, we have been able to identify and localize dendritic cells that present DR alpha beta 1*0401/HC gp-39(263-275) complexes in synovial tissue of DR alpha beta 1*0401-positive RA patients, indicating local presentation of the HC gp-39(263-275) epitope in the inflamed target tissue by professional APC. These data support a role of HC gp-39 in the local autoimmune response that leads to chronic inflammation and joint destruction.
The Journal of Immunology 07/2003; 170(11):5719-27. DOI:10.4049/jimmunol.170.11.5719 · 4.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Adjuvant Arthritis (AA) can be induced by passive transfer of a T cell clone (A2b) derived from arthritic rats, specific for Heat Shock Protein 60, HSP60 176-190. Furthermore, a crucial role for T cells with HSP60 176-190 specificity in AA was shown by induction of tolerance using HSP60 176-190 or by immunization with an altered peptide ligand based on the same sequence. To study clonal expansion of A2b-like T cells during AA and to determine their role in AA induction, we generated a clonotypic antibody, 16C4, specific for the TCR of the A2b T cell clone (TCR AV11S1/BV18). This antibody stained A2b T cells in flow cytometry experiments, induced proliferation of A2b cells when fixed on a solid support, and inhibited antigen-induced A2b proliferation when added in solution. A2b-like T cells were detected in a low frequency in lymphoid organs of arthritic rats. Thus, as in vivo administration of 16C4 did not inhibit AA, cells containing the determinant recognized by 16C4 are possibly not the sole contributors to AA development. Furthermore, epitope specific interventions by antigen administration may be possible even in cases where the epitope specific T cell clonotype is of low frequency.
Journal of Autoimmunity 09/2000; 15(1):1-8. DOI:10.1006/jaut.2000.0384 · 8.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To evaluate plasma human cartilage glycoprotein (HC gp-39) as a possible marker for the presence and/or activity of rheumatoid arthritis (RA) and other inflammatory conditions.
HC gp-39 is a secretory product of chondrocytes, synovial cells, macrophages, and neutrophils. HC gp-39, also described as YKL-40, was found to be a marker of joint disease and tissue injury in RA and various other diseases.
Levels of HC gp-39 were determined by a sandwich enzyme linked immunosorbent assay (ELISA) in 47 patients with RA, 47 with osteoarthritis (OA), 24 with systemic lupus erythematosus (SLE), 24 with inflammatory bowel disease (IBD), and in 47 healthy controls. A disease activity score was assessed in the patients with RA, SLE, and IBD.
The plasma level of HC gp-39 in the RA patient group was significantly higher than in the other patient groups and healthy controls. The level in patients with OA, SLE, and IBD was also significantly higher than the HC gp-39 level found in the healthy control group. HC gp-39 levels in patients with RA correlated positively with the ESR and IgM rheumatoid factor level but not with other variables of disease activity. In the patients with SLE and IBD no correlation was found with the disease activity score.
The plasma level of HC gp-39 is increased in inflammatory conditions with and without joint disease (SLE, IBD, OA, and RA). Thus increased levels of HC gp-39 do not only reflect joint disease but also reflect inflammation or tissue degradation in various conditions. Notably, the highest level of HC gp-39 was found in patients with RA. Only in the RA patient group was a correlation between HC gp-39 plasma levels and some laboratory variables of disease activity found.
Annals of the Rheumatic Diseases 08/2000; 59(7):544-8. · 10.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective
To investigate the expression of human cartilage (HC) gp-39, a possible autoantigen in rheumatoid arthritis (RA), in peripheral blood and synovium, to characterize its cellular source, and to analyze correlations with clinical features.Methods
The expression of HC gp-39 in synovium and peripheral blood mononuclear cells (PBMC) was assessed by immunohistochemistry and flow cytometry. Synthesis and secretion were investigated by both reverse transcription–polymerase chain reaction and enzyme-linked immunosorbent assay.ResultsPBMC expressing HC gp-39 were increased in RA patients compared with spondylarthropathy patients (P = 0.0029) and with healthy control subjects (P = 0.0013). HC gp-39+ cells were also slightly overrepresented in RA synovium (P = 0.01). In both blood and synovium, HC gp-39+ cells were identified as CD14dim,CD16+ monocytes, a phenotype which can differentiate from classic CD14++ monocytes by maturation in vitro. HC gp-39 messenger RNA was detected in RA synovium and PBMC, and PBMC secreted HC gp-39 in vitro. The number of HC gp-39+ PBMC correlated with serum levels of C-reactive protein (r = 0.39, P = 0.003) and HC gp-39 (r = 0.52, P = 0.014). HC gp-39 expression in RA synovial lining correlated with joint destruction (r = 0.77, P < 0.001).ConclusionCD16+ monocytes, a cellular source of HC gp-39 in vivo, are overrepresented in both RA peripheral blood and synovial tissue. The presence of HC gp-39+ cells in RA synovium is correlated with the degree of joint destruction. These data support a role of these cells in the local autoimmune response that leads to chronic inflammation and joint destruction.
[Show abstract][Hide abstract] ABSTRACT: Monoclonal antibodies (mAb) specific for the clonotype of an autoreactive T cell may be useful reagents in the modulation of autoimmune disease. We have previously reported the generation of a set of mAb specific for the clonotypic structure of a human T-cell clone recognizing an epitope of human cartilage gp-39. This glycoprotein was recently identified as a candidate autoantigen in rheumatoid arthritis. Here, we demonstrate for the first time that small amounts of immobilized anticlonotype mAb can induce anergy in the autoreactive clone. Following the anergic stimulus, T cells failed to proliferate upon restimulation as a result of a lack of interleukin-2 (IL-2) gene transcription. In addition, a diminished interferon-gamma (IFN-gamma) production was found. Our data indicate that anergy was not a result of T-cell receptor (TCR) downmodulation or the absence of free TCR. The anergic state was induced independent of costimulation or the presence of IL-2 and no protein synthesis was required for the induction of anergy. Anticlonotype mAb-induced anergy was prevented by cyclosporin A, suggesting that active signalling via the calcium/calcineurin pathway was required for the induction of anergy. In coculture experiments, anergic T cells were found to suppress the response of reactive cells from the same clone. This bystander suppression led to 90% inhibition of peptide-induced proliferation. Together, these findings suggest that mAb to the clonotypic structure of autoreactive T cells may be suitable reagents for the functional inactivation of these T cells in autoimmune diseases.
[Show abstract][Hide abstract] ABSTRACT: Monoclonal antibodies (mAb) directed against the clonotypic structure of the T-cell receptor (TCR) may be useful reagents in the study and therapy of T-cell-mediated diseases. In contrast to several reports concerning the generation of anti-clonotype mAb to mouse TCR, only very limited numbers of anti-clonotype mAb to human TCR have been described. So far, a suitable method for the generation of anti-clonotype mAb to a given TCR has not been available and in this report we describe a novel strategy for the generation of such mAb. Mice were immunized with intact human T-cells. Then. spleen cell populations were precleared from B-cells reactive to CD3 and the constant region of the TCR by adsorption to TCR/CD3 complexes derived from an irrelevant T-cell clone. Subsequently, clonotype-specific B-cells were selected with TCR/CD3 complexes from the T-cell clone of interest. The small number of B-cells resulting from this selection were clonally expanded in a B-cell culture system and then immortalized by mini-electrofusion. Ten clonotype-specific mAb were generated against a DRB1*0401-restricted T-cell clone recognizing an epitope of the human cartilage glycoprotein 39 (HC gp-39). All mAb immunoprecipitated a heterodimeric 85 kDa protein. Absolute specificity was demonstrated in a T-cell agglutination test with the T-cell clone of interest compared to a set of 16 defined, irrelevant T-cell clones or lines. In functional assays, the mAb were found to inhibit or block antigen-specific T-cell stimulation. In addition, crosslinked mAb were found to stimulate proliferation of the specific clone in the absence of antigen and antigen presenting cells (APC). Such mAb may have clinical relevance in deleting or modulating autoreactive T-cells in a clonotype-specific manner.
[Show abstract][Hide abstract] ABSTRACT: Human anti-cytomegalovirus (CMV) specific B cells were enriched to a purity of up to 38% on CMV-coated dishes and subsequently clonally expanded in the presence of human T cell supernatant and irradiated murine thymoma helper cells. The expanded cells were immortalized by a mini-electrofusion with K6H6B5 myeloma cells. Twenty-two anti-CMV positive B cell clones could be obtained from as little as 1.5 ml donor blood. The majority of these clones produced anti-CMV antibodies of the IgG class. Ten anti-CMV positive B cell clones were submitted to separate mini-electrofusions yielding stable, human anti-CMV IgG-producing hybridomas in six out of ten fusions. These antibodies recognized different proteins of the CMV virus, as deduced from the immunofluorescence staining pattern on infected human fibroblasts.
Human antibodies and hybridomas 11/1993; 4(4):166-73.
[Show abstract][Hide abstract] ABSTRACT: This paper reports the generation of monoclonal antibody producing hybridomas from a small number of antigen-specific B cells selected by panning on antigen-coated dishes and rosetting with antigen-coupled paramagnetic beads. Anti-HIV positive B cells from spleen could be recovered by panning with an efficiency of 5% and a purity of 24%. Immunobead selection of anti-HIV positive B cells from the same mice yielded a recovery of 17% and a purity of 7%. Various experimental conditions with respect to the selection of specific B cells were investigated, leading to an optimized protocol for the isolation of a limited subset of B cells. The selected cells retained their property to produce immunoglobulins and could be clonally expanded in the presence of human T cell supernatant and irradiated murine thymoma helper cells to generate sufficient cells for a mini-electrofusion with NS-1 myeloma cells. Up to 78 specific hybridomas could be generated from one anti-HIV positive B cell. An overall efficiency of specific B cell immortalization of up to 10% was obtained.
[Show abstract][Hide abstract] ABSTRACT: A new and very efficient method for the generation of human and murine monoclonal antibodies has been developed. The method is based on clonal expansion of single B cells in the presence of human T cell supernatant and irradiated murine thymoma helper cells. Subsequently, the clonally expanded B cells are immortalized by electric field mediated cell fusion. The high efficiency of the method permits the processing of small numbers of lymphocytes, e.g., obtained by preselection of specific B cells, small amounts of human donor material and murine PBL or lymph node cells. The method may be an alternative for the EBV-transformation technique used for the generation of human monoclonal antibodies, which immortalizes only a subset of B cells and frequently yields poorly growing or unstable cell lines. This report describes the generation of murine anti-HIV and human anti-rubella antibodies combining the clonal expansion of B cells and mini-electrofusion.