Cellular immune response to human cartilage glycoprotein-39 (HC gp-39)-derived peptides in rheumatoid arthritis and other inflammatory conditions

OBJECTIVE

To study the specificity of the peripheral blood mononuclear cell (PBMC) response to peptides derived from human cartilage glycoprotein-39 (HC gp-39) in patients with rheumatoid arthritis (RA) and the correlation between this response and disease activity.

METHODS

RA patients, patients with systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD) or osteoarthritis (OA) and healthy controls were studied. All individuals were typed for HLA-DRB1 and their disease activity score was documented. Proliferation of PBMC was measured following incubation with five different HC gp-39-derived peptides, selected by the use of a DR4 (DRB1*0401) binding motif.

RESULTS

A proliferative response to one of the five peptides (peptide 259-271 at 10 microg/ml) was more often observed in RA patients than in healthy controls (P=0.001). RA patients who expressed DRB1*0401 more often showed a response against this peptide than RA patients who did not express this RA-associated haplotype. This response was not RA-specific since patients with IBD or OA also showed a response significantly more frequently than healthy controls (P:=0.02 and P=0.03 respectively). However, the level of the response against peptide 259-271 correlated with disease activity in RA patients but not in patients with IBD or SLE. Increased responses to HC gp-39 263-275 were found in patients with IBD or OA; a trend towards such a response failed to reach significance in RA patients in this study.

CONCLUSION

In RA patients as well as in patients with other inflammatory conditions, HC gp-39-derived peptides may be targets of the T-cell-mediated immune response. In the RA patient group the immune response to HC gp-39-derived peptide 259-271 correlated with disease activity.

Raised human cartilage glycoprotein-39 plasma levels in patients with rheumatoid arthritis and other inflammatory conditions

OBJECTIVE

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.

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Human cartilage gp-39+,CD16+ monocytes in peripheral blood and synovium: correlation with joint destruction in rheumatoid arthritis

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.

RESULTS

PBMC 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).

CONCLUSION

CD16+ 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.

Induction of tolerance with intranasal administration of human cartilage gp-39 in DBA/1 mice: amelioration of clinical, histologic, and radiologic signs of type II collagen-induced arthritis

OBJECTIVE

Human cartilage glycoprotein 39 (HC gp-39) was recently identified as a candidate autoantigen in the pathogenesis of rheumatoid arthritis. In the present studies, we investigated the capacity of HC gp-39 to interfere in clinical disease induced by an unrelated autoantigen, type II collagen (CII), by the induction of cross-tolerance.

METHODS

DBA-1j/Bom mice were immunized with bovine CII/complete Freund's adjuvant and were given intraperitoneal booster injections of CII on day 21. Tolerance was induced via the intranasal pathway with either the disease-inducing antigen (CII), a control antigen (ovalbumin), or HC gp-39 either before priming with CII or near the day of the booster injection. Arthritis was monitored visually, and joint pathology was examined histologically and radiologically. In addition, CII antibody levels in serum were analyzed by enzyme-linked immunosorbent assay.

RESULTS

In contrast to treatment before priming, intranasal application of HC gp-39 after immunization markedly suppressed disease activity and prevented joint destruction, whereas application of ovalbumin or CII was ineffective. Interference of HC gp-39 with the immune response to CII was demonstrated by decreased anti-CII antibody levels. The combined data indicate that intranasal treatment with HC gp-39 may trigger modulatory or regulatory mechanisms that interfere with the expression of disease in murine collagen-induced arthritis.

CONCLUSION

HC gp-39 is the first cross-tolerance-inducing protein in arthritis that down-modulates a spectrum of disease features when given in a semitherapeutic protocol.

Intranasally induced immunological tolerance is determined by characteristics of the draining lymph nodes: studies with OVA and human cartilage gp-39

Mucosal tolerance is a naturally occurring immunological phenomenon that prevents harmful inflammatory responses to ingested or inhaled environmental, predominantly nondangerous, Ags. The nasal mucosa is an extremely efficient compartment in the induction of immunological tolerance which can be exploited in Ag-specific treatment of autoimmune disease. With the use of a model Ag (OVA) and an Ag implicated in the autoimmune disease rheumatoid arthritis (human cartilage gp-39), we here show in a mouse model that the superficial cervical and internal jugular lymph nodes that drain the nasal mucosa are instrumental in the induction of tolerance. Removal of these lymph nodes abrogates tolerance induction, which can be restored by transplantation of superficial cervical lymph nodes, but not of peripheral lymph nodes. The results indicate that lymph nodes that directly drain the nasal mucosa constitute a unique microenvironment which favors the induction of immunological tolerance.

Poor expression of T cell-derived cytokines and activation and proliferation markers in early rheumatoid synovial tissue

We compared the state of activation and proliferation of T cells in synovial tissue (ST) from rheumatoid arthritis (RA) patients in early and late stages of the disease to find out whether T-cell-driven immune responses vary during the course of the disease. ST was obtained from 12 patients with early RA (< 1 year) and 12 patients with longstanding RA (> 5 years). T cells and interferon-gamma (IFN-gamma)-positive cells were detected in ST using immunohistologic methods. To determine the percentage of T cells expressing the interleukin-2 receptor, IFN-gamma, or the proliferation associated antigen Ki-67, immunofluorescence double-staining techniques were used. The scores for the number of T cells and for the expression of IFN-gamma as well as the percentages of T cells expressing CD25, IFN-gamma, or Ki-67 in rheumatoid synovium were not dependent on disease duration. These results do not support the assumption that the responsiveness of T cells in ST of RA patients differs between early and late stages of the disease. The data indicate that at present no arguments exist that the effect of T-cell-directed interventions on synovial inflammation might vary in different stages of the disease.

Methotrexate reduces inflammatory cell numbers, expression of monokines and of adhesion molecules in synovial tissue of patients with rheumatoid arthritis

Methotrexate (MTX) is one of the most widely prescribed drugs in the treatment of rheumatoid arthritis (RA). The mechanism by which MTX exerts its anti-rheumatic effect has not yet been defined. The aim of the present study was to investigate the effect of MTX treatment (7.5-15 mg/week) on synovial tissue in RA. For this purpose, synovial biopsies were taken from 11 RA patients before and 16 weeks after initiation of MTX therapy. Immunohistochemistry was performed using monoclonal antibodies (MAb) specific for CD3, CD4, CD8, CD22, CD25, CD38, CD68, MAb67, Ki67, interferon gamma (IFN-gamma), interleukin (IL)-1alpha, IL-1beta, tumour necrosis factor alpha (TNF-alpha), E-selectin, ICAM-1 and VCAM-1. All parameters for disease activity improved during the period of treatment. Immunohistochemical analysis revealed a statistically significant decrease in scores for CD3, CD8, CD38, CD68, Ki67, IL-1beta, TNF-alpha and the adhesion molecules E-selectin and VCAM-1. The observed decrease in synovial scores for inflammatory cells, monokines and adhesion molecules suggests that the anti-inflammatory effect of MTX is, in part, dependent on a reduction in monokine-inducible vascular adhesion molecules and subsequent reduction of cell traffic into joints.

Distribution of T cells and signs of T-cell activation in the rheumatoid joint: implications for semiquantitative comparative histology

A prerequisite for comparative histology of synovial tissue by means of biopsies is insight into the distribution of a marker under study. This investigation focuses on the variation in the presence of T cells and signs of T-cell activation within the rheumatoid joint. For this purpose, multiple slides from several pieces of synovial tissue from different parts of a joint were stained and scored for the expression of CD3, CD25, HLA-DR, Ki67 and interferon-gamma. The variation in scores for the presence of T cells and markers of activation was more pronounced in slides prepared from different pieces of tissue than in slides from one piece of tissue. Based on multiple analysis of variance, methods are suggested to establish a reliable overall score for the expression of a certain marker within a joint. Following validation, such methods may prove to be useful by allowing semiquantitative histology of synovial tissue for studies on arthritis.

Sesame oil in injectable gold: two drugs in one?

To investigate the potential anti-inflammatory effects of sesame oil, which is present in the injectable gold preparation Auromyose, the synthesis of tumour necrosis factor alpha (TNF-alpha), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) by in vitro stimulated blood cells was measured before, during and after 12 weeks of dietary supplementation with 18 g of sesame oil daily in 11 healthy male volunteers. Neither TNF-alpha, PGE2 nor LTB4 production levels showed statistically significant changes during the 12 weeks of dietary supplementation with sesame oil. These results do not suggest an anti-inflammatory effect of sesame oil as present in injectable gold preparations which are used in the treatment of rheumatoid arthritis.

Human cartilage glycoprotein-39 as a candidate autoantigen in rheumatoid arthritis

OBJECTIVE

To identify a cartilage-derived autoantigen that is relevant to the rheumatoid arthritis (RA) disease process.

METHODS

A DR4 (DRB1*0401) peptide binding motif was used for the selection of potential self reactive peptides within human cartilage glycoprotein-39 (HC gp-39), a protein that is differentially expressed at the site of chronic inflammation. Synthetic peptides accommodating the motif were tested for binding the RA-associated DR4 (DRB1*0401) molecules. High-affinity binders were then tested for their capacity to stimulate peripheral blood mononuclear cell responses in RA patients or healthy donors. To assess the arthritogenic nature of native HC gp-39, the protein was injected into BALB/c mice.

RESULTS

HC gp-39-derived motif-based peptides were selectively recognized by peripheral blood T cells from RA patients. Injection of the intact protein into BALB/c mice resulted in immunity to HC gp-39, which was found to be associated with the development of a chronic, relapsing arthritis. Moreover, inhalation of the protein led to tolerization of antigen-specific T cells and to suppression of HC gp-39-induced arthritis.

CONCLUSION

These data indicate that HC gp-39 is a target of the immune response in RA. Consequently, HC gp-39 is a candidate for antigen-specific immunotherapy.

Treatment with a chimeric CD4 monoclonal antibody is associated with a relative loss of CD4+/CD45RA+ cells in patients with rheumatoid arthritis

This study investigates immunogenicity and in vivo effects on T-cells of long-term CD4 monoclonal antibody treatment of patients with rheumatoid arthritis. Patients were treated with several dosage regimens of a chimeric CD4 monoclonal antibody entitled cM-T412 over the course of 1 year. The circulating CD4+ T-cell count sharply decreased after the first cM-T412 injection and slowly recovered after the last injection. Within the CD4+ subset there was a selective depletion of CD45RA+ T cells, HLA-DR+, and CD25+ cells, providing evidence that activated/memory CD4+ cells resist the effect of CD4 monoclonal antibodies. Studies on cytokine production by peripheral blood mononuclear cells cultures in vitro revealed no differential effect on the production of interleukin-4 compared to interferon-gamma, indicating that a shift from a Th1 to a Th2 lymphokine production profile was not achieved. Human anti-monoclonal antibodies (HAMA) were induced in a minority of the patients predominantly after the first treatment course. All the sera containing HAMA specifically inhibited the binding of cM-T412 to T-cells. However, HAMA formation does not interfere with the biological effect of repeated cM-T412 administration since the degree of CD4 depletion following repeated administration of cM-T412 to patients with and without blocking antibodies was similar. We conclude that the currently available data are of critical importance in the interpretation of the obtained clinical experience and for further development of this therapeutic strategy.

Shift toward T lymphocytes with a T helper 1 cytokine-secretion profile in the joints of patients with rheumatoid arthritis

OBJECTIVE

To investigate whether T cells in the inflamed joints of patients with rheumatoid arthritis (RA) preferentially produce the T helper 1 (Th1) cytokines, interferon-gamma (IFN gamma) and interleukin-2 (IL-2), or the Th2 cytokine, IL-4, when compared with corresponding peripheral blood-derived T cells.

METHODS

Synovial fluid mononuclear cells (SFMC) and corresponding peripheral blood mononuclear cells (PBMC) from 10 patients with RA were analyzed, either directly or after in vitro stimulation, for the intracellular presence of Th1 and Th2 cytokines. The amount of secreted cytokine in the cell culture supernatants was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

IFN gamma-containing cells were detected in the unstimulated SFMC, but not in the PBMC, of 3 patients with RA. Cells positive for IL-2 or IL-4 were not detected in the unstimulated samples. Following stimulation, the mean percentage of cells containing Th1 cytokines was significantly increased in the SFMC compared with the PBMC; no differences were found in the mean percentage of IL-4-containing cells. A comparable shift toward Th1 cytokines was observed when the amount of secreted cytokine was determined by ELISA.

CONCLUSION

A shift toward T cells with a Th1 cytokine profile was observed in the joints of patients with RA. Since an imbalance between Th1 and Th2 cells is thought to be of pathogenic significance, this finding might have implications for the development of new therapies for RA.

Persistent CD3-crosslinking down-regulates interleukin-2 responsiveness in interleukin-2-competent cloned T cells: the possible involvement of protein kinase C

To investigate the regulation of interleukin-2 (IL-2) responsiveness of T cells, a human CD4+ T-cell clone with constitutive expression of IL-2 receptors was stimulated with recombinant IL-2 (rIL-2) in the presence or absence of immobilized anti-CD3 monoclonal antibodies (alpha CD3imm MoAb). Incubation of T cells with alpha CD3imm MoAb decreased IL-2-induced proliferation which could not be ascribed to the modulation of IL-2 receptor expression nor to cell death. Phorbol-myristate-acetate (PMA), an activator of protein kinase C (PKC), also induced down-regulation of IL-2 responsiveness. The alpha CD3sol MoAb, inducing Ca(2+)-mobilization without activating PKC, did not inhibit IL-2 responsiveness whereas cyclosporine A (CsA), a drug that inhibits the Ca(2+)-dependent activation pathway, did not prevent the induction of IL-2 hyporesponsiveness induced by alpha CD3imm MoAb. It is concluded that modulation of IL-2 responsiveness of T cells via the T-cell receptor/CD3 complex (TCR/CD3) may be mediated by a PKC-activating signal.

The tetracycline derivative minocycline differentially affects cytokine production by monocytes and T lymphocytes

Minocycline is a tetracycline derivative that has beneficial effects in noninfectious forms of arthritis and dermatitis. To investigate whether this effect may be attributed to interference with cytokine production, we studied the effect of minocycline on cytokine production by T cells and monocytes. Minocycline exerted an inhibitory effect on tumor necrosis factor alpha (TNF-alpha) and gamma interferon production by stimulated T cells, whereas the production of interleukin 6 (IL-6) remained unaffected. The effect of minocycline on TNF-alpha mRNA synthesis by T cells was shown to be stimulus specific. T cells stimulated by a Ca2+-independent mode exhibited a decrease in TNF-alpha mRNA in the presence of minocycline, whereas the TNF-alpha mRNA level remained unaffected by minocycline when cells were stimulated in a Ca2+-dependent manner. In contrast to the effect on T cells, addition of minocycline to lipopolysaccharide-stimulated monocytes led to a dose-dependent increase in TNF-alpha and IL-6 production which was paralleled by an enhancement of TNF-alpha mRNA synthesis. These results indicate that minocycline exerts differential effects on the regulation of cytokine production by T cells and monocytes that are partly reflected at the mRNA level. Given the pleiotropic effects of minocycline, it is suggested that the immunostimulatory effect on monocytes might counteract its beneficial properties in the treatment of several forms of chronic inflammation.

Chloroquine combined with cyclosporine in rheumatoid arthritis: more than the addition of 2 drugs alone

Combination therapy in rheumatoid arthritis (RA) with 2 or more disease modifying antirheumatic drugs (DMARD) is theoretically attractive if the drugs exert additional or even synergistic effects and have different toxicity patterns to avoid cumulative toxicity. The combination of cyclosporin A (CsA) with chloroquine has shown in in vitro studies a synergistic ability to inhibit the proliferation of peripheral blood mononuclear cells and clonal T cells and the production of interferon gamma by clonal T cells. This synergy is probably based on different mechanisms of action of the 2 drugs: CsA primarily inhibits the production of interleukin 2 (IL-2) (and other cytokines) at the level of transcription, whereas chloroquine primarily inhibits the responsiveness of T cells to IL-2 stimulation. To evaluate whether these in vitro data can be extrapolated in vivo, a large 2 phase trial has been initiated in the Netherlands in which the combination of CsA with chloroquine is evaluated in patients with RA.

Increased expression of interferon (IFN)-gamma together with IFN-gamma receptor in the rheumatoid synovial membrane compared with synovium of patients with osteoarthritis

Data concerning the presence of T-cell-derived cytokines in the rheumatic joint are conflicting, challenging the hypothesis that rheumatoid arthritis (RA) is a T-cell-mediated disease. In this study synovial tissue specimens of 11 patients with RA and eight patients with osteoarthritis (OA) were stained for interferon-gamma (IFN-gamma) and its receptor. The level of expression of IFN-gamma was compared with that in tissue specimens of delayed-type hypersensitivity (DTH) reactions of the skin and of chronic tonsillitis. Furthermore, the percentage of T-lymphocytes which stained positive for IFN-gamma was determined using double staining techniques. IFN-gamma and its receptor were detected in all patients with RA and in 7/8 and 3/8, respectively, of patients with OA. Expression of IFN-gamma (P<0.02) and IFN-gamma receptor (P<0.01) in synovial tissue of patients with RA was more abundant compared with that in patients with OA. Although IFN-gamma could be detected in RA synovial tissue, the level of expression was less when compared with DTH reactions of the skin and tonsillitis. The percentage of CD3+ cells being positive for IFN-gamma was approximately 1% in RA, whereas in DTH reactions of the skin it was >90% and in tonsillitis approximately 30%. We conclude that the presence of IFN-gamma and its receptor in RA synovial tissue suggests a role for this cytokine in the ongoing immunological reaction of the inflamed joint.

Tenidap, but not nonsteroidal anti-inflammatory drugs, inhibits T-cell proliferation and cytokine induction

T-lymphocytes are involved in the inflammatory response that occurs in affected joints of patients with rheumatoid arthritis (RA). Some second-line disease modifying anti-rheumatic drugs used in the treatment of patients with RA are known to block T-cell activation. The present study assessed whether tenidap, an investigational anti-rheumatic drug, affects in vitro T-cell responses such as proliferation and cytokine production. It was found that tenidap, in contrast to several nonsteroidal anti-inflammatory drugs, inhibits anti-CD3 or IL-2 driven proliferative responses of cloned human T-cells. Furthermore, tenidap was found to inhibit IFN-gamma production as well as the induction of mRNA encoding IFN-gamma or TNF-alpha. The results indicate that tenidap may exert at least part of its anti-inflammatory activity via inhibition of T-cell function and cytokine production.

The influence of tetracyclines on T cell activation

Minocycline has been shown to have an anti-inflammatory effect in patients with rheumatoid arthritis (RA). Since there is evidence that RA is a T cell-mediated disease, we investigated the effect of minocycline on human T cell clones derived from the synovium of an RA patient. The T cells, when activated via the T cell receptor (TCR)/CD3 complex, were suppressed functionally by minocycline, resulting in a dose-dependent inhibition of T cell proliferation and reduction in production of IL-2, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha). Besides an inhibition of IL-2 production, minocycline exerted its effect on T cell proliferation by induction of a decreased IL-2 responsiveness. We showed that the chelating capacity of minocycline plays a crucial role in the inhibitory effect on T cell function, since the inhibitory effect on T cell proliferation could be annulled by addition of exogenous Ca2+. However, minocycline did not markedly influence the typical TCR/CD3-induced intracellular Ca2+ mobilization. Taken together, the results clearly indicate that minocycline has immunomodulating effects on human T cells.

Chloroquine inhibits T cell proliferation by interfering with IL-2 production and responsiveness

Chloroquine (Chl) is an anti-rheumatic drug that is widely used in the treatment of rheumatoid arthritis (RA). It seems that T cells are important in the pathogenesis of RA, but it is not known whether Chl acts via inhibition of T cell function. We here present evidence that Chl, just like cyclosporine A (CsA), inhibits T cell proliferation as induced with immobilized alpha CD3 MoAb in a concentration-dependent manner, at least partly through interfering with the production of IL-2 protein and the induction of IL-2 mRNA. Furthermore, Chl impedes the responsiveness of T cell clones to IL-2 since (1) the inhibition of alpha CD3 MoAb-induced proliferation by Chl could not be reversed by rIL-2 and (2) Chl directly blocks IL-2-driven proliferation of cloned T cells. Chl appeared to interfere with the internalization (50% inhibition) and degradation (total blockade) of rIL-2. Finally, the combination of Chl and CsA synergistically inhibited T cell proliferation. We conclude that Chl may inhibit functional properties of human T cells, although the drug is 100- to 1000-fold less potent than CsA in inhibiting T cell proliferation and IL-2 production, respectively. It is speculated that the in vitro effects of Chl might be relevant in explaining the anti-rheumatic effect of this drug in patients with RA.

Therapeutic regulation of T cells in rheumatoid arthritis

TCR repertoire studies in RA have yielded conflicting data. These studies were initiated on the premise that clonal expression of T cells at the site of inflammation could serve as a target for immune therapies designed on the basis of the option to inactivate or eliminate the presumed pathogenic T cells. These analyses have demonstrated the existence of a highly diverse overall TCR repertoire on the basis of extensive usage of TCR V genes both in synovial fluid and tissue. However, clusters of RA patients can be recognized who share increased usage frequencies of defined TCR V genes among synovial fluid or synovial tissue lymphocytes. Subsequent analysis of the CDR3 regions among diverse overall TCR repertoires have revealed the presence of conserved amino acid sequences in the CDR3 regions of the variable portions of TCRs in T lymphocytes derived from the site of inflammation. These findings suggest that a selective, antigen-driven expansion of T lymphocytes is occurring in the inflamed joints. Parallel to the TCR-repertoire studies, we investigated whether vaccines prepared from synovial T cells could modulate T-cell reactivity. The studies were based on previous work on TCV in animals, revealing that attenuated non-specific T-cell lines could serve as a vaccine. The results obtained in 13 RA patients showed no clear indication for a cellular or humoral immune response. Our experience with TCV in RA patients showed that this technique is feasible and safe. We found some evidence for a modulated T-cell reactivity both in vivo and in vitro. These results show at least some immunomodulatory effect af T-cell vaccination, although the antigen specificity of the effect of this intervention remains to be shown. Because of the convincing studies in animals and MS patients, further studies in RA should focus on the effect of vaccination using vaccines prepared from disease-inducing cells. In this respect, determination of the CDR3 regions of synovial T cells could lead to the identification of those T cells that are relevant for the disease.

Immobilized anti-CD3 antibody activates T cell clones to induce the production of interstitial collagenase, but not tissue inhibitor of metalloproteinases, in monocytic THP-1 cells and dermal fibroblasts

In this study we have investigated whether direct cell to cell contact between activated paraformaldehyde-fixed T cell clones obtained from synovial tissue of patients with osteoarthritis (OA) or rheumatoid arthritis and target monocytic cells or dermal fibroblasts influenced the balance between interstitial collagenase and its specific inhibitor tissue inhibitor of metalloproteinases (TIMP) produced by the latter cell types. PHA/PMA-activated fixed T cell clones or their membranes strongly induced the production of collagenase both in monocytic THP-1 cells and in dermal fibroblasts. In contrast, only low levels of TIMP were induced in THP-1 cells and no change of TIMP expression was observed in fibroblasts as a result of stimulation with PHA/PMA-activated T cells or T cell membranes. Anti-CD3-activated T cell clones stimulated the production of collagenase both in THP-1 cells and fibroblasts, whereas TIMP levels were not influenced. Collagenase production in THP-1 cells induced by anti-CD3-activated T cell clones was 1) dependent on the dose of anti-CD3 used to stimulate the T cells, 2) initiated only when CD3 was cross-linked, and 3) inhibited when cyclosporin A was included during T cell activation. Our data collectively indicate that activated T cells in contact with monocytic cells or fibroblasts may alter the balance between interstitial collagenase and its specific inhibitor TIMP. This selective induction of a mediator profile representative of matrix breakdown as a result of target cell interaction with activated T cells may be an important factor in the local process of tissue destruction that characterizes osteoarthritis and rheumatoid arthritis.

Immobilized anti-CD3 antibody activates T cell clones to induce the production of interstitial collagenase, but not tissue inhibitor of metalloproteinases, in monocytic THP-1 cells and dermal fibroblasts

In this study we have investigated whether direct cell to cell contact between activated paraformaldehyde-fixed T cell clones obtained from synovial tissue of patients with osteoarthritis (OA) or rheumatoid arthritis and target monocytic cells or dermal fibroblasts influenced the balance between interstitial collagenase and its specific inhibitor tissue inhibitor of metalloproteinases (TIMP) produced by the latter cell types. PHA/PMA-activated fixed T cell clones or their membranes strongly induced the production of collagenase both in monocytic THP-1 cells and in dermal fibroblasts. In contrast, only low levels of TIMP were induced in THP-1 cells and no change of TIMP expression was observed in fibroblasts as a result of stimulation with PHA/PMA-activated T cells or T cell membranes. Anti-CD3-activated T cell clones stimulated the production of collagenase both in THP-1 cells and fibroblasts, whereas TIMP levels were not influenced. Collagenase production in THP-1 cells induced by anti-CD3-activated T cell clones was 1) dependent on the dose of anti-CD3 used to stimulate the T cells, 2) initiated only when CD3 was cross-linked, and 3) inhibited when cyclosporin A was included during T cell activation. Our data collectively indicate that activated T cells in contact with monocytic cells or fibroblasts may alter the balance between interstitial collagenase and its specific inhibitor TIMP. This selective induction of a mediator profile representative of matrix breakdown as a result of target cell interaction with activated T cells may be an important factor in the local process of tissue destruction that characterizes osteoarthritis and rheumatoid arthritis.

Activated gelatinase-B (MMP-9) and urokinase-type plasminogen activator in synovial fluids of patients with arthritis. Correlation with clinical and experimental variables of inflammation

OBJECTIVE

To evaluate the occurrence of gelatinase-B (matrix metalloproteinase 9, MMP-9) in synovial fluids (SF) of patients with arthritis to investigate the possible role of this neutral MMP in joint destruction.

METHODS

In paired (series I) and unpaired SF (series II) we examined the occurrence of gelatinase-B, prostromelysin-1, and urokinase-type plasminogen activator (u-PA).

RESULTS

In the paired SF a parallelism between the presence of activated gelatinase-B and the local arthritis activity scores of the knees was observed. Activated gelatinase-B correlated well with the presence of stromelysin-1 and u-PA, 2 enzymes probably involved in the activation process of gelatinase-B. In the 2nd series, activated gelatinase-B was found in 56 SF samples, whereas 82 samples did not exhibit activated gelatinase-B. The SF samples with the activated form of gelatinase-B showed a significantly higher ability to induce permeability changes in cultured monolayers of human endothelial cells, had more myeloperoxidase activity--secreted by infiltrated leukocytes--and had higher u-PA antigen concentrations, compared to SF samples without the activated form of gelatinase-B.

CONCLUSION

Our data suggest that the presence of gelatinase-B is a reflection of the inflammatory condition of the joints of patients with arthritis, and that the activation of gelatinase-B in the joints, which may occur in a u-PA/plasmin dependent and/or a stromelysin dependent way, contributes to the progression of arthritis.

Treatment of rheumatoid arthritis with a chimeric CD4 monoclonal antibody (cM-T412): immunopharmacological aspects and mechanisms of action

To investigate the mechanisms of action underlying the therapeutic effect of CD4 monoclonal antibody therapy in rheumatoid arthritis (RA), clinical responses were compared with several laboratory parameters. Twenty-nine RA patients received either 10 mg, 50 mg or 100 mg of cM-T412, a chimeric CD4 MoAb, for 7 days. The CD4 binding sites on circulating lymphocytes were saturated directly with cM-T412 and serum levels of unbound cM-T412 accumulated towards day 7 of treatment only in the patients treated with 50 and 100 mg. The treatment induced an instant and prolonged depression of the number of circulating CD4+ cells, similar for all dosages. Clinical improvement was observed predominantly in the patients treated with 50 or 100 mg cM-T412 daily and did not correlate with changes in counts of circulating leucocyte subsets nor with changes in serum cytokine levels. An antiglobulin response against cM-T412 developed in a majority of the patients. Side effects on the first day of treatment were correlated with an increase of serum IL-6 levels. This study indicates that a favourable clinical effect of cM-T412 administration was associated with the presence of unbound cM-T412 in the circulation of RA patients. Therefore penetration of unbound cM-T412 into the site of inflammation might determine the therapeutic effect in RA.

Antiendothelial cell antibodies in systemic lupus erythematosus: enhanced antibody binding to interleukin-1-stimulated endothelium

IgG antiendothelial antibodies (IgG AEA), as measured by enzyme-linked immunosorbent assay, could be detected in serum samples of 38 out of 41 patients with systemic lupus erythematosus. Incubation of endothelial cells (EC) with interleukin-1 alpha (IL-1 alpha), in contrast to incubation with interferon gamma or tumor necrosis factor alpha, resulted in an enhanced IgG AEA binding. Immunoblotting revealed reactivity of AEA against a variety of EC antigens. The upregulation of IgG-AEA-binding reactivity to IL-1 alpha-stimulated EC was due to binding to antigens that were already expressed by unstimulated EC. The IgG-binding reactivity to both IL-1 alpha-stimulated and unstimulated EC was significantly higher in the serum of patients with joint or skin abnormalities as compared with patients without these manifestations. These data suggest that upregulated binding of IgG to EC induced by IL-1 alpha may play a role in immune vascular damage.

Detection of intracellular interferon-gamma by light microscopy using an immunoperoxidase technique: correlation with the corresponding mRNA and protein product

Identifying individual cytokine-producing cells may help to acquire insight into immunological processes. This study was designed to adapt a technique for the detection of individual cytokine-producing cells from an immunofluorescence to an immunoperoxidase staining procedure. The production of interferon-gamma (IFN-gamma) by anti-CD3-activated cloned human T cells was used as a model system. After the conditions for the staining procedure were optimized, the immunoperoxidase technique was slightly more sensitive than the immunofluorescence technique. The intracellular staining for IFN-gamma was preceded or paralleled by IFN-gamma mRNA production and followed by accumulation of IFN-gamma in the supernatant. It is concluded that intracellular IFN-gamma can easily be detected using an immunoperoxidase procedure. This procedure is highly sensitive and allows quantification of the production of multiple cytokines by counting the percentage of positively staining cells.

Levels of soluble receptors for tumor necrosis factor type I and type II in paired synovial fluids of arthritis patients

The objective of this study was to determine whether levels of soluble receptors for tumor necrosis factor type I and type II (sTNF-RI and sTNF-RII) as measured in paired synovial fluids (SF) of arthritis patients are associated with clinical or laboratory parameters of local inflammation. sTNF-RI and -RII were measured by ELISA. We found that sTNF-RI and -RII did not correlate with activity of local inflammation. sTNF-RI levels correlated with sTNF-RII concentrations. We concluded that sTNF-RI and -II did not represent markers for local disease activity in arthritis patients.

Cellular interactions between synovial T-cell clones from a patient with rheumatoid arthritis

The aim of this study was to investigate T-T cell interactions that may be involved in the pathogenesis of chronic synovitis. Two CD4+ T-cell clones, termed N16 and N18, sharing similar cytokine profiles were isolated from the synovial tissue of a patient with rheumatoid arthritis. Activated N16 cells induced proliferation of N18 cells in the absence of accessory cells, while the proliferative response of N18 cells to activated N18 cells depended on the presence of accessory cells. Whereas the response of N18 to activated N18 cells could be blocked by MoAbs against HLA class I and LFA-1 molecules, the response of N18 to activated N16 cells was only weakly affected, suggesting that the surface molecules involved in this interaction differed. Indeed, using MoAbs against CD3, CD4 and to a lesser extent CD2, proliferation of N18 to activated N16 cells was abrogated. These data provide a model for T-T cell interactions involved in the development of chronic synovitis.

Effects of inoculation with attenuated autologous T cells in patients with rheumatoid arthritis

Injection of attenuated autoimmune T cells, T cell vaccination, has been used successfully in the prevention and treatment of experimental animal autoimmune disease. In order to determine whether such a procedure might be applied in rheumatoid arthritis (RA), a phase I study was conducted in thirteen RA patients with a mean disease duration of 12.8 years. All patients received a subcutaneous injection of attenuated autologous T lymphocytes from a CD4 positive clone (n = 4) or line (n = 9) isolated from synovial tissue (n = 3) or synovial fluid (n = 10). No toxic side effects were observed. On the average the patients showed a slight decrease in disease activity which was most marked at 8 weeks after the injection. Specific immune reactivity against the injected T cells was not detected, with the possible exception of one patient who was vaccinated with a clone selected in vitro with antigen and whose disease had begun one year earlier. In this patient a clear decrease in disease activity occurred, which was associated with a decrease in mitogen-induced proliferation of her peripheral blood mononuclear cells and in titres of serum rheumatoid factors. The results of this study show that inoculation of RA patients with autologous T cells is technically feasible and non-toxic, and may be associated with clinical and immunological effects. The data suggest that the potential of T cell vaccination should be further explored in diseases with defined antigen reactivity.

Antibiotics as disease modifiers in arthritis

The tetracyclines, especially minocycline, are supposed to have antiarthritic properties. Their efficacy has been tested in open clinical studies on RA patients. Recently a double-blind placebo-controlled trial was performed which revealed the antirheumatic properties of minocycline. The mode of action of the tetracyclines in arthritis is unknown, but could be linked to the immunosuppressive activity seen in vitro. The antiproliferative effect of minocycline in cloned synovial T-cells is demonstrated; moreover IFN-gamma production in cloned synovial T-cells is inhibited by minocycline.

T cell receptor rearrangements in juvenile rheumatoid arthritis: a search for oligoclonality

Southern blot analysis of DNA from paired samples of synovial compartment (membrane and/or fluid) and peripheral blood T cells from nine children with juvenile rheumatoid arthritis (JRA) was carried out. Using a T cell receptor C beta probe, dominant TCR rearrangements were discovered in specimens from three patients: synovial fluid T cells from one, synovial fluid and synovial membrane cells from a second, and synovial membrane and peripheral blood cells from a third. The patient showing dominant bands in peripheral blood as well as in synovium was the only child in the series with systemic disease. Since non-specific T cell recruitment is likely to dilute antigen specific clones to low levels, the finding of dominant rearrangements in three of nine patients may indicate that oligoclonality is indeed a feature of JRA.

Activated synovial T cell clones from a patient with rheumatoid arthritis induce proliferation of autologous peripheral blood-derived T cells

In order to investigate cellular interactions involved in the development of human autoimmune disease, a synovial fluid-derived T cell clone reactive with mycobacterial antigens, termed k38, was employed as a stimulus for autologous peripheral blood mononuclear cells (PBMC). Stimulator cells were used either activated with immobilized OKT3 mAb or in a resting state. Activated k38 cells triggered PBMC to proliferate. A T cell line prepared by coculturing autologous PBMC with irradiated activated k38 cells proliferated upon stimulation with activated k38 cells in the presence of PBMC as a source of accessory cells, as did T cell clones that were subsequently isolated from this line. Blocking studies revealed that proliferation of the anti-k38 line and anti-k38 clones in response to stimulation with clone k38 could be inhibited by monoclonal antibodies against a variety of cellular determinants including HLA class I and LFA-1 beta. It was demonstrated that the antigen reactivity of clone k38 was modulated by the presence of anti-k38 clones. These data provide a model for understanding the cellular interactions that may take place in vivo in the evolution of the chronic synovial inflammatory process.

IgA anti-dsDNA antibodies in systemic lupus erythematosus: occurrence, incidence and association with clinical and laboratory variables of disease activity

The relationship between IgA anti-dsDNA antibodies and systemic lupus erythematosus (SLE) disease activity was investigated. IgA anti-dsDNA antibodies were measured using ELISA techniques. Elevated serum levels of IgA anti-dsDNA antibodies were detected in 51% of the patients with SLE (n = 57) and 8% of the diseased controls (n = 214). The presence of IgA anti-dsDNA antibodies was associated with kidney and joint abnormalities, with hypocomplementemia and with circulating immune complexes. We conclude that increased levels of IgA anti-dsDNA antibodies are associated with disease activity in patients with SLE.

Cyclosporine and chloroquine synergistically inhibit the interferon-gamma production by CD4 positive and CD8 positive synovial T cell clones derived from a patient with rheumatoid arthritis

OBJECTIVE

To investigate synergistic interaction between cyclosporine (Cy) and chloroquine (Chl) in an in vitro system, with regard to interferon-gamma (IFN) production by OKT3 activated T cell clones.

METHODS

CD4+ and CD8+ T cell clones, derived from synovial tissue of a patient with rheumatoid arthritis (RA) were activated with plastic coated OKT3 monoclonal antibody in the presence or absence of various concentrations of Cy, Chl and their combinations. After 24 h of incubation the supernatants were assayed for IFN by ELISA:

RESULTS

Cy as well as Chl were able to completely inhibit in a concentration dependent fashion the IFN production by CD4+ and CD8+ T cell clones. Combinations of Cy and Chl, which in themselves give minor inhibition of IFN production, were able to inhibit in a synergistically enhanced fashion the production of IFN by these clones. The synergy was formally proven by the construction of isoboles. This synergy was most pronounced when drug concentrations were used which individually gave minor inhibition of IFN production.

CONCLUSION

We conclude that the results of our in vitro experiments may give rise to further investigation of the promising combination of Cy and Chl in the treatment of RA.

T Cells Cloned from Human Rheumatoid Synovial Membrane Functionally Represent the Th 1 Subset

The presence of activated T cells in the synovial membrane of patients with rheumatoid arthritis (RA) suggests a role for these cells in the pathogenesis of the disease. Recent evidence indicates that human T cells may fall into functional categories dependent on their cytokine profile and cytotoxic capacity. The human Th1 subset is cytolytic and produces high levels of IFN-gamma whereas the Th2 type of T cell produces IL-4. In order to investigate whether Th1 or Th2 type cells are present in the inflammatory synovial membrane in RA, a panel of synovial membrane derived T-cell clones (n = 19) was generated and studied functionally. Anti-CD3-induced cytotoxicity assays were performed to demonstrate the cytotoxic potential of clones. Except for two, all clones were cytolytic in this test. Clone cells were activated to initiate cytokine production and assessment of the cytokine levels showed that all clones produced large amounts of IFN-gamma (18 out of 19 clones: over 50,000 pg/ml) whereas IL-4 was absent or present in minimal amounts (17 out of 19 clones: less than 1000 pg/ml). The production of IL-1, IL-2 and IL-6 was variable. The functional characteristics of the clones studied indicate that they may resemble the Th1 subtype of T cells. Our data suggest a relation between Th1-type functions the chronic inflammation characteristic of RA.

T-cell receptor beta-chain gene rearrangements of T-cell populations expanded from multiple sites of synovial tissue obtained from a patient with rheumatoid arthritis

In this study T-cell receptor (TcR) beta-chain gene rearrangements of T-cell lines prepared from multiple sites (n = 92) of synovial tissue derived from both knees of a patient with rheumatoid arthritis were analysed. In the majority of T-cell lines, dominant TcR beta-chain gene rearrangements were detected, involving C beta 1 as well as C beta 2. The dominant rearrangement patterns of T-cell lines from different tissue fragments showed significant variability, but some of the DNA restriction fragments were shared by T-cell lines from multiple sites in both knees. The latter observation suggests that identical T-cell clones may be present at different sites in the synovial tissue and in different joints. However, since many T-cell lines yielded different rearrangement patterns, these data also indicate considerable heterogeneity of T cells in the joints. Apart from theoretical implications, this TcR heterogeneity of T cells within an individual patient also has practical consequences for studies on synovial T cells obtained by biopsy.

Interleukin-6 activity in paired samples of synovial fluid. Correlation of synovial fluid interleukin-6 levels with clinical and laboratory parameters of inflammation

Paired synovial fluid (SF) samples obtained from the knees of 12 arthritis patients were studied to establish a relation between parameters of local inflammatory activity and SF interleukin-6 (IL-6) levels. Local disease activity was scored using joint temperature, swelling and pain as clinical parameters of inflammation. SF samples were assayed for laboratory parameters of inflammation such as leucocyte content, the percentage polymorphonuclear cells, the pH, and for immunoglobulin levels (IgG, IgM). SF IL-6 concentrations were determined using the B9-bioassay. Within individual patients the local activity of inflammation as measured using clinical parameters was found to be related to the local SF IL-6 level. When considering the total group of patients, a correlation (P less than 0.001) was found between the clinical parameters of local inflammation and the SF IL-6 levels. Furthermore, IL-6 levels were found to correlate with leucocyte counts (P less than 0.02), the percentage of polymorphonuclear cells (P less than 0.10), the pH value (P less than 0.01), but not with SF IgM and IgG concentrations.

Cytomegalovirus induced PMN adherence in relation to an ELAM-1 antigen present on infected endothelial cell monolayers

In human umbilical vein endothelial cells infected with cytomegalovirus (CMV), an activation antigen recognized by monoclonal antibody (mAb) ENA1 appeared. mAb ENA1 reacts with an inducible endothelial surface antigen which has characteristics similar to those of ELAM-1. Incubation with anti-IL-1 partly inhibited this appearance and, parallel to this, the virus-induced polymorphonuclear cell (PMN) adhesion was decreased. In addition, the adhesion of PMN to virus-infected endothelial cells could be reduced by F(ab)2 fragments of mAb ENA1 to almost control level. The results obtained after incubation of PMN with mAb IB4 (against CD18) suggest that the adhesion of PMN to uninfected endothelial cells is CD18 glycoprotein dependent, and virus infection up-regulates this glycoprotein-dependent mechanism. These results indicate that the virus-induced PMN adhesion is regulated by the following mechanism: virus infection of endothelial cells induces IL-1 production, and the autocrine IL-1 causes the expression of ELAM-1 on the surface of endothelial cells. In turn this activation antigen ELAM-1 binds with its putative ligand present on the PMN membrane. The virus-induced PMN adhesion occurs also through a CD18 glycoprotein-dependent mechanism.

Lack of T cell oligoclonality in enzyme-digested synovial tissue and in synovial fluid in most patients with rheumatoid arthritis

The dominant presence of specific T-cell populations in the rheumatoid joint as detected by Southern blot analysis of T cell receptor (TCR) gene rearrangements would indicate local antigen recognition and T cell proliferation. We therefore studied TCR beta chain gene rearrangements using a C beta 2 probe in paired samples of T cell populations from synovial tissue and peripheral blood (n = 6) as well as synovial fluid (n = 16) and peripheral blood (n = 18) of patients with rheumatoid arthritis (RA). Peripheral blood mononuclear cells from healthy donors (n = 7) served as a control. T cells were studied directly after isolation or after non-specific expansion with OKT3 monoclonal antibody (MoAb) and T cell growth factor (TCGF). DNA samples were digested with EcoRI and HindIII to detect rearrangements to C beta 1 and C beta 2, respectively. Extra bands were detected in all EcoRI-digested DNA samples prepared from both freshly isolated and non-specifically expanded T cell populations of patients and healthy donors, possibly representing 'common' (V-) D-J rearrangements. Dominant rearrangements were found in only two out of 16 synovial fluid T cell populations (one freshly isolated and one expanded) and not in peripheral blood or synovial tissue derived T cell populations. No extra bands were detected in HindIII-digested DNA samples. To investigate the effect of in vitro culture techniques on rearrangement patterns we studied DNA samples prepared from synovial tissue T cells obtained both by outgrowth from tissue with TCGF or by enzyme digestion and subsequent expansion either with TCGF or with OKT3 MoAb and TCGF. Whereas the latter T cell population yielded 'common' rearrangements, the former T cell populations yielded different dominant rearrangements. These data indicate that oligoclonality of the T cell populations in synovial tissue and synovial fluid of patients with RA is a rare event. The data also show the influence of in vitro culture techniques on the result of TCR gene rearrangement analysis.

Cytolytic activity in T cell clones derived from human synovial rheumatoid membrane: inhibition by synovial fluid

A panel of T cell clones was derived from the synovial membrane of a patient with rheumatoid arthritis (RA). We investigated whether T cell clones with cytolytic properties were present and whether T cell cytotoxicity was influenced by the presence of synovial fluid. These issues were studied using anti-CD3 and lectin-induced cytotoxicity assays. The majority of the T cell clones derived from the synovial membrane showed cytotoxic properties although non-cytotoxic clones were also found. Three clones (N11, N6 and N15) showed strong cytotoxicity (more than 40% lysis at an effector-to-target cell ratio of 10:1) whereas three clones (N16, N4 and N14) were non-cytotoxic (less than 20% lysis at an effector-to-target cell ratio of 10:1). The induction of cytotoxicity in the anti-CD3-driven system was shown to be dependent on the dose of anti-CD3 present. When synovial fluid was added to these assays a strong inhibition of cytotoxicity was found. This inhibition of cytotoxicity was found with synovial fluid samples of RA patients, as well as with non-RA synovial fluids. Both anti-CD3 and lectin-dependent cytotoxicity assays were strongly inhibited. In conclusion, T cell clones with cytotoxic activity can be isolated from rheumatoid synovial membrane. In the presence of synovial fluid these cytotoxic cells are inhibited to exert their cytotoxic function.

Renal allograft-infiltrated lymphocytes and proximal tubular cells: further analysis of donor-specific lysis

We obtained both graft-infiltrating cells of host origin and proximal tubular epithelial cells (PTEC) of donor origin (using a selective serum-free medium) simultaneously from biopsies of rejecting renal allografts. The identity of PTEC cultures was established with monoclonal antibodies. Major histocompatibility complex class I expression could be upregulated and major histocompatibility complex class II expression induced on PTEC by 24- to 48-hr incubation with 200 U interferon-gamma. Graft-infiltrating cells were shown to lyse PTEC grown from the corresponding biopsy and not PTEC from biopsies from other patients. Therefore the lytic activity appeared to be donor-specific. Preincubation of PTEC with interferon-gamma did not consistently increase PTEC lysis. Lysis by graft-infiltrating cells obtained from four patients could be blocked by target-preincubation with anti-class I monoclonal antibodies, in one case both anti-class I and anti-class II monoclonal antibodies could block PTEC lysis. Blocking could also be obtained with anti-CD3 monoclonal antibody. PTEC lysis occurred only with graft-infiltrating cells cultured from biopsies with cellular interstitial rejection. So, PTEC seem to be a target in renal allograft rejection both in vivo and in vitro. This model system may be useful for further studies of cellular interactions between graft-infiltrating cells and their targets.

Dominant T-cell receptor beta-chain gene rearrangements indicate clonal expansion in the rheumatoid joint

T-cell receptor (TcR) beta and delta gene rearrangements were studied in anti-CD3 expanded T-cell populations cultured from the synovial membrane (SM) (n = 5) or synovial fluid (SF) (n = 2) of rheumatoid arthritis (RA) patients. Dominant TcR beta-chain gene rearrangements to C beta 1 were demonstrated in all the patients tested and 1-3 expanded clones per patient were found. Clonal rearrangements to C beta 2 were detected in one SM sample (two clones) and one SF sample (one clone). The TcR delta gene was deleted in all the samples tested. We conclude that clonal dominance may be found in expanded T-cell populations from SM and SF of RA patients. Multiple clones may be present, either using the C beta 1 or C beta 2 gene segment.

Induction of antibody-dependent cellular cytotoxicity against endothelial cells by renal transplantation

Antibodies that induce antibody-dependent cellular cytotoxicity (ADCC) of human umbilical-vein endothelial cells (EC) were detected using serum of a renal transplant patient who had experienced a severe vascular rejection episode after receiving an HLA-identical kidney graft from a living-related donor. This reactivity was absent in sera obtained before transplantation. The antibody nature of the reactivity present in the post-transplantation sera was proven by gelfiltration studies, protein A absorption, pepsin-digestion experiments, and incubation with subclass specific monoclonal antibodies; predominantly IgG1 antibodies were found to bind to EC and induce ADCC. The specificity of the antibodies could be shown in panel studies using EC lines of various donors. In order to investigate the clinical relevance and incidence of anti-EC ADCC, we examined whether anti-EC reactivity could be observed in 9 additional renal transplant patients. Sera of 2 of these patients were found positive in the ADCC assay, whereas 20 normal serum donors were negative. ADCC against EC in these patients was not caused by classic antiendothelial-monocyte (EM) antibodies. Using various experimental systems (adherent cell depletion, monoclonal antibody blocking, cold target cell inhibition) it was shown that the natural killer/killer (NK/K) cells present within the peripheral blood mononuclear cell population were responsible for EC lysis. These findings demonstrate that IgG1 antibodies directed against polymorphic non-HLA, non-EM antigens on EC can be induced by renal allotransplantation. Via Fc-receptor interaction with NK/K cells, these antibodies can be responsible for ADCC against EC.

Donor-specific lysis of human kidney proximal tubular epithelial cells by renal allograft-infiltrating lymphocytes

In the present study methods are described to obtain both graft infiltrating cells (GIC) of host origin and proximal tubular epithelial cells (PTEC) of donor origin simultaneously from biopsy material of renal allografts undergoing rejection. The identity of PTEC cultures was established using monoclonal antibodies. GIC were shown to exhibit T cell functional activity. These GIC were shown to lyse trypsinized PTEC as well as PTEC monolayers grown from the corresponding biopsy, and not PTEC isolated from biopsies obtained from other patients. Therefore the lytic activity appeared to be donor-specific. Major histocompatibility complex class I antigens were involved since donor PHA-blasts, a target population well known to express class I molecules, were lysed by GIC, and the anti-class I MoAb W6/32 blocked cytolytic activity of GIC against donor PHA-blasts and against donor PTEC. We thus established that donor-specific lysis of a defined population of kidney epithelial cells, namely PTEC, may occur. This model system, in which GIC and PTEC can be propagated from one biopsy specimen may be useful for further study of cell-cell interactions involved in allograft rejection.

Short-term lymphokine stimulation of human peripheral blood mononuclear cells generates cytolytic activity against endothelial cells: involvement of natural killer cells

We previously reported that incubation of human peripheral blood mononuclear cells (PBMC) for 5 days with T-cell growth factor (TCGF) resulted in lymphokine-activated killer activity against endothelial cells (EC). In this paper we report on the effects of short-term incubation of PBMC with lymphokines. We show that incubation of PBMC with lymphokines during an 18-hr period is sufficient to generate a strong cytolytic response against EC. The cytolytic capacity of the effector cells was directly dependent on the dose of lymphokine added during the induction phase. When PBMC were separated into adherent and non-adherent cells, the non-adherent fraction could be induced to lytic activity against EC, whereas the adherent cells could not. When PBMC were separated, using 2-amino-ethylisothiouronium bromide hydrobromide-treated sheep red blood cells (AET-SRBC), into T- and non-T-cell fractions, the latter fraction could be induced to lyse EC. TCGF-induced cell-mediated EC lysis could not be inhibited using anti-T3 nor anti-LFA-1 antibodies. Lysis of EC by TCGF-stimulated effector cells was strongly inhibited by the addition of unlabelled K562 target cells, whereas cold OKT3 hybridoma cells did not exert such an effect.

IN CONCLUSION

the kinetics of the induction of lytic activity against EC, as well as the cell separation experiments, suggest that short-term-activated NK cells may lyse EC. This hypothesis was confirmed using monoclonal antibody and cold target cell analysis.

The complement subcomponent C1q mediates binding of immune complexes and aggregates to endothelial cells in vitro

The present studies were initiated to investigate whether soluble immune complexes, upon interaction with complement, can bind to endothelial cells. Human umbilical vein endothelial cells (HUVE) were incubated with purified human 125I-labeled C1q at 4 degrees C in RPMI-0.5% bovine serum albumin and assayed for binding. Optimal binding of 125I-labeled C1q to HUVE was reached within 2 h, and saturation of binding was found at concentrations of 5 micrograms/well input. The binding of 125I-labeled C1q was inhibitable with unlabeled C1q and by the collagenous region of pepsin-cleaved C1q. No inhibition was observed with the globular heads of C1q, suggesting that C1q binds to HUVE via the collagenous region of C1q. When HUVE were first reacted with various concentrations of C1q, washed and subsequently incubated with 125I-labeled aggregated human IgM (AIgM), binding of 125I-labeled AIgM to HUVE occurred depending on the dose of C1q. Only those aggregates of IgM which react with C1q in a solid-phase C1q binding assay were able to bind to HUVE presensitized with C1q. In addition it was shown that C1q mediated binding of aggregated IgG to HUVE. Furthermore, immune complexes (IC), that were prepared with bovine thyroglobulin (BTg) and rabbit anti-BTg, bound to C1q-preincubated HUVE. These studies suggest that localization of IC on endothelium can be enhanced following interaction of the IC with complement.

Lymphokine-activated killer cells lyse human renal cancer cell lines and cultured normal kidney cells

In this study, we investigated whether or not lymphokine-activated killer (LAK) cells can damage renal tissue and therefore whether they may contribute to graft destruction during kidney allograft rejection. Human peripheral blood mononuclear cells were activated with a lymphokine preparation and the resulting LAK cells were tested against kidney cells from various sources. Renal cancer cells as well as cultured normal kidney cells were efficiently lysed by LAK cells, as assessed with Cr-labelled target cells, showing that both cell types are sensitive to LAK cell-mediated cytolysis.