An arthritogenic lymphokine in the rat

Collagen antibody induced arthritis

Rheumatoid arthritis (RA) is a polygenic and multifactorial disease. Many complex immunological and genetic interactions are involved in the final out come of the clinical disease. To understand the various disease pathways operating during the disease course, we need many different animal models. Collagen induced arthritis (CIA) is one of the widely used animal models sharing many pathological and histological similarities with RA and antibodies play an important role in the inflammatory phase of CIA. This chapter describes, in detail, an animal model for arthritis using CII specific monoclonal antibodies, the so-called collagen antibody induced arthritis (CAIA), which shares many characteristics of CIA. CAIA model provides an opportunity to study the inflammatory phase of arthritis without involving the priming phase of the immune response. CAIA can be used for not only studying inflammatory processes in arthritis and screening drug candidates controlling joint inflammatory phase but also as a model for studying common mechanisms involved in many antibody mediated diseases.

Inhibition of type II collagen-induced arthritis in rats by triptolide

The effects of purified triptolide, a diterpenoid triepoxide compound derived from the Chinese traditional anti-rheumatic medicinal plant extract, Tripterygium wilfordii Hook f (TWHf), were determined in type II collagen-induced arthritis (CIA) in rats. Lewis rats were immunized with bovine type II collagen and treated with purified triptolide 0.1 mg/kg/day or control (vehicle for triptolide) by daily gavage feedings for 28 days. Triptolide was well-tolerated with no evidence of toxicity. Treatment with triptolide resulted in significant delay in time to onset of arthritis (P = 0.039), as well as significantly decreased arthritis incidence (P = 0.024), clinical arthritis severity score (P < 0.0001), histopathological arthritis severity score (P < 0.0001), and in vivo cell-mediated immunity to collagen (P = 0.0004). Triptolide appeared to be a potent immunomodulatory inhibitor of CIA in rats and this may account for the previously observed anti-rheumatic properties of crude extracts of TWHf, although more extensive studies will be needed to confirm these effects.

Effects of oral administration of type II collagen on rheumatoid arthritis

Rheumatoid arthritis is an inflammatory synovial disease thought to involve T cells reacting to an antigen within the joint. Type II collagen is the major protein in articular cartilage and is a potential autoantigen in this disease. Oral tolerization to autoantigens suppresses animal models of T cell-mediated autoimmune disease, including two models of rheumatoid arthritis. In this randomized, double-blind trial involving 60 patients with severe, active rheumatoid arthritis, a decrease in the number of swollen joints and tender joints occurred in subjects fed chicken type II collagen for 3 months but not in those that received a placebo. Four patients in the collagen group had complete remission of the disease. No side effects were evident. These data demonstrate clinical efficacy of an oral tolerization approach for rheumatoid arthritis.

Defective signal transduction via T-cell receptor-CD3 structure in T cells from rheumatoid arthritis patients

T cells from patients with active RA are known to produce low levels of IL-2 and proliferate poorly in response to various mitogenic stimuli. The present work shows that cross-linking of CD3 antigen on patients' T-cell surface induces two- to threefold lower Ca2+ response than in T cells from age-matched controls. Immunofluorescence studies indicate that the attenuated signal may be due to the suppressed expression of CD3 and/or CD45 molecules on patients' T cells. In the majority of the patients, the level of CD45 expression is reduced by 60%-70% as compared with that in the control T cells. Therefore, the poor mitogenic response of patient cells is apparently due to a defect in early stages of signal transduction through the T-cell receptor (TCR-CD3).

Antigen-activated T cells inhibit cartilage proteoglycan synthesis independently of T-cell proliferation

Previously we have shown that blood mononuclear cells (MNC) obtained from patients with rheumatoid arthritis (RA) have the capacity to induce depletion of proteoglycans (PG) in human cartilage explants. This was observed especially after stimulating MNC with mycobacterial antigens, rather than with the mitogen Concanavalin A (Con A). We have now co-cultured cartilage explants in the presence of T-cell clone A2b obtained from the rat model of adjuvant arthritis (AA). We show that inhibition of the cartilage PG synthesis is a consequence of antigen-specific T-cell activation and that it is mediated by a humoral factor. This seems to be a cytokine rather than an enzyme. Moreover, at the level of polyclonally responding T cells, inhibition of PG synthesis due to T-cell activation by mycobacterial antigens was shown to depend on prior mycobacterial immunization. Arthritogenic T-cell clone A2b also showed PG synthesis inhibitory effects when co-cultured with cartilage alone. The inhibitory activity was shown to be unrelated to the degree of T-cell proliferation. We conclude that antigen-specific T-cell activation may be one of the initiating events leading to cartilage damage in arthritic processes. The measurement of T-cell-mediated PG synthesis inhibition may be a more sensitive and relevant assay for the detection of pathogenic T cells than T-cell proliferation.

Suppression of collagen arthritis with antibodies to an arthritogenic, oligoclonal T cell line

Rats immunized with type II collagen (CII) develop an immunologically mediated polyarthritis. T cells have been implicated in the pathogenesis of this model since they can adoptively transfer the disease. A CII-specific T cell line (VA), consisting of three distinct clones by Southern blot analysis, has been shown to be arthritogenic. Antibodies specific for this line were generated by immunizing rabbits. In an attempt to prevent collagen-induced arthritis (CIA), Louvain rats were injected with 1 ml of anti-VA ip on Days -1, +1, +3 and 0.5 ml on Day +5 (early treatment). To evaluate its effect on existing disease, rats received anti-VA on the day of arthritis onset and subsequently on 4 successive alternate days using the same dosage protocol (late treatment). Control rats received no therapeutic injections or were administered normal rabbit serum. All rats were immunized with CII on Day 0 to induce CIA. Rats administered antibodies using the early anti-VA treatment protocol had a significantly diminished incidence of arthritis compared to controls. Established arthritis was significantly diminished compared to controls in rats given the late anti-VA treatment. In both protocols, radiographic evidence of joint destruction was significantly reduced compared to controls. T cell phenotyping using flow cytometry analysis demonstrated that the anti-VA antibody therapy selectively eliminated a small subset of T cells since there was little difference in total T cell counts in the experimental versus control groups. Delayed type hypersensitivity and IgG antibody titers to CII were minimally decreased in the experimental versus control group. These results suggest that antibodies raised to an oligoclonal arthritogenic T cell line can suppress collagen arthritis. This may have implications with respect to 1) the size of the T cell receptor repertoire involved in the pathogenesis of collagen arthritis and 2) immunospecific protocols for CIA and other autoimmune diseases.

Flare-up of experimental arthritis in mice with murine recombinant IL-1

Intra-articular injections of murine recombinant IL-1 (mrIL-1) during the chronic phase of antigen-induced arthritis (AIA) induced a flare-up of the smouldering inflammation. The exacerbation was characterized by acute and transient joint swelling and this coincided with the extravascular accumulation of neutrophils. IL-1 injected into arthritic joints of neutropenic mice demonstrated that joint swelling was independent of the neutrophil influx into the joint. Both phenomena were absent when IL-1 was injected into a naive joint. The IL-1-induced flare-up was not T cell mediated as in the antigen-induced flare-up, and suggestive evidence is presented that IL-1 sensitivity depended on the resident macrophage population. This explained why the hypersensitivity is not restricted to the immunologically mediated arthritis but reflects a more general hypersensitivity of previously injured joints, e.g. zymosan-induced arthritis and IL-1-affected joints. In addition, IL-1 could also potentiate the antigen-specific flare-up of chronic AIA and prolongs the duration of the exacerbation. Our data indicate that joints bearing a chronic infiltrate are at risk from exacerbations in two ways: a T cell mediated rechallenge with antigen, and a non-specific reactivation by systemic and local IL-1 generation.

Intractable vasculitis, resorptive osteolysis, and immunity to type I collagen in type VIII Ehlers-Danlos syndrome

A unique patient with type VIII Ehlers-Danlos syndrome and cutaneous vasculitis, resorptive osteolysis, and cardiac valvular disease is described. Collagen analyses identified morphologic and physical abnormalities of type I collagen. The patient's T lymphocytes could be propagated in vitro with type I collagen and produced a 60-kd lymphokine that bound this protein. Cellular autoimmunity to type I collagen may be responsible for this patient's intractable clinical condition.

T cell derived proteins from normal human sera and their relationship to T cell antigen binding molecules

We have used procedures which have been developed to isolate murine T cell antigen binding molecules (TABM) in order to isolate TABM from normal human sera. To begin purification, ammonium sulfate (NH4)2SO4 was added to human serum and precipitated protein was dissolved in low salt buffer and resolved by ion-exchange chromatography on carboxymethylcellulose (CM). The most strongly CM nonadherent fraction was absorbed with anti-human albumin and anti-human immunoglobulin (Ig) antibodies conjugated to Sepharose beads. The resulting nonadsorbed 110,000, 70,000 and 45,000 Mr polypeptides were reactive in ELISA with a rabbit antiserum produced against non-Ig, anti-specific molecules of rhesus monkeys. These proteins possess alpha mobility upon immunoelectrophoresis and represent 0.02 to 0.05% of total serum protein. In addition, these proteins are bound by an antiserum made against a synthetic peptide corresponding to the J region of the TcR beta chain. We have made R28, a rabbit antiserum against these serum proteins which binds specifically to tetanus-specific polypeptides obtained from the culture supernatant of human T cell lines specific for tetanus. This antiserum also binds to proteins isolated from T cell but not B cell lines, and T cell proteins are able to inhibit the binding of R28 to the human serum polypeptides. The results suggest that the proteins isolated from normal human sera are T cell antigen binding molecules.

Influence of muramyl dipeptide on established experimental arthritis in rats

The effects of MDP, a potent inducer of cytokines, were studied in four batches of Wistar Furth rats with established experimental arthritis. Arthritic rats were given a daily sc injection of 10, 100, 200 or 400 micrograms MDP respectively. Muramyl dipeptide increased the severity of clinical events in a dose-dependent manner, with the exception of the 10 micrograms dose which was ineffective. The levels of anti-collagen antibodies were not however significantly enhanced by MDP. Radiological lesions and histological changes were maximal at high dosage regimens. Paradoxically, the acute phase reactive alpha 1 glycoprotein was little affected by MDP treatment.

Characterization of collagen-specific T cells derived from pathogenic and nonpathogenic rat T cell lines

Rat/mouse T-T hybridomas have been developed from an arthritogenic and a nonarthritogenic T cell line. These hybridomas express alpha beta TCR and are CD4+, CD8-, and MRC OX-22-. They have type II collagen reactivity as assessed by an IL-2 release assay. Southern blot analysis of DNA extracted from these hybridomas demonstrates that each T cell line contains at least three different collagen-reactive clones. The data suggest that the spectrum of TCR beta gene rearrangements is limited, as one hybridoma from the nonpathogenic line shares an identically sized productive TCR beta gene rearrangement with two hybridomas from the pathogenic line. Both cell lines as well as one hybridoma from the pathogenic line are autoreactive to rat type II collagen. The anti-collagen responses of all the hybridomas are restricted to the rat class II MHC RT1.B gene loci. The hybridomas, like their parental cell lines, do not respond preferentially to either native or denatured type II collagen. These hybridomas recognize a specific type II collagen epitope and not repetitive collagen-like sequence motifs. They require antigen processing to respond to both native and denatured type II collagen.

Activation pathways of synovial T lymphocytes. Expression and function of the UM4D4/CDw60 antigen

Accumulating evidence implicates a central role for synovial T cells in the pathogenesis of rheumatoid arthritis, but the activation pathways that drive proliferation and effector function of these cells are not known. We have recently generated a novel monoclonal antibody against a rheumatoid synovial T cell line that recognizes an antigen termed UM4D4 (CDw60). This antigen is expressed on a minority of peripheral blood T cells, and represents the surface component of a distinct pathway of human T cell activation. The current studies were performed to examine the expression and function of UM4D4 on T cells obtained from synovial fluid and synovial membranes of patients with rheumatoid arthritis and other forms of inflammatory joint disease. The UM4D4 antigen is expressed at high surface density on about three-fourths of synovial fluid T cells and on a small subset of synovial fluid natural killer cells; in synovial tissue it is present on more than 90% of T cells in lymphoid aggregates, and on approximately 50% of T cells in stromal infiltrates In addition, UM4D4 is expressed in synovial tissue on a previously undescribed population of HLA-DR/DP-negative non-T cells with a dendritic morphology. Anti-UM4D4 was co-mitogenic for both RA and non-RA synovial fluid mononuclear cells, and induced IL-2 receptor expression. The UM4D4/CDw60 antigen may represent a functional activation pathway for synovial compartment T cells, which could play an important role in the pathogenesis of inflammatory arthritis.

Immunotherapy of collagen-induced arthritis by a T-cell antiproliferative molecule

The present study describes a novel experimental immunotherapeutic methodology for the reduction of inflammatory synovitis that is noted in an animal model of rheumatoid arthritis. The reduction in inflammation is noted in the animals administered a contra-interleukin-2 (IL-2) cytokine secreted by a cloned T-cell line. The mechanism of reduction of inflammation by this cytokine is through the inhibition of activation and differentiation of T lymphocytes. The cytokine inhibits the in vitro mitogen activation of T-cell lymphocytes as well as antigen-specific activation of a collagen type II specific T-cell line. In addition, decreased levels of messenger RNA coding for interleukin-2 are noted in T lymphocytes and IL-2 activation of the collagen type II specific cell line is inhibited by the contra-IL-2 cytokine. This initial description of a reduction in inflammation by a contra-IL-2 lymphokine suggests that immunoregulatory biologic molecules that are antagonists to IL-2 may be useful for the experimental immunotherapy of cartilage connective tissue pathology.

Regression of bone and cartilage loss in adjuvant arthritic rats after treatment with cyclosporin A

To test the effect of cyclosporin A (CsA) on arthritis-related bone resorption, we studied 30 female rats with adjuvant-induced arthritis (AIA). The animals were randomly assigned to 5 groups of 6 animals each; they received daily oral doses of 3, 5, 10, or 15 mg/kg CsA or placebo for 10 days. The parameters studied were (a) caliper measurements of hindpaw swelling, (b) radiometric densitometry of caudal vertebrae, (c) quantitative histomorphometry of radiographed vertebrae, and (d) glycosaminoglycan measurements in femoral condyles. A significant dose-dependent regression of articular swelling occurred in rats given 5, 10, and 15 mg/kg CsA, and this was concomitant with improvement in bone density. These results correlated with those of quantitative bone morphometry. Thus, trabecular volume was significantly reduced in AIA rats, but restoration to virtually normal values occurred with CsA doses between 5 and 15 mg/kg. The protective effect of CsA on articular damage was supported by the dose-dependent progressive improvement in total femoral condyle glycosaminoglycan content. The favorable effect of CsA on AIA is likely due to a blockade of T cell activation via an inhibition of production of lymphokines such as interleukin-2 and gamma-interferon. The consequent cessation of the immune reaction would lead to a reduction in the release of cytokines, such as interleukin-1, that are likely to be the mediators of the pathologic bone and cartilage breakdown that is characteristic of arthritic disease.

A contra-IL-2 cytokine derived from mice suppressed for collagen-induced arthritis

The present study identifies and characterizes a cytokine derived from a T cell hybridoma which inhibits interleukin-2 (IL-2) function. The T cell hybridoma, T101N, was derived from somatic cell hybridization of lymphoid cells from mice suppressed for collagen-induced arthritis. Serial dilution of T101N cell culture medium reveals a concentration-dependent inhibition of recombinant IL-2 induced proliferation. Physiochemical properties of the inhibitor indicate that the contra-IL-2 activity is optimally resolved at 37 degrees C and neutral pH. Analysis of the molecular characteristics of the contra-IL-2 activity indicate that the cytokine activity is most biologically active as a pentimeric molecule of high molecular weight. Apparent molecular weight of monomeric contra-IL-2 is approximately 30,000-35,000 Da.

Expression of non-MHC-restricted T cell antigen-binding molecules by thymic lymphocytes

Heterologous antisera which recognize non-major histocompatibility complex (MHC)-restricted T cell antigen-binding molecules (TABM) were used to characterize the expression and structure of TABM on thymic lymphocytes. Approximately 70% of thymocytes express membrane molecules bound by anti-TABM antibodies (mTABM). Antibody activity for thymocyte TABM could be removed by adsorption to splenic T cells, but not by adsorption to splenic B cells. Similarly, adsorption of the antiserum to thymocytes or splenic T cells removed antibody activity to a purified TABM whereas adsorption with B cells had no effect. Radioiodinated thymic and splenic T cell mTABM were resolved by 2D-polyacrylamide gel electrophoresis and when reduced, both populations of mTABM migrated primarily as Mr 23,000 proteins with an isoelectric point range of 6.8-7.8. Multimers of this protein were also observed at Mr 85-97,000 and 130-150,000 on both thymocytes and splenic T cells. These data indicate that MHC-unrestricted antigen-binding molecules are expressed by a majority of thymocytes and these thymic TABM are structurally and antigenically similar to mTABM on peripheral cells. This suggests an ontogenic relationship between thymic TABM and peripheral TABM.

Clonal heterogeneity of synovial fluid T lymphocytes from patients with rheumatoid arthritis

Although substantial evidence suggests that synovial T lymphocytes are critical in the pathogenesis of rheumatoid arthritis (RA), little is known regarding their antigenic specificities, antigen receptor gene rearrangements, and mechanisms of activation. To assess the extent of expansion of specific clones among RA synovial fluid T cells, Southern blot analyses of T-cell receptor (TCR) gene rearrangements were performed on 40 RA synovial fluid T-cell clones, as well as on both fresh and polyclonally activated T cells from RA synovial fluid, RA peripheral blood, and normal peripheral blood. Two of the clones had identical TCR rearrangement patterns, but the remainder were unique. The nonclonal RA T-cell samples showed the same pattern of TCR beta-chain rearrangement that was observed among normal peripheral blood T cells, indicating no dominant clonal T-cell population in these samples. It was noted that with sufficient exposure of autoradiograms of the Southern blots, discrete TCR gene rearrangements, representing in some cases common D beta J beta (D, diversity; J, joining) rearrangements, were evident in T cells from peripheral blood of normal individuals and patients with RA, as well as T cells from RA synovial fluid. Taken together, the findings indicate that only a minor degree of oligoclonality can be demonstrated among T lymphocytes from RA synovial fluid.

Collagen induced arthritis as an experimental model for rheumatoid arthritis. Immunogenetics, pathogenesis and autoimmunity

The type II collagen (CII) induced arthritis animal model (CIA) provides opportunities to study the nature of autoimmune reactions leading to arthritis and may be used as a model for rheumatoid arthritis (RA). Thus, in similarity with RA, the CIA model, when induced with autologous CII, shows a chronic and progressive disease course. The susceptibility to both RA and CIA are correlated to the expression of certain MHC class II allotype genes. In both diseases are autoantibodies to CII and rheumatoid factors produced. Immunohistopathology of affected joints show in both diseases a dominance of activated macrophages/fibroblasts with a significant infiltration of activated T cells and an infiltration of granulocytes. We do here suggest that both RA and CIA are dependent on a synergy between delayed type hypersensitivity and immune complex mediated inflammatory mechanisms and that CIA provides opportunities for studies of immunospecific reactions leading to arthritis.

Collagen arthritis in the rat is initiated by CD4+ T cells and can be amplified by iron

The role of iron in arthritis was studied by administering ferric citrate (Fe-cit) to age-matched, female Sprague-Dawley rats immunized with chick type II collagen on Day 0. Rats received intravenously (iv) either Fe-cit (7.7 mg/kg body wt) or an identical concentration of sodium citrate on varying days after immunization. Transferrin saturation peaked (88-95%) 1 hr post-Fe-cit and returned to baseline values within 24 hr. Injection of Fe-cit on either Day 3 or Day 5, but not on Day 7 or Day 9, significantly (P less than 0.03) increased the incidence of arthritis. Synovium from the infrapatellar fat pad was harvested on Days 0-10 for analysis by immunocytochemistry. The inceptual morphologic change in the synovium following collagen immunization in rats not injected iv was an increase in the number of CD4+ and transferrin receptor+ mononuclear cells in perivascular regions; compared to Day 0 both cell types had increased two- to threefold by Day 3. On Day 7, an increase in CD8+ mononuclear cells occurred and the first polymorphonuclear leukocytes were noted. These alterations resulted in a peak in the CD4-CD8 ratio on Day 3, with a gradual decline thereafter. Although Fe-cit administration promoted the ingress of these mononuclear cells, it did not change the CD4-CD8 ratio significantly or recruit polymorphonuclear leukocytes into the joint tissue. Serum antibody titers to type II collagen, measured 20 days after immunization by an enzyme-linked immunosorbent assay, and delayed-type hypersensitivity to collagen, measured by a radiometric ear assay on Day 23, did not differ significantly between the groups. As well as showing that the initial intrasynovial event in collagen arthritis is perivascular infiltration by members of the CD4+ T cell subset displaying a phenotypic sign of activation, these findings demonstrate that iron administered at a critical time after immunization enhances the induction of collagen arthritis. The coincidence of this brief period of susceptibility with maximum CD4-CD8 ratios within the synovium and its occurrence prior to the stage of neutrophil infiltration are consistent with the possibility that the augmenting effect of iron is mediated by the inducer T cell subset.

Enhanced production of interleukin-6 in mice with type II collagen-induced arthritis

We established an interleukin-6 (IL-6)-dependent cell line from murine plasmacytoma MOPC-104E cells. This cell line (designated PIL-6) was found to respond to murine and to human IL-6, but not to any other cytokines. We used this cell line to investigate the involvement of IL-6 production in type II collagen-induced arthritis in DBA/1 mice. Only marginal IL-6 activity was detected in sera from DBA/1 mice inoculated with Freund's complete adjuvant (FCA) alone, with an unrelated protein (bovine serum albumin) plus FCA, or with type II collagen plus Freund's incomplete adjuvant. However, enhanced IL-6 activity was observed in DBA/1 mice that had been injected with type II collagen plus FCA to induce arthritis. The elevated level of serum IL-6 activity was associated with high levels of IL-6 produced when lymph node cells from arthritic mice were stimulated in vitro with type II collagen. We also found that the L3T4+ T cell subset is responsible for the enhanced production of IL-6 in arthritic mice. The results are discussed in the context of potential roles of IL-6 in the induction and/or expression of chronic, progressive arthritis.

Experimental synovitis induced by collagen-specific T cell lines

Type II collagen (CII) and ovalbumin (OV) reactive T cell lines were developed from the lymph node cells of Louvain rats previously immunized with the respective antigen. Histologic sections of rat knees injected intraarticularly (ia) with 10(6) cells from line CII (VA) or CII (VII) were graded blindly. Significant synovitis (P less than 0.000001 and 0.004, respectively) was evident compared to OV line recipients. Pannus developed within 48 hr, persisted for at least 4 to 6 weeks, was inducible with fewer than 10(3) CII cells, and required viable lymphocytes. The process was independent of anticollagen antibodies and was associated with the lines' capacity to elaborate a previously described 65-kDa CII-binding arthritogenic lymphokine. Line CII (VIII), which could not elicit a synovitis, did not produce detectable quantities of this factor. A line- and antigen-specific synovitis, comparable to the ia injection protocol, was also induced by intravenous administration of 2 x 10(7) CII (VA) cells and ia challenge with soluble collagen. These studies demonstrate that CII lines bearing the T helper phenotype can evoke a sustained synovitis and suggest that this experimental process is associated with the release of an arthritogenic lymphokine and not dependent on the formation of antibodies to CII.

Immunophenotypic analysis of the inflammatory infiltrate in ocular cicatricial pemphigoid. Further evidence for a T cell-mediated disease

Ocular cicatricial pemphigoid (OCP) is characterized by the deposition of immunoglobulin and complement along the conjunctival epithelial basement membrane zone (BMZ). In order to further elucidate the cellular populations of the local inflammatory infiltrates, the authors used a panel of monoclonal antibodies in cryostat tissue sections to delineate T cell subsets, B lymphocytes, dendritic cells, and macrophages in six patients with OCP. In comparison with matched controls of the epibulbar conjunctiva, the authors discovered a threefold increase in T lymphocytes within the epithelium and a 20-fold increase within the substantia propria. In contrast with the normal-standing population of conjunctival T lymphocytes, there were activated interleukin 2 receptor (IL-2R)-positive lymphocytes in both the epithelium and the substantia propria. Macrophages were the second most common cells in the substantia propria, accounting for 12.7% of the mononuclear population--a threefold increase over the normal percentage. B cells and plasma cells, normally absent from epibulbar conjunctiva, were the next most prominent populations, constituting 6.9 and 4.6%, respectively, of all mononuclear cells. Dendritic cells which process antigen locally constituted only 1.2% of the mononuclear cell population, but were increased 25-fold over normal controls. By elaborating cytokines that promote fibroplasia, the T cells in OCP may be effector cells along with macrophages and other inflammatory cells in bringing about scarification of the substantia propria, and may furthermore be responsible for an immunoregulatory defect that allows local B lymphocytes to produce autoantibodies to the BMZ.

Induction of erosive arthritis in mice after passive transfer of anti-type II collagen antibodies

The passive transfer of concentrated immunoglobulins or affinity-purified anti-collagen antibodies from sera of mice with type II collagen-induced arthritis can induce erosive arthritis in recipient animals. In both cases, the incidence of arthritis was over 60% and the inflammation persisted for at least two weeks. Radiography revealed bone destruction and apposition of a newly formed material while histologic examination showed cartilage and bone degradation, accompanied with synovitis and periarthritis. Inflammatory infiltrates were composed of polymorphonuclear leucocytes and lymphocytes, and were associated with a proliferation of connective tissue cells.

Lymphokine regulation of inflammatory processes: interleukin-4 stimulates fibroblast proliferation

While recent evidence from several laboratories has shown that interleukin-4 (IL-4) can act on a number of cells in addition to B lymphocytes, these have thus far been limited to cells of the hematopoietic lineage. Here we report that murine IL-4 promotes DNA synthesis in both primary and immortalized fibroblasts. Marked stimulation of [3H]thymidine incorporation was observed for primary skin fibroblasts or Balb/c3T3 cells stimulated with HPLC- or immunoaffinity-purified as well as recombinant IL-4. Responses to immunoaffinity and recombinant IL-4 were completely blocked with anti-IL-4 antibody. Similar dose/response relationships were observed for recombinant IL-4 on skin fibroblasts and an IL-4 responsive murine T cell tumor, suggesting that the receptors for this lymphokine on these cells is similar. Together, these results show that IL-4 can cause DNA synthesis by murine fibroblasts presumably through ligand-receptor interactions at the cell surface. Implications of these findings to inflammation during an immune response is discussed.

Treatment with gamma-interferon triggers the onset of collagen arthritis in mice

We investigated the effect of gamma-interferon (gamma-IFN) on the development of type II collagen (CII)-induced arthritis. DBA/1 mice were immunized with rat CII and 16 days later, were treated with subcutaneous injections of recombinant rat gamma-IFN into the right paws twice a week. Compared with controls, the gamma-IFN-treated mice developed arthritis with a higher frequency and severity. Immunohistochemical analysis of gamma-IFN-treated paws from CII-immunized mice revealed an increase in the numbers of class II antigen-expressing cells and an infiltration of CD4+ lymphocyte-like cells. The auto-antibody response toward CII was suppressed by gamma-IFN treatment. The findings implicate gamma-IFN in a role that triggers arthritis by enhancing local inflammatory processes in the joints, or possibly, by permitting homing of T cells to the joints.

In vivo modulation of murine collagen induced arthritis

The effects of in vivo modulation of murine collagen induced arthritis with monoclonal anti-CD4 antibodies, monoclonal anti-Ia antibodies, and gamma interferon are reviewed. We detail the mechanism of action of monoclonal anti-CD4 antibody on humoral and cell mediated immune responses and discuss the implications for designing therapeutic strategies. To further explore the induction of collagen induced arthritis, a syngeneic cell transfer system using collagen primed T lymphocytes is described. This cell transfer system provides an opportunity to study the role of CD4 positive T lymphocytes in arthritis induction during a short, defined time period.

Passive collagen arthritis induced by anticollagen IgG

Studies conducted in rats and mice indicate that passive arthritis can be transferred to naive recipients with anticollagen IgG. The passively transferred disease is less severe and is transient. Rats that recover from passive arthritis are resistant to a second phase of clinical disease when administered either anticollagen IgG or type II collagen. Suppressor T cells appear to be responsible for this resistance. Passive arthritis induced by anticollagen IgG is a complement dependent lesion. Deposition of IgG on the cartilage and host complement C3 and C5 activation are essential for the induction of passive disease. Inflammatory cells are necessary for the demonstration of passive arthritis; mice deficient in inflammatory cells or defective in this cell population are resistant to passive arthritis. Monoclonal antibodies reactive to type II collagen or to a renatured TCA fragment can also induce passive arthritis. The disease is subclinical and can be detected only after histological analysis of the joints.

Collagen arthritis in rats, arthritogenic lymphokines and other aspects

This review will mainly highlight data from selected, independent studies which collectively implicate a primary role for T cells in the pathogenesis of collagen arthritis in rats. Conferring insusceptibility to this experimental disease with the use of polyclonal, T cell specific antiserum provided direct initial evidence for this conclusion. Substantiation for the theory of a dominant T cell role in collagen arthritis was afforded by T cell line vaccination; scrutiny showed that the mechanism accounting for this protection was a specific down-regulation of the cellular response to collagen. Additional support came from experiments which showed that as few as 10(3) type II collagen specific T line cells were capable of provoking a sustained proliferative synovitis when instilled into the knee joint cavity of syngeneic naive rats. Further analysis of this phenomenon revealed that the arthritogenic capacity of various collagen-reactive line cells correlated with their ability to release a 65-Kd, collagen-binding lymphokine. This antigen-specific lymphokine was designated arthritogenic factor, based on an arthritogenic activity in the knee joint bioassay similar to that of the cells. A functional and physicochemically identical rat arthritogenic factor has also been identified in the adjuvant model of arthritis. These data support the premise that a major effector mechanism in experimental rat arthritis is the release of arthritogenic factor by expanded clones of autoreactive T cells; they also indicate that substantive efforts should be undertaken to seek to identify arthritogenic factor-like lymphokines in patients with chronic inflammatory synovial disease. As an equally plausible alternative hypothesis, the review will close with a brief discussion of recent findings supporting the possible involvement of cartilage-binding, complement-fixing anti-type II collagen antibodies in the pathogenesis of rheumatoid arthritis.

Antigen specific down regulation of murine collagen induced arthritis: T suppressor cell circuits in arthritis immunotherapy

The present article summarizes a series of experiments which have been performed to describe an antigen-specific suppressor cell pathway for the suppression of the erythema and edema associated with an animal model of rheumatoid arthritis, collagen induced arthritis (CIA). Initial studies utilized the adoptive transfer of splenic cell subpopulations to establish the presence of suppressor cells in lymphoid tissues of mice which were suppressed for collagen induced arthritis. Subsequent studies generated T cell hybridomas from animals which had been suppressed for collagen induced arthritis by a single injection of a large quantity of Type II collagen. The T cell hybridomas varied in their self surface expression of glycoproteins which are associated with genetically determined functions. The suppressor T cells generated, described a regulatory suppressor cell pathway comprised of at least afferent suppressor T cells and effector suppressor T cells. The cells act in an antigen-specific fashion with regard to the suppression of collagen induced arthritis but appear to be polymorphic in their recognition of the interstitial collagens. The studies, taken together, indicate that the use of antigen specific T suppressor cells in the form of T cell hybridomas can be utilized as a form of immunotherapy in experimental arthritis.

Experimental autoimmune arthritis in mice. II. Early events in the elicitation of the autoimmune phenomenon induced by homologous type II collagen

Intradermal injection of 100 micrograms of native homologous type II collagen (CII) into DBA/1-susceptible mice induced a progressive and chronic polyarthritis. This experimental autoimmune arthritis (EAA) closely mimicked the clinical evolution of human rheumatoid arthritis (RA) except for the sex linkage. Males were highly susceptible to EAA induction even when the amount of autoantigen injected was reduced to 25 micrograms. Conversely, females remained resistant to the disease even when a booster injection of 50 micrograms was administered. With regard to age, no major difference in the incidence was observed, although younger males developed a more severe arthritis than older ones. Anti-CII autoantibodies were detected in all immunized animals, regardless of the presence or absence of joint pathology. However, in arthritic mice, the onset of the disease was associated with a predominance of IgG2a autoantibodies. Kinetic studies revealed that females as well as males exhibited early histological lesions and detectable humoral responses toward mouse CII as of the second week postimmunization. Moreover, a specific cellular autoreactivity to homologous CII occurred in different lymphoid organs with a higher intensity in females than in males. Taken together, these findings suggest that homologous CII injection induces an early subclinical arthritis that develops progressively in all immunized mice, but would be down-regulated several weeks after priming, exclusively in females.

Activation of rat synovium by iron

We observed a consistent sequence of activation changes in rat knee synovia following a single intravenous injection of sterile ferric citrate at a dosage sufficient to cause a transient saturation of transferrin. The initial alteration, appreciated 2 hours postinjection, consisted of an expansion in the lumen of synovial lining and subsynovial tissue due to the hypervascularity and increased cellularity was noted, along with peaks in the mitotic activity of synovial cells (fourfold over baseline) and pinocytosis by endothelial cells. During the period of 8-24 hours, mature collagen appeared in the space between pericyte layers and between pericytes and endothelial cells, and 2-9-fold increases in ferritin +, W3/13+, W3/25+, Ox8+, and Ox26+ mononuclear cells occurred. In contrast to the action on synovial fibroblasts, iron injection did not affect the mitotic activity of fibroblasts within the serosa of the small intestine. These findings demonstrate that, under experimental conditions, iron can readily induce changes in the synovium that are reminiscent of early events occurring in response to antigen.

Studies on the synergy between collagen and adjuvant arthritis in rats

Intravenous administration of subarthritogenic doses of anticollagen IgG and adjuvant-sensitized spleen cells to syngeneic naive rats induces an erosive arthritis in recipients. The onset of the clinical disease in recipients is rapid and the disease is severe when compared to those recipients receiving cells alone. Immunocytochemical analysis of the knee synovium indicates the accumulation in the adipose tissue of Ia+ (ED1+)macrophages, OX-19+ T lymphocytes, and neutrophils. A large proportion of the lining cells of the proliferative synovium are Ia+. The knee synovium is extremely edematous and contains fibrin. If recipient rats are decomplemented, clinical disease is delayed and the number of mononuclear and polymorphonuclear cells accumulating in the synovium is decreased. Similar results are observed if recipient rats are treated with anti-Ia+ antibody. However, anti-Ia+ treatment does not induce depletion of serum complement.

Tolerogenic activity of polymerized type II collagen in preventing collagen-induced arthritis in rats

Rats were exposed parenterally or pergastrically to polymerized type II collagen (POLCII) and became resistant to the subsequent induction of disease with arthritogenic type II collagen (CII) administered intradermally in Freund's incomplete adjuvant (FIA). POLCII was prepared by cross-linking native soluble arthritogenic CII, from bovine nasal septal cartilage, with glutaraldehyde. POLCII injected intradermally in FIA did not induce arthritis. Animals treated in this manner were resistant for a period of at least 100 days to induced disease. The change in the properties of the CII from an arthritogen to a tolerogen was related to the amount of glutaraldehyde (used to polymerize the CII) which was assumed to control the extent of cross-linking of the CII. Highly cross-linked POLCII administered pergastrically, like soluble CII, was not arthritogenic but was tolerogenic, inducing a state of unresponsiveness to a challenge with arthritogenic CII. In general serum anti-CII antibody levels were higher in arthritic than in tolerized non-arthritic rats. It is concluded that the breaking of self-tolerance to CII depends upon its physical state. When polymerized and insoluble, a form analogous to that in which it exists naturally, it is tolerogenic.

Regulation of in vivo immunological reactions by monoclonal antibody against lymphocyte activation antigen

In vivo effects of a monoclonal antibody that recognizes rat lymphocyte activation antigen were studied. Spleen cells obtained from sheep red blood cell (SRBC)-immunized rats developed strong PFC response against SRBC. However, the 5C6-F4 treatment resulted in the inhibition of subsequent development of PFC response. The suppression of PFC response was due to the inhibition of generation of helper T cells, but not due to the preferential induction of suppressor cells. In addition, 5C6-F4 antibody was also found to inhibit the clinical expression of collagen-induced rat arthritis and the synovial inflammation in collagen-induced arthritis rats. Furthermore, the in vivo generation of cytotoxic cells against syngeneic tumor cells was also inhibited by 5C6-F4 antibody. The in vivo administration of 5C6-F4 antibody did not cause any pathological changes in brain, lung, liver, kidney, spleen, thymus, and lymph nodes.

Partial characterization of a fibroblast-stimulating factor produced by cloned murine T lymphocytes

T cells may regulate tissue fibrosis through the elaboration of soluble factors that stimulate fibroblast growth. The authors previously identified a factor produced by cloned Schistosoma mansoni antigen-specific T cells which served as a competence factor for murine fibroblasts. In the present report, they further characterize this fibroblast-stimulating factor (FsF) and differentiate it from a number of other T-cell-derived lymphokine activities. Crude supernatants from concanavalin-activated cloned T cells were fractionated by gel filtration, ion exchange, or reversed-phase high-pressure liquid chromatography. FsF has an apparent molecular weight of 17,000 and could be differentiated from colony-stimulating factor (CSF), interleukin-3 (IL-3), and interferon (IFN) on the basis of chromatographic characteristics. Highly purified or recombinant IL-2, IL-3, CSF, and IFN had no significant effect on fibroblast proliferation. Furthermore, a monoclonal anti-B-cell-stimulating factor-1 antibody only partially blocked the fibroblast proliferation induced by T-cell supernatants.

Oestrogen-induced suppression of collagen arthritis. II. Treatment of rats suppresses development of arthritis but does not affect the anti-type II collagen humoral response

Immunization of female Lewis rats with bovine type II collagen induces a severe polyarthritis with an incomplete penetration. Castration of the rats increased the incidence to 94% compared with 50% among sham-operated controls. When castrated female rats were implanted with silicone capsules containing beta-oestradiol they developed arthritis with a delayed onset and a decreased severity compared with castrated rats implanted with empty Silastic capsules. The levels of anti-type II collagen auto-antibodies were not affected by castration or oestrogen treatment. These findings show that oestrogen suppresses the development of collagen arthritis in rats and that this effect is mediated by mechanisms other than anti-type II collagen auto-antibodies.

Immunotherapy of experimental arthritis. Analysis of the articular cartilage of mice suppressed for collagen-induced arthritis by a T-cell hybridoma

The present study elucidates the suppression of collagen-induced arthritis (CIA) by T-suppressor cells through the analysis of the joints and articular cartilage of mice suppressed for CIA by a T-cell hybridoma. T-cell hybridomas (T101N and T104B1) were derived from the somatic cell fusion of splenic and thymic cells of mice suppressed for CIA and the AKR BW 5147 thymoma cell line. CIA mice administered 1 X 10(5) T101N hybridoma cells intravenously were observed to have reduced hind paw pathology scores as well as reduced edema, compared with CIA mice or CIA mice administered 1 X 10(5) cells of a control T-cell hybridoma, T104B1. The hind paw articular cartilage of joints from mice with CIA administered T101N cells resembled normal joint architecture in histologic staining and alignment of articular cartilage surfaces. The histopathology observed in joints of mice administered T104B1 hybridoma cells resembled that of CIA mice with large pannus formation, fibrous bridging of the joint, soft-tissue metaplasia, and joint disorganization. The data indicate that specific T-cell hybridoma cell lines can modulate the joint histopathology observed in CIA to resemble the joint architecture of noninflammatory joints.

Attenuation of collagen arthritis and modulation of delayed-type hypersensitivity by type II collagen reactive T-cell lines

T-cell lines were established from the lymph node cells of syngeneic Louvain (LOU) rats previously immunized with native chick type II collagen (CII) emulsified in incomplete Freund's adjuvant. The CII lines proliferated in vitro to type II collagen but not to type I collagen, ovalbumin (OV), or PPD. Control lines, developed from LOU rats immunized with OV emulsified in complete Freund's adjuvant, were OV specific because they did not respond to other antigens in vitro. CII line cells could adoptively transfer delayed-type hypersensitivity (DTH) but did not induce IgG antibody production to collagen. Moreover, the intravenous administration of 2 X 10(7) CII line cells prevented the subsequent induction of collagen arthritis following immunization and suppressed DTH to collagen without affecting antibody responses in the recipients. Spleen cells, but not sera, from these resistant rats decreased CII line reactivity in vitro. OV or irradiated CII lines had no effect on clinical or immunologic parameters in this model. These findings demonstrate protection from arthritis afforded by T-cell line transfer and suggest that the phenomenon results from down-regulation of the recipients' cellular immunity to collagen.

Passive transfer studies with type II collagen antibody in B10.D2/old and new line and C57Bl/6 normal and beige (Chediak-Higashi) strains: evidence of important roles for C5 and multiple inflammatory cell types in the development of erosive arthritis

C5-normal B10.D2/new line mice were susceptible to passively transferred arthritis from purified type II collagen antibody, and in vitro studies demonstrated that, when bound to cartilage, this antibody readily activated complement C5 to C5a. C5-deficient B10.D2/old line mice failed to develop passively transferred arthritis, despite the deposition of antibody and C3 along the cartilage surface. C57Bl/6 mice were susceptible to passively transferred arthritis, which was characterized in histopathologic studies as an erosive synovitis involving multiple inflammatory cell types. In contrast, neither clinical nor histologic evidence of arthritis was observed in C57Bl/6 mice with the beige mutation (Chediak-Higashi syndrome).

Passive transfer of collagen arthritis: heterogeneity of anti-collagen IgG

Using a combination of affinity chromatography procedures, anticollagen IgG was fractionated into three distinct populations. One population reacted only to conformational determinants, another population reacted only to structural determinants, and the third population reacted to both conformation and structural determinants. When these populations were tested for their arthritogenicity, only those fractions that reacted to conformational and to conformational and structural determinants were active in inducing clinical arthritis. Immunofluorescence analysis of the hind paw of recipient rats indicated that antibodies directed only to conformational and to both conformational and structural determinants bound to articular cartilage and activated the complement system. Antibodies directed strictly to structural determinants did not bind to articular cartilage and were nonarthritogenic.