The cellular basis of adjuvant arthritis. II. Characterization of the cells mediating passive transfer

Spondyloarthritis, Acute Anterior Uveitis, and Fungi: Updating the Catterall-King Hypothesis

Spondyloarthritis is a common type of arthritis which affects mostly adults. It consists of idiopathic chronic inflammation of the spine, joints, eyes, skin, gut, and prostate. Inflammation is often asymptomatic, especially in the gut and prostate. The HLA-B*27 allele group, which presents intracellular peptides to CD8+ T cells, is by far the strongest risk factor for spondyloarthritis. The precise mechanisms and antigens remain unknown. In 1959, Catterall and King advanced a novel hypothesis explaining the etiology of spondyloarthritis: an as-yet-unrecognized sexually acquired microbe would be causing all spondyloarthritis types, including acute anterior uveitis. Recent studies suggest an unrecognized sexually acquired fungal infection may be involved in prostate cancer and perhaps multiple sclerosis. This warrants reanalyzing the Catterall-King hypothesis based on the current literature. In the last decade, many links between spondyloarthritis and fungal infections have been found. Antibodies against the fungal cell wall component mannan are elevated in spondyloarthritis. Functional polymorphisms in genes regulating the innate immune response against fungi have been associated with spondyloarthritis (CARD9 and IL23R). Psoriasis and inflammatory bowel disease, two common comorbidities of spondyloarthritis, are both strongly associated with fungi. Evidence reviewed here lends credence to the Catterall-King hypothesis and implicates a common fungal etiology in prostate cancer, benign prostatic hyperplasia, multiple sclerosis, psoriasis, inflammatory bowel disease, and spondyloarthritis. However, the evidence available at this time is insufficient to definitely confirm this hypothesis. Future studies investigating the microbiome in relation to these conditions should screen specimens for fungi in addition to bacteria. Future clinical studies of spondyloarthritis should consider antifungals which are effective in psoriasis and multiple sclerosis, such as dimethyl fumarate and nystatin.

Boi-ogi-to (TJ-20), a Kampo Formula, Suppresses the Inflammatory Bone Destruction and the Expression of Cytokines in the Synovia of Ankle Joints of Adjuvant Arthritic Rats

TJ-20 is a formula consisting of 6 herbs that has been used in the clinical treatment of rheumatoid arthritis (RA) in China and Japan for centuries. However, scientific evidence of the effects of TJ-20 has not been established. In the present study, we focused on the therapeutic effects and investigated the main function of TJ-20 on adjuvant arthritis (AA), an animal model of RA, which was induced with complete Freund's adjuvant (CFA). TJ-20 was administered orally at 600 mg/kg once a day from 0, 7, and 10 days to 8 weeks after the CFA treatment. TJ-20 significantly ameliorated inflammatory progression and bone destruction in AA in a time-dependent manner. Furthermore, TJ-20 significantly reduced the increased changes in a number of macrophages and helper T cells. Moreover, TJ-20 suppressed the expression of TNF-α whereas it augmented the expression of IL-10 and attenuated Th1 cells responses in the synovia of the ankle joint. Therefore, TJ-20 regulated the expression of proinflammatory and anti-inflammatory cytokines in macrophages and Th1/Th2 balance in the synovia of ankle joints in AA rats. These results suggest the positive anti-inflammatory effect of TJ-20 and provide a scientific basis for the clinical use of TJ-20 for RA.

Microarray analysis reveals the molecular basis of antiarthritic activity of huo-luo-xiao-ling dan

Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune origin. Huo-luo-xiao-ling dan (HLXL) is an herbal mixture that has been used in traditional Chinese medicine over several decades to treat chronic inflammatory diseases including RA. However, the mechanism of the anti-arthritic action of this herbal remedy is poorly understood at the molecular level. In this study, we determined by microarray analysis the effects of HLXL on the global gene expression profile of the draining lymph node cells (LNC) in the rat adjuvant arthritis (AA) model of human RA. In LNC restimulated in vitro with the disease-related antigen mycobacterial heat-shock protein 65 (Bhsp65), 84 differentially expressed genes (DEG) (64 upregulated and 20 downregulated) versus 120 DEG (94 upregulated and 26 downregulated) were identified in HLXL-treated versus vehicle (Water)-treated rats, respectively, and 62 DEG (45 upregulated and 17 downregulated) were shared between the two groups. The most affected pathways in response to HLXL treatment included immune response, inflammation, cellular proliferation and apoptosis, and metabolic processes, many of which are directly relevant to arthritis pathogenesis. These results would advance our understanding of the mechanisms underlying the anti-arthritic activity of HLXL.

The gene expression profile of preclinical autoimmune arthritis and its modulation by a tolerogenic disease-protective antigenic challenge

Introduction

Autoimmune inflammation is a characteristic feature of rheumatoid arthritis (RA) and other autoimmune diseases. In the natural course of human autoimmune diseases, it is rather difficult to pinpoint the precise timing of the initial event that triggers the cascade of pathogenic events that later culminate into clinically overt disease. Therefore, it is a challenge to examine the early preclinical events in these disorders. Animal models are an invaluable resource in this regard. Furthermore, considering the complex nature of the pathogenic immune events in arthritis, microarray analysis offers a versatile tool to define the dynamic patterns of gene expression during the disease course.

Methods

In this study, we defined the profiles of gene expression at different phases of adjuvant arthritis (AA) in Lewis rats and compared them with those of antigen mycobacterial heat shock protein 65 (Bhsp65)-tolerized syngeneic rats. Purified total RNA (100 ng) extracted from the draining lymph node cells was used to generate biotin-labeled fragment cRNA, which was then hybridized with an oligonucleotide-based DNA microarray chip. Significance analysis of microarrays was used to compare gene expression levels between the two different groups by limiting the false discovery rate to < 5%. Some of the data were further analyzed using a fold change ≥2.0 as the cutoff. The gene expression of select genes was validated by quantitative real-time PCR.

Results

Intriguingly, the most dramatic changes in gene expression in the draining lymphoid tissue ex vivo were observed at the preclinical (incubation) phase of the disease. The affected genes represented many of the known proteins that participate in the cellular immune response. Interestingly, the preclinical gene expression profile was significantly altered by a disease-modulating, antigen-based tolerogenic regimen. The changes mostly included upregulation of several genes, suggesting that immune tolerance suppressed disease by activating disease-regulating pathways. We identified a molecular signature comprising at least 12 arthritis-related genes altered by Bhsp65-induced tolerance.

Conclusions

This is the first report of microarray analysis in the rat AA model. The results of this study not only advance our understanding of the early phase events in autoimmune arthritis but also help in identifying potential targets for the immunomodulation of RA.

Rodent preclinical models for developing novel antiarthritic molecules: comparative biology and preferred methods for evaluating efficacy

Rodent models of immune-mediated arthritis (RMIA) are the conventional approach to evaluating mechanisms of inflammatory joint disease and the comparative efficacy of antiarthritic agents. Rat adjuvant-induced (AIA), collagen-induced (CIA), and streptococcal cell wall-induced (SCW) arthritides are preferred models of the joint pathology that occurs in human rheumatoid arthritis (RA). Lesions of AIA are most severe and consistent; structural and immunological changes of CIA best resemble RA. Lesion extent and severity in RMIA depends on experimental methodology (inciting agent, adjuvant, etc.) and individual physiologic parameters (age, genetics, hormonal status, etc.). The effectiveness of antiarthritic molecules varies with the agent, therapeutic regimen, and choice of RMIA. All RMIA are driven by overactivity of proinflammatory pathways, but the dominant molecules differ among the models. Hence, as with the human clinical experience, the efficacy of various antiarthritic molecules differs among RMIA, especially when the agent is a specific cytokine inhibitor.

Host immune factors regulating fibrosis

Mononuclear cells produce lymphokines and monokines, the function of which is to initiate the mobilization, proliferation and differentiation of additional mononuclear cells in an inflammatory site. In addition, these inflammatory cells produce biologically active mediators which modulate the functions of certain non-inflammatory cell targets. Lymphokines and monokines can stimulate chemotaxis, division, and matrix synthesis by connective tissue fibroblasts. Additional mononuclear cell-derived mediators can inhibit or suppress these fibroblast functions, implicating the host immune system in the regulation of connective tissue metabolism associated with an inflammatory response. Altering the balance of the production and/or release of these connective tissue-active agents could result in excess fibroblast growth and matrix synthesis (fibrosis) and its pathological manifestations.

Regulation of autoimmune arthritis by the pro-inflammatory cytokine interferon-gamma

The pathogenesis of T cell-mediated diseases like rheumatoid arthritis (RA) has typically been explained in the context of the Th1-Th2 paradigm: the initiation/propagation by pro-inflammatory cytokines, and downregulation by Th2 cytokines. However, in our study based on the adjuvant-induced arthritis (AA) model of RA, we observed that Lewis (LEW) (RT.1(l)) rats at the recovery phase of AA showed the highest level of IFN-gamma in recall response to mycobacterial heat-shock protein 65 (Bhsp65), whereas AA-resistant Wistar-Kyoto (WKY) (RT.1(l)) rats secreted high levels of IFN-gamma much earlier following disease induction. However, no significant secretion of IL-10 or TGF-beta was observed in either strain. Furthermore, pre-treatment of LEW rats with a peptide of self (rat) hsp65 (R465), which induced T cells secreting predominantly IFN-gamma, afforded protection against AA and decreased IL-17 expression by the arthritogenic epitope-restimulated T cells. These results provide a novel perspective on the pathogenesis of autoimmune arthritis.

The anti-inflammatory effect of A3 adenosine receptor agonists: a novel targeted therapy for rheumatoid arthritis

Targeting the A(3) adenosine receptor (A(3)AR) to combat inflammation is a new concept based on two findings. First, A(3)AR is highly expressed in inflammatory cells, whereas low expression is found in normal tissues. This receptor was also found to be overexpressed in peripheral blood mononuclear cells, reflecting receptor status in the remote inflammatory process. Second, A(3)AR activation with a specific agonist induces de-regulation of the NF-kappaB signaling pathway in inflammatory cells, as well as initiation of immunomodulatory effects. The A(3)AR agonist CF-101 (known generically as IB-MECA) induces anti-inflammatory effects in experimental animal models of collagen- and adjuvant-induced arthritis. Combined therapy with CF-101 and methotrexate in adjuvant-induced arthritis rats yielded an additive anti-inflammatory effect. Methotrexate induced upregulation of A(3)AR, rendering the inflammatory cells more susceptible to CF-101. In Phase I and in Phase IIa human studies, CF-101 was safe, well tolerated and showed strong evidence of an anti-inflammatory effect in rheumatoid arthritis patients. In peripheral blood mononuclear cells withdrawn from the patients at base line, a statistically significant correlation between A(3)AR expression level and response to the drug was noted. It is suggested that A(3)AR may serve as a biologic marker to predict patient response to the drug. Taken together, this information suggests that A(3)AR agonists may be a new family of orally bioavailable drugs to be developed as potent inhibitors of autoimmune-inflammatory diseases.

Pristane-induced arthritis in the rat

A chronic relapsing arthritis develops after a single subcutaneous injection of small amounts of pristane; the pristane induced arthritis (PIA) model in the rat. PIA is characterized by a sudden onset of disease 2 wk after induction. The main pathological features of PIA include edema accompanied by an acute phase response, infiltration into the joint of mononuclear and polymorphonuclear cells, pannus formation, and erosion of cartilage and bone. PIA is a disease that is largely T-cell dependent that can be adoptively transferred by activated CD4+ T-cells. PIA in rats is followed clinically by macroscopic scoring and is characterized by an early acute phase of severe inflammation after onset that eventually gradually disappears to be followed by less severe relapsing phases of new inflamed joints and increasing cartilage erosion and joint deformity. PIA can be diagnosed by biochemical analyzes in plasma that reflects systemic inflammation (alpha1-acid glycoprotein (AGP) and IL-6) and cartilage erosion (COMP).

Recruitment and proliferation of CD4+ T cells in synovium following adoptive transfer of adjuvant-induced arthritis

Adjuvant-induced arthritis can be transferred to naive Dark Agouti (DA) strain (DA.CD45.1) rats by thoracic duct (TD) lymphocytes. Disease can be re-induced in convalescent rats by further transfer of arthritogenic cells, suggesting that resolution of the adoptive disease is not due to active regulation. To examine whether resolution is due to exhaustion of effector cells, we transferred the disease to DA.CD45.1 recipients, using CD4+ T cells from DA.CD45.2 donors. At the height of the adoptively transferred disease, donor cells comprised only 5-10% of recirculating CD4+ T cells but they accounted for approximately 40% of the CD4+ T cells in synovium-rich tissues of the hind paws. Approximately 65% of the donor cells in the synovium expressed a marker of proliferation (Ki-67 antigen). Division of CD4+ T cells continued in shielded paws after suppression of the recirculating pool of lymphocytes by selective irradiation. Intravenously injected CD4+ TD T lymphoblasts from arthritic donors were recruited to normal paws and, in greater numbers, to paws of animals with existing arthritis. Survival of the [125I]iodo-deoxyuridine-labeled lymphoblasts was greater in animals with existing arthritis. We conclude that effector CD4+ T cells in target tissues can proliferate in response to autoantigens and exhibit enhanced survival. However, without a continuous supply, adoptively transferred effector cells do not produce autonomous local disease, due to limits to their lifespan and ability to replicate indefinitely.

Pristane, a non-antigenic adjuvant, induces MHC class II-restricted, arthritogenic T cells in the rat

Pristane-induced arthritis (PIA) in rats, a model for rheumatoid arthritis (RA), is a T cell-dependent disease. However, pristane itself is a lipid and unable to form a stable complex with a MHC class II molecule. Therefore, the specificity and function of the T cells in PIA are as unclear as in rheumatoid arthritis. In this study, we show that activated CD4+ alphabetaT cells, which target peripheral joints, transfer PIA. The pristane-primed T cells are of oligo or polyclonal origin as determined by their arthritogenicity after stimulation with several mitogenic anti-TCRVbeta and anti-TCRValpha mAbs. Arthritogenic cells secreted IFN-gamma and TNF-alpha (but not IL-4) when stimulated with Con A in vitro, and pretreatments of recipient rats with either anti-IFN-gamma or a recombinant TNF-alpha receptor before transfer ameliorated arthritis development. Most importantly, we show that these T cells are MHC class II restricted, because treatment with Abs against either DQ or DR molecules ameliorates arthritis development. The MHC class II restriction was confirmed by transferring donor T cells to irradiated recipients that were syngenic, semiallogenic, or allogenic to MHC class II molecules, in which only syngenic and semiallogenic recipients developed arthritis. These data suggest that the in vivo administration of a non-antigenic adjuvant, like pristane, activates CD4+ alphabetaT cells that are MHC class II restricted and arthritogenic.

Blockade of IFN-gamma does not affect the arthritogenicity of T cells generated during the induction of adjuvant arthritis but exacerbates the polyarthritis produced by adoptive transfer of arthritogenic effector cells

IFN-gamma production is prominent in some models of autoimmune disease, including adjuvant arthritis (AA), but the role of IFN-gamma in the pathogenesis of these diseases is uncertain. Experimental manipulation (administration of cytokine, blocking cytokine action with specific antibody, disruption of genes encoding the cytokine or its receptor) has revealed both pro- and anti-inflammatory effects, depending on the nature of the manipulation and the timing of the treatment. We examined separately the effects of cytokine blockade during the afferent and efferent phases of AA in Dark Agouti rats, using an adoptive transfer system. Effects of IFN-gamma on the efferent phase were investigated by treating recipients with mAb DB-1, which blocks the activity of rat IFN-gamma. When treatment was commenced before cell transfer, the resulting polyarthritis was more severe than in controls treated with normal IgG. Commencing treatment after the adoptively transferred disease had become established caused neither amelioration nor exacerbation, but did cause some delay in resolution. In contrast, treatment of donors did not appear to affect the generation of arthritogenic cells. The main effect of IFN-gamma appears to be modulation of the arthritogenicity of the migratory effector T cells that can transfer AA.

CD134 as target for specific drug delivery to auto-aggressive CD4+ T cells in adjuvant arthritis

T cells have an important role during the development of autoimmune diseases. In adjuvant arthritis, a model for rheumatoid arthritis, we found that the percentage of CD4+ T cells expressing the activation marker CD134 (OX40 antigen) was elevated before disease onset. Moreover, these CD134+ T cells showed a specific proliferative response to the disease-associated epitope of mycobacterial heat shock protein 60, indicating that this subset contains auto-aggressive T cells. We studied the usefulness of CD134 as a molecular target for immune intervention in arthritis by using liposomes coated with a CD134-directed monoclonal antibody as a drug targeting system. Injection of anti-CD134 liposomes subcutaneously in the hind paws of pre-arthritic rats resulted in targeting of the majority of CD4+CD134+ T cells in the popliteal lymph nodes. Furthermore, we showed that anti-CD134 liposomes bound to activated T cells were not internalized. However, drug delivery by these liposomes could be established by loading anti-CD134 liposomes with the dipalmitate-derivatized cytostatic agent 5'-fluorodeoxyuridine. These liposomes specifically inhibited the proliferation of activated CD134+ T cells in vitro, and treatment with anti-CD134 liposomes containing 5'-fluorodeoxyuridine resulted in the amelioration of adjuvant arthritis. Thus, CD134 can be used as a marker for auto-aggressive CD4+ T cells early in arthritis, and specific liposomal targeting of drugs to these cells via CD134 can be employed to downregulate disease development.

Differential roles of VLA-4(CD49d/CD29) and LFA-1(CD11a/CD18) integrins and E- and P-selectin during developing and established active or adoptively transferred adjuvant arthritis in the rat

The role of the integrins VLA-4 and LFA-1 and of the selectin adhesion molecules in autoimmune arthritis was investigated. Adjuvant arthritis was induced in Lewis rats by active immunization (s.c.) with Mycobacterium butyricum or by adoptive transfer of immune T cells. With active adjuvant arthritis, Lewis rats develop maximal polyarticular joint inflammation and migration of radiolabelled (111In and 51Cr) blood neutrophils and monocytes to the joints 14 days post Mycobacterium butyricum immunization. Using blocking monoclonal antibodies we osbserved that at this stage monocyte recruitment was dependent (85%) on P-selectin plus VLA-4 (alpha4B1) and neutrophil recruitment depended (> 80%) on P-selectin plus LFA-1 (CD11a/CD18). E-selectin played a minimal role in inflammatory cell recruitment to the already inflamed joint. In contrast, during the development of active adjuvant arthritis, blockade of P-selectin beginning at day 5 post-immunization had no effect on subsequent arthritis. However, E-selectin blockade at this stage reduced arthritic scores by 70% (P < 0.01) and combined E-selectin plus VLA-4 blockade prevented development of arthritis. Either treatment nearly abolished neutrophil and monocyte recruitment to joints at day 14 and prevented cartilage damage. VLA-4 blockade alone was less effective. Adoptive T-cell transfer of adjuvant arthritis to naive rats employed spleen/lymph node lymphocytes from Mycobacterium butyricum immunized rats stimulated with Concanavalin A in vitro (48 h). E-selectin +/- P-selectin blockade had no effect on the development of adoptive arthritis. However, VLA-4 integrin blockade inhibited adoptive arthritis severity by 55% (P < 0.01). LFA-1 blockade had no effect. In adoptive adjuvant arthritis, inhibition of arthritis clinically and by histology was essentially complete (> 90%) when E- and P-selectin blockade was combined with VLA-4 blockade. Thus, in the development of actively induced arthritis E-selectin plays an important role, likely mediating early antigen reactive T-cell recruitment to joints. In contrast, VLA-4 and multiple selectin mechanisms are involved in arthritis induction by ex vivo restimulated arthritogenic T cells. Furthermore, in actively induced adjuvant arthritis, P- and E-selectin and VLA-4 are differently important in the initiation of arthritis, and at the time of fully developed joint inflammation.

Positional identification of Ncf1 as a gene that regulates arthritis severity in rats

The identification of genes underlying quantitative-trait loci (QTL) for complex diseases, such as rheumatoid arthritis, is a challenging and difficult task for the human genome project. Through positional cloning of the Pia4 QTL in rats, we found that a naturally occurring polymorphism of Ncf1 (encoding neutrophil cytosolic factor 1, a component of the NADPH oxidase complex) regulates arthritis severity. The disease-related allele of Ncf1 has reduced oxidative burst response and promotes activation of arthritogenic T cells. Pharmacological treatment with substances that activate the NADPH oxidase complex is shown to ameliorate arthritis. Hence, Ncf1 is associated with a new autoimmune mechanism leading to severe destructive arthritis, notably similar to rheumatoid arthritis in humans.

Protective effect of prior acute immune challenge, but not footshock, on inflammation in the rat

Previous studies have revealed that a single exposure to an acute stress or acute immune stimulus can produce long-lasting changes in the activity and responsiveness of the hypothalamo-pituitary-adrenal (HPA) axis. The HPA axis is believed to be an important component in determining the susceptibility and severity of inflammation in autoimmune disease models such as adjuvant-induced arthritis (AA). In the present study we have tested the hypothesis that a single exposure to either footshock or lipopolysaccharide (LPS) 3 weeks prior to adjuvant injection can alter susceptibility to AA. Changes in HPA axis parameters were also determined. The results demonstrated that prior exposure to LPS conferred resistance to inflammation in AA, which was not related to a delay in onset of inflammation but rather an alteration in susceptibility. In contrast, prior exposure to the acute stress of footshock did not alter susceptibility. HPA axis parameters were increased in adjuvant-injected rats whether inflammation was present or not. These data suggest that prior exposure to acute immune stimuli, but not to acute footshock stress, may alter susceptibility to inflammation in the rat AA model. These changes in susceptibility do not appear to be solely mediated by increases in HPA axis activity, which were apparent in all AA groups irrespective of the presence of inflammation.

Treatment of experimental adjuvant arthritis with the combination of methotrexate and lyophilized Enterococcus faecium enriched with organic selenium

The efficacy of combination therapy with methotrexate (MTX) and probiotic bacteria Enterococcus faecium enriched with organic selenium (EFSe) in rats with adjuvant arthritis was determined. Rats with adjuvant arthritis were given MTX (0.3 mg/kg 2-times weekly, orally); lyophilized E. faecium enriched with Se (15 mg/kg, 5 d per week, orally); and a combination of MTX plus EFSe for a period of 50 d from the immunization. Levels of serum albumin, serum nitrite/nitrate concentrations, changes in hind paw swelling, arthrogram score, bone erosions, whole body bone mineral density (BMD) and bone mineral content (BMC) were assayed in the rats as variables of inflammation and destructive arthritis-associated changes. Treatment with MTX and with the combination MTX + EFSe significantly inhibited markers of both inflammation and arthritis. Significant differences in favor of combination therapy with MTX + EFSe as compared to MTX alone were seen in serum albumin concentration, hind paw swelling and arthrogram score. Reductions in radiographic scores were also more pronounced in the combination therapy group. Combination therapy, but not MTX alone, inhibited the reduction of BMD and BMC; treatment with lyophilized EFSe alone had no significant effect on adjuvant arthritis in rats. The potent therapeutic effect of low dosage MTX therapy in combination with lyophilized EFSe on adjuvant arthritis in rats was shown.

Balance of Th1/Th2 cytokines associated with the preventive effect of incomplete Freund's adjuvant on the development of adjuvant arthritis in LEW rats

Complete Freund's adjuvant (CFA) could induce adjuvant arthritis (AA) in LEW rats and incomplete Freund's adjuvant (IFA) could induce oil induced arthritis (OIA) in DA but not in LEW rats. Lymph node cells (LNCs) from these AA and OIA rats showed increased mRNA expression of IFN-gamma, IL-2 and TNF-alpha but not IL-4. LNCs from IFA immunized LEW rats showed increased expression of IL-4, reduced expression of IFN-gamma and TNF-alpha and no IL-2, in contrast to IFA immunized DA rats. The pretreatment of IFA before CFA challenge could completely prevent AA in LEW rats and their LNCs showed increased expression of IL-4 and IFN-gamma but not IL-2 and TNF-alpha. In F1 (LEW x DA) rats, IFA could not induce OIA but the pretreatment of IFA before CFA challenge could induce very mild AA with 80% incidence, LNCs showing an elevated expression of all the above cytokines. These findings suggest that increased Th1 cytokine expression is associated with disease development and that increased IL-4 expression or the balance of Th2 over Th1 cytokine expression plays an important regulatory role in disease development.

Immunohistochemical study of lymphoid tissues in adjuvant arthritis (AA) by image analysis; relationship with synovial lesions

The aim of this study was to examine leucocyte populations in lymphoid organs during AA and to ascertain the relationship with lesions in synovial joints. Popliteal lymph nodes, spleen and knee synovial membranes were removed from both healthy and AA rats at intervals of 3-4 days over a 3-week period. Cryostat sections were stained with MoAbs directed against lymphocyte and macrophage subpopulations, and studied by image analysis. Throughout the arthritic period, high numbers of ED1+ and ED3+ macrophages were seen in both lymphoid compartments and intercellular adhesion molecule-1 (ICAM-1) expression also increased in some zones of lymph nodes and spleen. The percentages of CD4+ and CD8+ cells rose in the splenic zones studied but fell in the lymph node cortex. Very few natural killer (NK) cells were found in lymphoid tissues, but the number rose after AA induction. In synovia from AA rats, ED2+ macrophages proliferated but alpha/beta T cell infiltration was only occasionally observed, accompanied by ED1+ cells and ICAM-1 expression. In conclusion, synovitis developing after AA induction seems to be caused directly by macrophages and indirectly by lymphocytes placed both in popliteal lymph nodes and spleen.

The preventive effects of incomplete Freund's adjuvant and other vehicles on the development of adjuvant-induced arthritis in Lewis rats

The present study showed a novel finding that the development of adjuvant-induced arthritis (AA) in Lewis rats was completely prevented by incomplete Freund's adjuvant (IFA) injected 21 or 28 days before complete Freund's adjuvant (CFA) challenge. Hexadecane also completely prevented AA and squalane, methyl oleate and pristane moderately prevented AA, though pristane by itself induced mild arthritis in two out of five rats. Concanavalin A-stimulated lymph node cells (LNCs) isolated from AA rats were able to adoptively transfer the severe polyarthritis to all the naive recipients or even to the IFA pretreated recipients with earlier onset and more rapid progression than those of AA. The LNCs from the donors who had been pretreated with IFA and subsequently challenged with CFA could induce mild arthritis in only two out of eight naive recipients, whereas all the recipients who were challenged with CFA immediately after intravenous injection of these LNCs developed significantly less severe arthritis. However, the LNCs from IFA-pretreated donors failed to prevent AA. According to the T helper type 1 (Th1)/Th2 paradigm, it was suggested that the adjuvant-active vehicles such as IFA, hexadecane, squalane, methyl oleate and pristane, can affect and deviate the Th1/Th2 balance of immune responses in host. CFA could promote the propagation of Th2 cells rather than Th1 cells in these vehicle-pretreated rats through as yet undetermined mechanisms, eventually resulting in the prevention of AA. Finally, we discussed a regulatory role of adjuvant vehicles for induction and suppression of AA.

Complement activation and inhibition in experimental models of arthritis

Complement activation has been implicated as a pathological process in a number of inflammatory and autoimmune disorders including chronic rheumatoid arthritis (RA). Animal models of experimental arthritis have been widely used to investigate the pathogenesis of RA and also in the development of novel therapies. Many of these models are complement-dependent and both incidence and progression of disease can be influenced by complement inhibition. In certain situations, local inhibition is of greater therapeutic benefit than systemic decomplementation. An increasing awareness and availability of a wide range of naturally occurring complement regulatory proteins can now offer a more targeted approach to complement inhibition while the availability of novel engineering strategies has also improved the efficiency of this process. The success of complement inhibition in the experimental models described should offer a novel therapeutic approach to the treatment of human inflammatory arthritis.

Administration of interferon-g to pregnant rats reverses the depressed adjuvant-induced arthritis of their chronically Trypanosoma cruzi-infected offspring

We demonstrated that administration of interferon gamma (IFN-gamma) to the inbred "I" strain of pregnant rats conferred partial resistance on their offspring to challenge with Trypanosoma cruzi. We now examine if this intervention also modifies the reportedly immunodepressed cellular responses which occur during chronic infection. Offspring were born to mothers undergoing one of the following procedures during gestation: subcutaneous injections of recombinant rat IFN-gamma, 50,000 IU/rat, five times/week for 3 weeks, which was started on the day of mating (IFN-Mo); infection with 10(6) trypomastigotes of T. cruzi at 7, 14, and 21 days after mating plus IFN-gamma treatment as given to the former group (TcIFN-Mo); the same protocol except that physiological saline was injected instead of IFN-gamma (Te-Mo); injection of physiological saline only (control-Mo). All offspring groups (N = 8-10/group) were infected at weaning and were assessed 90 days later for their adjuvant-induced arthritic response or levels of major T cell subsets in spleen and lymph nodes. TcIFN-Mo and IFN-Mo offspring showed a reestablished arthritic response, which remained within the range seen in controls. Immunolabeling studies on parallel groups of 90-day-infected offspring showed that the inverse CD4/CD8 cell ratio that is usually seen in lymphoid organs from these chronically infected rats (median 0.61) appeared to have recovered in the TcIFN-Mo and IFN-Mo groups (median 1.66 and 1.78, respectively) and was not different from uninfected controls (1.96). These studies indicate that early stimulation with IFN-gamma is able to reverse the immunosuppressive state that is usually present during the chronic period of the experimental infection.

Alterations of lymphocyte populations in lymph nodes but not in spleen during the latency period of adjuvant arthritis

The aim of this study was to analyze potential imbalances in lymphocyte populations from regional lymph nodes (LN) and spleen occurring before the development of the outer inflammation of adjuvant arthritis (AA). Percentages and absolute numbers of CD5+, CD4+, CD8+, Ig+, I-A+, NKR-P1+ and TCRgammadelta+ cells were determined. No differences in percentages of gammadelta T or NK cells were found either in LN or spleen, thus ruling out an important role of these minor subpopulations in these early stages of AA. While no significant lymphocyte imbalances were observed in spleen, an increase in the percentage of B lymphocytes was found in regional LN. Moreover, a high proliferation of CD8+ cells was observed when measuring absolute numbers of LN lymphocytes, thus producing an imbalance in the CD4/CD8 ratio at very early stages of the inflammatory process. These findings suggest a role for CD8+ and B lymphocytes in the latency period of AA at the LN level. Our results indicate a primary role for lymph nodes in initiating the inflammation of AA, whereas cells from the spleen probably play a secondary role.

Successful Induction of Adjuvant Arthritis in Mice by Treatment with a Monoclonal Antibody Against IL-4

Adjuvant arthritis (AA) is an experimental model of autoimmune disease in rats induced by immunization with Mycobacterium tuberculosis (MT). Induction of AA in other species, including mice, has been shown to be difficult. In the present study, we found that AA could be induced in mice if the animals were treated with a mAb (11B11 mAb) against IL-4. Histologically, the joints exhibited synovial edema with infiltration of many neutrophils in the early phase of inflammation. In its late phase, there were proliferation of synovium, cell infiltrate in which mononuclear cells predominated, and destruction of cartilage and subchondral bone. The joint inflammation was passively transferred to normal syngeneic recipient mice with lymphoid cells but not with sera from mice immunized with MT followed by treatment with the anti-IL-4 Ab. Delayed-type hypersensitivity (DTH) and proliferative responses of lymphoid cells to purified protein derivative were markedly augmented in 11B11 mAb-treated mice. Furthermore, the induction of arthritis was associated with a marked decrease in IL-4 secretion but a significant increase in IFN-γ and IL-2 production. Thus, the neutralization of IL-4 by an anti-IL-4 Ab appears to be required for the induction of AA in mice.

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.

Involvement of macrophage migration inhibitory factor in the evolution of rat adjuvant arthritis

OBJECTIVE

Recent studies have established an essential role for macrophage migration inhibitory factor (MIF) in T cell and macrophage activation, both of which are characteristics of rat adjuvant arthritis. This study investigated the role of MIF in early adjuvant arthritis.

METHODS

MIF was detected in rat synovium by immunohistochemistry and enzyme-linked immunosorbent assay using specific monoclonal antibodies (MAb). Anti-MIF MAb treatment was administered, and the effects on clinical aspects of adjuvant arthritis were assessed.

RESULTS

MIF was absent from normal rat synovium prior to adjuvant injection, but was detectable on day 4 after injection (6 days before the onset of clinical disease) and was colocalized with ED-1+ macrophages throughout the evolution of the disease. Levels of MIF were increased in established adjuvant arthritis sera, and adjuvant arthritis synovial macrophages released MIF at a mean +/- SEM concentration of 607.9 +/- 201.5 pg/ml. Anti-MIF treatment led to profound, dose-dependent inhibition of the adjuvant arthritis clinical score, paw swelling, and synovial lavage leukocyte numbers (P < 0.001), and also resulted in reduced synovial macrophage and T cell accumulation.

CONCLUSION

These findings demonstrate an important role for MIF in the evolution of rat adjuvant arthritis.

Evidence for preferential T cell receptor V beta gene usage and T cell clonal expansion in the synovium of BB rats with early-onset collagen-induced arthritis

Type II collagen (CII) is a potent arthritogen in the BB rat. To determine whether a restricted group of T cells is involved in the pathogenesis of collagen-induced arthritis, lymphocytes from synovium, peripheral blood, and lymph nodes of arthritic rats were studied for T cell receptor (TCR) V beta gene usage using polymerase chain reaction (PCR). Oligoclonal TCR V beta usage was found only in synovium recovered day 2 post-arthritis onset, but not day 7; lymph node and peripheral blood T cells showed diverse TCR usage at both times. To determine whether T cell local clonal expansion occurred in synovium at day 2 of arthritis, cDNA for four TCR beta families was sequenced through VDJ regions. Strong selective expansion of TCR V beta 8.2, 4, and 17 was noted. Importantly, the dominant clonotype of V beta 8.2 was identical to that of a lymph node-derived T hybridoma specific for the immunodominant epitope in CII(181-210). Cells from synovium (day 2 postonset) analyzed by flow cytometry also showed V beta 8.2+ cell enrichment. These observations, plus finding that T cells from inflamed synovium respond to CII(181-201) in vitro, suggest the local recruitment and clonal expansion of some T cells families, possibly driven by autologous CII released during cartilage degradation.

Prevention of splenic granuloma formation in adjuvant arthritis by 2-acetyl-4-tetrahydroxybutylimidazole (THI)

Adjuvant-induced arthritis (AA) in Lewis rats is a widely used model of chronic inflammatory arthritis. Non-articular features such as weight loss and necrotizing granulomas of the spleen and lymph nodes also occur in this model. The compound 2-acetyl-4-tetrahydroxybutylimidazole (THI) marginally delayed the development of AA. However, this agent had no effect on the incidence or severity of disease. In contrast, THI totally prevented granuloma formation in the spleen and associated splenomegaly. We conclude that THI may be a useful adjunctive agent for some inflammatory diseases.

Nitric oxide production during adjuvant-induced and collagen-induced arthritis

OBJECTIVE

To investigate the role of nitric oxide (NO) production and NO synthase (NOS) induction during adjuvant-induced arthritis (AIA) and collagen-induced arthritis (CIA) in Dark Agouti rats.

METHODS

Urinary nitrate excretion and immune NOS (INOS) messenger RNA (mRNA) expression were measured in the joint, lymph node, spleen, and liver tissues following the induction of either AIA or CIA.

RESULTS

Urinary nitrate excretion and iNOS mRNA expression increased substantially during joint inflammation in both models of arthritis. However, the increases in urinary nitrate excretion and iNOS mRNA expression observed in the joint, liver, and spleen tissues during AIA were greater than those observed during CIA, although iNOS induction in the lymph nodes was similar for both models. A prior injection with Mycobacterium bovis heat-shock protein resulted in suppression of arthritis and NO production in AIA, but not in CIA.

CONCLUSION

Differences in NO production during AIA versus CIA are a reflection of the fundamental pathophysiologic differences between these 2 models of arthritis. Thus, NO production in these 2 models could not be merely a nonspecific reaction to the adjuvant injection, nor simply a byproduct of local inflammation in the joint.

Chronic Trypanosoma cruzi infection in the rat: cyclophosphamide-induced recovery of adjuvant arthritis correlates with changes in the levels of lymph node T-lymphocytes and class II+ cells

We have previously reported that treatment with cyclophosphamide (Cy) reversed the partial resistance of chronically Trypanosoma cruzi-infected rats to adjuvant-induced arthritis (AA) and caused a slight enhancement of arthritis in controls, when given 48 h before induction. To ascertain whether this Cy effect could be associated with regional changes of immunocompetent cells, popliteal lymph nodes were studied for their T-cell subsets and cells carrying class II major histocompatibility (MHC) antigens (1-A and 1-E molecules). Analysis at the time of arthritis induction revealed that infected rats receiving Cy 48 h earlier appeared to have recovered from the inverse balance of major T-cell subsets and showed 1-E+ cells lowered to normal, whereas values from control rats remained unchanged by Cy treatment. Establishment of AA was associated with substantial changes in the phenotype of lymph node cells that drained the affected limb. Changes were equally recorded in control and infected arthritic rats, and consisted of a significant raise of CD4+ and I-A+ cells along with lowered numbers of CD8+ and I-E+ cells. Treatment with Cy lowered even further the levels of CD8+ cells, while causing no affectation in the number of CD4+ cells that remained increased as in the arthritic counterparts receiving no Cy. Comparative analysis of class II MHC+ cells in Cy-treated rats revealed an additional decrease of I-E+ cells in draining lymph nodes from infected and control rats, which coincided with a simultaneous increase in I-A+ cells in the uninfected group. It is suggested that a deletion of a regulatory T-cell subset as well as an improved presentation of arthritogenic peptides may at least underlie the Cy-induced enhancement of the arthritic response.

Differential effects of methotrexate and liposomally conjugated methotrexate in rat adjuvant-induced arthritis

In this study we evaluated the comparative efficacy of free and liposomally conjugated methotrexate on both disease induction and suppression of acute inflammation in rat adjuvant-induced arthritis. Rats were given either empty liposomes (E-LIPO), free methotrexate (MTX) or the liposomally conjugated methotrexate (MTX-LIPO) at a dose of 100 micrograms/day for 7 consecutive days by the intravenous route. When MTX treatment was initiated on the day of arthritis induction the drug suppressed but did not abolish the development of joint inflammation. Free MTX had no significant anti-inflammatory effect upon an established arthritis when dosing was commenced on day 11 post-adjuvant induction. Conversely, MTX-LIPO did not affect the progression of the arthritis when dosing was started on day 0, but exerted a significant anti-inflammatory effect on an established arthritis. MTX-LIPO treatment was significantly less haematotoxic than free MTX.

Female preponderance for development of arthritis in rats is influenced by both sex chromosomes and sex steroids

Autoimmune arthritis was induced after a single injection of the non-immunogenic adjuvant (avridine) or with autologous rat type II collagen. Females of two different rat strains, DA and LEW, were found to be more susceptible than males. To investigate further the mechanisms behind the female preponderance, we selected the avridine induced arthritis model. This is known to be a chronic joint-specific disease which is T-cell dependent and associated with MHC genes and, therefore, is an appropriate model for rheumatoid arthritis. To address the possibility of sex chromosome involvement, reciprocal F1 hybrids were produced. Female (DAxLEW)F1 rats were found to be more prone to arthritis than their male counterparts. This difference could be explained, at least partly, by the influence of sex chromosomes since reciprocal (LEWxDA)F1 rats showed no sex linkage. However, the sex linkage was more pronounced in normal rats when compared to castrated (DAxLEW)F1 rats indicating a role for sex hormones in conjunction with the sex chromosome-linked effect. Both oestrogen and testosterone had a suppressive effect on the development of arthritis. The findings presented here suggest the presence of a sex chromosome gene, which mediates its function only in the presence of sex hormones and is associated with a female preponderance for development of arthritis.

Avridine-induced arthritis in rats; a T cell-dependent chronic disease influenced both by MHC genes and by non-MHC genes

Avridine is a potent synthetic adjuvant that can induce arthritis is most rat strains. The clinical appearance and histopathology of avridine-induced arthritis show great similarity to other arthritis models such as collagen-induced arthritis. In LEW and DA rats the avridine-induced arthritis is severe and long lasting. To investigate a possible genetic influence on the disease we compared LEW, DA and E3 rats, which are of different genetic origins, for their ability to develop arthritis after injection of a low dose of avridine (1.5 mg/rat). The E3 rat was shown to be resistant, whereas all of the DA rats developed arthritis. Recombinant inbred strains derived from DA and E3 parentals varied in susceptibility to avridine. Only strains sharing RT1av1 with DA developed arthritis, indicating a role for the MHC genes. The MHC association was further analysed in a series of Lewis congenic strains using the 1.5 mg avridine dose. All strains developed arthritis. LEW.1C and LEW.1W developed only acute arthritis, whereas LEW.1A, LEW, LEW.1D, LEW.1N and LEW.1F developed chronic arthritis. In particular, the LEW.1F rats developed a chronic severe arthritis of high incidence. The chronic arthritis showed an active, erosive joint inflammation several months after induction. Nude rats are resistant to avridine-induced arthritis, indicating a T cell dependence of the disease which supports the importance of MHC. However, non-MHC genes are also crucial to arthritis development. Recombinants between DA and E3, sharing RT1av1 with DA, showed either a lower incidence or a lower severity of disease than the DA rats. The E3 rat and the recombinants with RT1u were completely resistant, whereas LEW.1W, also RT1u, were highly susceptible.

Arthritis in Lewis rats induced by the non-immunogenic adjuvant CP20961: an immunohistochemical analysis of the developing disease

OBJECTIVES

The role of lymphocytes and macrophages in developing adjuvant arthritis induced by an injection of CP20961 in inbred Lewis rats was studied over a 32 day period using a novel biotin-avidin immunoperoxidase histochemical technique.

METHODS

Fresh frozen sections of hind paws and spleens, as well as lymph nodes draining the site of the injected adjuvant were immunostained using a panel of monoclonal antibodies specific for subsets of lymphocytes and macrophages and for MHC Class II antigen.

RESULTS

An increase in the numbers of activated T-lymphocytes was detected early in the draining lymph nodes before hind paw swelling had begun. The presence of these cells in significant numbers was only observed in the vicinity of the joint after joint swelling and damage had begun. Macrophages were among the first cells to invade the swollen paws and later were found with T-lymphocytes and cells bearing the MHC class II antigen at the face of eroding and re-organising bone.

CONCLUSIONS

The activity of T-lymphocytes in initiating arthritis appeared to occur early in lymph nodes. Joint destruction was more closely associated with the arrival of macrophages but later arrival of T-lymphocytes may have contributed to the maintenance of chronic inflammation.

Attenuation of adjuvant arthritis in rats by treatment with oxygen radical scavengers

The contribution of reactive oxygen species (ROS), in particular hydroxyl radical (OH.), to joint inflammation was examined in rats developing adjuvant arthritis (AA) by treatment with ROS scavengers dimethylthiourea (DMTU) and DMSO. Adjuvant arthritis was induced in Sprague-Dawley (SD) rats by a single intradermal (i.d.) injection of Mycobacterium tuberculosis (MT) in oil on day 0. By day 14, all rats exhibited arthritis in the hindlimbs and the majority had involvement of the forelimbs. A marked inflammatory cell influx (75% neutrophils) was present in the synovial fluid. These cells, in vitro, spontaneously produced OH. (0.96 +/- 0.28 OH. units/h per 10(5) cells). In contrast, spontaneous OH. production by normal circulating leucocytes was absent (0.07 +/- 0.03 OH. units/h per 10(5) cells). Adjuvant-injected rats were treated with DMTU (500, 250 and 100 mg/kg), DMSO (330 and 165 mg/kg) or saline (disease control) once daily on days 8, 9 and 10 and twice daily on days 11, 12 and 13 postadjuvant injection. Both DMTU and DMSO significantly reduced the clinical evidence of arthritis (clinical scores: DMTU [500 mg/kg] = 0, P < 0.0001; DMSO [3.0 mL/kg] = 0.4 +/- 0.3, P < 0.01, compared with disease control = 2.3 +/- 0.3). Synovial fluid cell accumulation was also significantly reduced (DMTU [500 mg+kg] = 0.5 +/- 0.1 x 10(5) cells/four joints, P < 0.0001; DMSO [3.0 mL/kg] 2.75 +/- 1.9 x 10(5) cells/four joints, P < 0.01 compared with disease control = 11.76 +/- 1.7 x 10(5) cells/four joints). Neither treatment inhibited cutaneous delayed type hypersensitivity (DTH) to the disease inducing antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acetylsalicylic acid and dexamethasone on antibody production in adjuvant arthritis

The production of antibodies to IgG and type II collagen occurs in a similar fashion in human rheumatoid arthritis and adjuvant arthritis. In this study, the effect of dexamethasone (DXT) and acetylsalicylic acid (ASA) on antibody synthesis was analysed. Daily treatment with DXT (0.3 mg/kg per day p.o.) or with ASA (200 mg/kg per day p.o.) from day 14 to day 56 after arthritis induction inhibited both the synthesis of antibodies to IgG and type II collagen and also the humoral immune response to the mycobacteria that induced the disease. The immunosuppressive response was similar for both drugs: DXT, which is known to suppress the immune response, and ASA, a classical anti-inflammatory agent.

Anti-type I collagen antibodies in advanced phases of adjuvant arthritis

The aim of this study was to elucidate the existence of autoantibodies directed to type I collagen as a response to connective tissue alterations that occur in inflammatory diseases. We have demonstrated the presence of antibodies to type I collagen during the time course of adjuvant arthritis, by means of the ELISA technique. These autoantibodies reached the highest levels in advanced phases of the arthritic process from 8 to 10 weeks after mycobacteria administration. The hind-paw swelling and the anti-type I collagen antibodies remained for at least 18 weeks post-induction.

Autoimmune recognition of cartilage collagens

Recent advances in basic research on the immune system and molecular biology of cartilage components have greatly increased our understanding of the role of autoimmunity in inflammatory diseases affecting joints, particularly rheumatoid arthritis. Many of these diseases are common and their complex pathogenesis probably involves a large number of genes polymorphic in the population as well as environmental factors. Characteristic features of inflammatory arthritis include expansion of the synovial tissue into a pannus containing lymphocytes and macrophages, autoimmune reactions against cartilage antigens, and erosion of cartilage. Since hyaline cartilage of the articular surfaces is the only structure within the joint known to contain joint-specific antigens this tissue is the prime suspect as the target of the autoimmune This review will first present the capacity of the immune system to discriminate between self and non-self structures, and then summarize our current understanding of the structures of cartilage collagens. Subsequently we will discuss how the immune system normally interacts with cartilage and how such interactions can lead to arthritis. We propose that collagen-induced arthritis (CIA) is valuable for understanding the autoimmune recognition of cartilage collagen which precedes the outbreak of arthritis and may perpetuate its chronicity, and serves as an animal model of rheumatoid arthritis.

Passive transfer of adjuvant-induced arthritis into irradiated DA recipient rats

Adjuvant-induced arthritis (AIA) can be passively transferred in Dark Agouti (DA) rats by spleen and lymph node cells after culture with Concanavalin A (Con A). A model not requiring in vitro Con A expansion and activation would be important in investigations of anti-rheumatic drugs in AIA. A new model using irradiated recipients fills this need. Donor DA rats treated with 0.1 ml complete Freund's adjuvant (CFA) containing 7.5 mg M. butyricum/ml were sacrificed 11 days after CFA injection, donor spleen cells harvested, and donor spleen cells injected intravenously into recipient DA rats previously irradiated with 5 Gy. Recipient rats developed arthritis 4-14 days after spleen cell transfer. This model can now be used to further define the effects of anti-rheumatic drugs in the passive transfer of AIA by eliminating the need for the in vitro Con A-induced expansion and/or activation of donor cells.

Disease-modifying anti-rheumatic drugs: strategies for screening

Rheumatoid arthritis, a disease of unknown aetiology, has a multifactorial pathogenesis which may result in irreversible connective tissue destruction and loss of joint function. The search for drugs which offer more than symptomatic relief is a long term, largely unachieved aim of many pharmaceutical companies. This review briefly outlines those features of the aetiopathogenesis which appear to offer targets for therapeutic intervention and the structured strategy and test systems that can be used to detect drugs which may be capable of halting disease progression.

Adjuvant arthritis pretreatment with type II collagen and Mycobacterium butyricum

A treatment previous to adjuvant arthritis induction has been performed with type II collagen (CII) or Mycobacterium butyricum (Mb), which is the inducer of the pathology. Pretreatment was administered in two different ways: a) subcutaneously or intradermally 14 days before arthritis induction, and b) intravenously 3 days before induction. In order to relate the change in inflammation to the corresponding antigen immune response, serum antibodies and delayed type hypersensitivity (DTH) against CII or Mb were studied. Pretreatment with s.c. CII 14 days before induction produced slight protection against arthritis and significantly delayed its onset; systemic inflammation showed good positive correlation with anti-CII antibodies. The CII administered i.v. 3 days before arthritic challenge did not significantly modify the inflammatory process. The use of i.d. subarthritogenic doses of Mb 14 days before induction protected a high percentage of the animals from the posterior arthritic challenge; this protection was accompanied by high anti-Mb antibody titers and DTH reaction. When Mb was given i.v. 3 days before induction, a partial protection of inflammation was observed; arthritis was milder and its onset was delayed. These changes were accompanied by reduced humoral and cellular response to Mb.

Treatment of Rheumatoid Arthritis with Single Dose or Weekly Pulses of Chimaeric Anti-CD4 Monoclonal Antibody

The aetiology of rheumatoid arthritis is unknown but CD4+ T cells are known to be involved in its pathogenesis. Because of this, anti-CD4 monoclonal antibody has been used in open studies with clinical benefit in up to 60% of patients. We have used a chimaeric anti-CD4 monoclonal antibody (cM-T412, Centocor) in a randomized, double-blinded, placebo controlled trial as treatment for rheumatoid arthritis. Nine patients with active rheumatoid arthritis resistant to traditional disease-modifying drugs were recruited. Four received an intravenous 50 mg bolus of antibody, and three received 50 mg weekly for four consecutive weeks. Two patients received placebo. Despite a marked reduction (P less than 0.001) in peripheral blood CD4+ lymphocytes, there was no significant clinical improvement in any of these patients. The decrease in CD4+ lymphocyte number lasted one week after a single 50 mg dose of cM-T412 but was more prolonged in the patients who received four infusions. CD8+ T cells, CD16+ cytotoxic cells and CD14+ monocytes showed only a transient reduction. It may be concluded that the therapeutic efficacy of anti-CD4 therapy is not directly related to CD4+ T-cell lymphopenia.

Characterisation of passively transferred antigen arthritis induced by methylated bovine serum albumin in the rat: effect of FK 506 on arthritis development

The conditions necessary for the passive transfer of antigen arthritis induced by methylated bovine serum albumin (mBSA) in the rat have been studied. Spleen cells from immunised rats were not capable of transferring disease unless they were first activated in culture with mBSA or concanavalin A. Cells from sham-immunised animals could not be activated to transfer the arthritis. The immunosuppressant drug FK 506 could inhibit the development of the arthritis when present during the activation period in culture or when dosed to the recipients of activated cells.

In vivo cyclooxygenase expression in synovial tissues of patients with rheumatoid arthritis and osteoarthritis and rats with adjuvant and streptococcal cell wall arthritis

Cyclooxygenase (COX), or prostaglandin (PG) H synthase, plays a role in inflammatory diseases, but very limited data exist on the regulation of COX in vivo. We, therefore, studied the in vivo expression of COX in synovia from patients with rheumatoid arthritis (RA) and osteoarthritis (OA), as well as joints of rats with streptococcal cell wall (SCW) and adjuvant arthritis. Extensive and intense intracellular COX immunostaining, which correlated with the extent and intensity of mononuclear cell infiltration, was observed in cells throughout RA synovia. Significantly less or equivocal staining was noted in OA and normal human synovia. Similarly, COX immunostaining was equivocal in the joints of normal and arthritis-resistant F344/N rats. In contrast, high level expression developed rapidly in euthymic female Lewis (LEW/N) rats throughout the hindlimb joints and overlying tissues including skin, preceding or paralleling clinically apparent experimental arthritis. COX was expressed in the joints of athymic LEW.rnu/rnu rats 2-4 d after injection of SCW or adjuvant but was not sustained. Physiological doses of antiinflammatory glucocorticoids, but not progesterone, suppressed both arthritis and COX expression in LEW/N rats. These observations suggest that, in vivo, (a) COX expression is upregulated in inflammatory joint diseases, (b) the level of expression is genetically controlled and is a biochemical correlate of disease severity, (c) sustained high level up-regulation is T cell dependent, and (d) expression is down-regulated by antiinflammatory glucocorticoids.