Histopathology of arthritis induced in rats by active immunization to mycobacterial antigens or by systemic transfer of T lymphocyte lines. A light and electron microscopic study of the articular surface using cationized ferritin

Hyperbilirubinemia Maintained by Chronic Supplementation of Unconjugated Bilirubin Improves the Clinical Course of Experimental Autoimmune Arthritis

Rheumatoid arthritis (RA) is a chronic multisystem disease, therapy of which remains a challenge for basic research. The present work examined the effect of unconjugated bilirubin (UCB) administration in adjuvant-induced arthritis (AIA)—an experimental model, in which oxidative stress (OS), inflammation and inadequate immune response are often similar to RA. Male Lewis rats were randomized into groups: CO—control, AIA—untreated adjuvant-induced arthritis, AIA-BIL—adjuvant-induced arthritis administrated UCB, CO-BIL—control with administrated UCB. UCB was administered intraperitoneally 200 mg/kg of body weight daily from 14th day of the experiment, when clinical signs of the disease are fully manifested, to 28th day, the end of the experiment. AIA was induced by a single intradermal immunization at the base of the tail with suspension of Mycobacterium butyricum in incomplete Freund’s adjuvant. Clinical, hematologic, biochemical and histologic examinations were performed. UCB administration to animals with AIA lead to a significant decrease in hind paws volume, plasma levels of C-reactive protein (CRP) and ceruloplasmin, drop of leukocytes, lymphocytes, erythrocytes, hemoglobin and an increase in platelet count. UCB administration caused significantly lowered oxidative damage to DNA in arthritic animals, whereas in healthy controls it induced considerable oxidative damage to DNA. UCB administration also induced atrophy of the spleen and thymus in AIA and CO animals comparing to untreated animals. Histological signs of joint damage assessed by neutrophils infiltration and deposition of fibrin were significantly reduced by UCB administration. The effects of exogenously administered UCB to the animals with adjuvant-induced arthritis might be identified as therapeutic, in contrast to the effects of UCB administration in healthy animals rather classified as toxic.

Tofacitinib attenuates arthritis manifestations and reduces the pathogenic CD4 T cells in adjuvant arthritis rats

Rheumatoid arthritis (RA) is an autoimmune disease characterized by pronounced inflammation and leukocyte infiltration in affected joints. Tofacitinib is new agent, a selective inhibitor of Janus kinase (JAK) signaling pathways mediated by JAK1 and JAK3 and inhibits the key transcription factors STAT1 and STAT3. We investigated the action mechanisms of tofacitinib in rats with adjuvant-induced-arthritis (AIA). AIA-rats were treated orally with tofacitinib or with methotrexate. Arthritis severity and serum C-reactive protein (CRP) levels were evaluated, splenic cells were examined by flow cytometry and cytokines were analyzed by real-time PCR. Tofacitinib markedly reduced the clinical status of treated rats in comparison to control group. Reduced joints inflammation and down-regulated serum CRP levels reflected the clinical manifestations of the treated rats. Tofacitinib down-regulated significantly the frequency of CD4⁺IFN-γ⁺ T cells and reduced IL-1β mRNA expression levels in the spleen of the treated rats. These results show that tofacitinib attenuated arthritis severity, modified splenic populations and cytokine imbalance.

Identification and functional characterization of T cells reactive to citrullinated vimentin in HLA-DRB1*0401-positive humanized mice and rheumatoid arthritis patients

OBJECTIVE

Antibodies toward the citrullinated form of the synovial antigen vimentin are specific for rheumatoid arthritis (RA) and are associated with HLA-DRB1*0401. This suggests that T cells specific for peptides derived from citrullinated vimentin presented in the context of HLA-DRB1*0401 may contribute to the etiopathogenesis of RA. The aim of this study was to identify immunodominant epitopes from citrullinated vimentin presented by HLA-DRB1*0401 and to characterize the resulting T cell responses.

METHODS

We first predicted an HLA-binding T cell epitope from citrullinated vimentin based on the binding motif of HLA-DRB1*0401 and then confirmed its affinity. A class II major histocompatibility complex (MHC) tetramer loaded with the citrullinated form of vimentin aa 59-78 (cit-vimentin aa 59-78) was constructed and used to screen for specific T cells in HLA-DRB1*0401-transgenic mice, patients with RA, and healthy control subjects. Additionally, the cytokine output following cit-vimentin aa 59-78 challenge was analyzed in patients and healthy control subjects by multicolor flow cytometry and Luminex-based analysis.

RESULTS

The citrullinated form of vimentin aa 59-78 bound to HLA-DRB1*0401, but the native form could not. Subsequently, cit-vimentin aa 59-78-specific T cells were detected in immunized mice and in the periphery of both HLA-DR*0401-positive healthy control subjects and HLA-DR*0401-positive patients with RA, using class II MHC tetramers, CD154 up-regulation, and intracellular cytokine measurements. As demonstrated in cell culture supernatants, the production of cytokines (predominantly interferon-γ) in response to cit-vimentin aa 59-78 was significantly higher in patients compared with controls.

CONCLUSION

Here, we describe a posttranslational modification of an RA candidate autoantigen toward which HLA-DRB1*0401-restricted T cells can be detected in both patients with RA and healthy controls but for which a proinflammatory response is observed uniquely in patients with RA.

Recruitment of dendritic cells and macrophages during T cell-mediated synovial inflammation

Adoptive transfer of adjuvant-induced arthritis was used in this study to examine local macrophages and dendritic cells (DCs) during T cell-mediated synovial inflammation. We studied the influx of CD11b⁺CD11c⁺ putative myeloid DCs and other non-lymphoid CD45⁺ cells into synovium-rich tissues (SRTs) of the affected hind paws in response to a pulse of autoreactive thoracic duct cells. Cells were prepared from the SRTs using a collagenase perfusion-digestion technique, thus allowing enumeration and phenotypic analysis by flow cytometry. Numbers of CD45⁺ cells increased during the first 6 days, with increases in CD45⁺MHC (major histocompatibility complex) II⁺ monocyte-like cells from as early as day 3 after transfer. In contrast, typical MHC II^- monocytes, mainly of the CD4^- subset, did not increase until 12 to 14 days after cell transfer, coinciding with the main influx of polymorphonuclear cells. By day 14, CD45⁺MHC II^hi cells constituted approximately half of all CD45⁺ cells in SRT. Most of the MHC II^hi cells expressed CD11c and CD11b and represented putative myeloid DCs, whereas only approximately 20% were CD163⁺ macrophages. Less than 5% of the MHC II^hi cells in inflamed SRT were CD11b^-, setting a maximum for any influx of plasmacytoid DCs. Of the putative myeloid DCs, a third expressed CD4 and both the CD4⁺ and the CD4^- subsets expressed the co-stimulatory molecule CD172a. Early accumulation of MHC II^hiCD11c⁺ monocyte-like cells during the early phase of T cell-mediated inflammation, relative to typical MHC II^- blood monocytes, suggests that recruited monocytes differentiate rapidly toward the DC lineage at this stage in the disease process. However, it is possible also that the MHC II^hiCD11c⁺ cells originate from a specific subset of DC-like circulating mononuclear cells.

Glomerular expression of neuronal activity-regulated pentraxin precedes the development of anti-Thy-1-induced progressive glomerulosclerosis

Although it is clear that genetic predispositions play a role in progressive glomerulosclerosis, identification of specific genes is difficult because of natural genetic heterogeneity among individuals. We have reported a differential susceptibility to progressive glomerulosclerosis after induction of experimental glomerulonephritis anti-Thy-1 nephritis in Lewis rat substrains. Glomerular lesions in Lewis/Møllegard rats resolve spontaneously, whereas Lewis/Maastricht (Lew/Maa) rats develop progressive glomerulosclerosis. This predisposition for progressive glomerulosclerosis is governed by unknown genes that are expressed by renal cells. Here, differential gene expression analysis using a rat complementary DNA micro array revealed neuronal activity-regulated pentraxin (Narp) as a candidate gene involved in the remodeling or progression of damaged glomeruli. Glomerular Narp mRNA expression was monitored during disease in both Lewis sub strains. Immunohistochemistry revealed that Narp protein is exclusively expressed in Lew/Maa glomeruli 7 and 14 days after induction of anti-Thy-1 nephritis. Double-immunofluorescent staining showed that proliferating mesangial cells and parietal epithelial cells (PECs) at sites of adhesion to podocytes are partially Narp-positive, whereas podocytes fail to express Narp. Immunohistochemistry in nephritic Wistar, unilaterally nephrectomized Wistar and Sprague-Dawley rats showed that Narp protein is present only in strains that develop progressive glomerulosclerosis but never in strains that show remodeling. We conclude that Narp is a predictor for anti-Thy-1 nephritis-induced glomerulosclerosis and its expression by PECs may be involved in the progression to glomerulosclerosis.

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.

Lactobacillus GG bacteria ameliorate arthritis in Lewis rats

Probiotic bacteria have beneficial effects in infectious and inflammatory diseases, principally in bowel disorders. In the case of chronic progressive autoimmune arthritides, a major goal of treatment is to reduce inflammation. We hypothesized that probiotic bacteria would ameliorate inflammation found in arthritis models. To assess this effect, Lewis rats were injected with 50 microg bovine alpha-tropomyosin (TRM) or complete Freund's adjuvant (CFA) to induce tropomyosin arthritis (TA) or adjuvant arthritis (AA), respectively. In both models, the rats were divided into 6 groups and fed 0.5 mL/d of the following suspensions: 1) heat-killed Lactobacillus GG (LGG) bacteria; 2) live LGG, both 10(11) colony-forming units (cfu)/L; 3) sterilized milk; 4) plain yogurt; 5) yogurt containing 10(11) cfu/L LGG; or 6) sterilized water. In the disease-prevention experiments, feeding started 1 wk before or after disease induction. In the therapeutic experiments, feeding was initiated at the onset of clinical arthritis. In all experiments, there were significant interactions between time and treatment (P < 0.001), except for milk, which had no effect in the therapeutic experiment. Histologically, rats fed yogurt containing LGG had a milder inflammation in all experiments (P < 0.05), whereas rats fed plain yogurt exhibited a moderate inflammatory score only in the prevention experiments. Anti-TRM antibody titers were not affected by any of the treatments in any of the experiments. Ingestion of live or heat-killed human LGG had a clinically beneficial effect on experimental arthritis. Our observation of the remarkable preventive and curative effect on arthritis using commercial yogurts containing lactobacilli, especially LGG, suggests the need for investigation of these agents in arthritic patients.

A new spin on an old model: in vivo evaluation of disease progression by magnetic resonance imaging with respect to standard inflammatory parameters and histopathology in the adjuvant arthritic rat

OBJECTIVE

To noninvasively examine the pathogenesis of rat adjuvant-induced arthritis (AIA) by magnetic resonance imaging (MRI), and to correlate MRI indices of disease progression with classic inflammatory parameters and histologic evaluation.

METHODS

AIA was established in male Lewis rats following subcutaneous injection in the right hindpaw with 0.5 mg of heat-killed Mycobacterium butyricum suspended in light mineral oil. In vivo MRI evaluations of soft tissue and bony changes in AIA rats with matched histopathology were correlated with changes in left hindpaw volumes, circulating leukocytes, acute-phase reactants, and urinary collagen crosslinks throughout the disease process.

RESULTS

MRI of arthritic tibiotarsal joints of the uninjected left hindpaws from AIA rats demonstrated 2 distinct phases of disease activity. The first phase, apparent between days 10 and 18, was characterized by periarticular inflammation with marked synovitis, synovial fibroplasia, and distension of the joint capsule into the surrounding tissue. The secondary phase, occurring between days 18 and 30, was marked by continued soft tissue inflammation, periostitis with osteolysis, and periosteal new bone formation progressing to a state of near complete ankylosis by day 30. These 2 phases of disease activity observed by MRI paralleled biochemical, cellular, and histologic markers of disease progression.

CONCLUSION

MRI can be used to noninvasively detect, monitor, and quantify the chronic synovitis and progressive destruction of soft tissue and bone in live AIA rats, thereby improving the ability to evaluate disease progression in this preclinical animal model of rheumatoid arthritis.

Pathogenicity of cilia-associated respiratory (CAR) bacillus isolates for F344, LEW, and SD rats

We conducted experiments to test whether rats of F344, LEW, and SD strains differ in susceptibility to mycoplasma-free isolates of cilia-associated respiratory (CAR) bacillus, whether Mycoplasma pulmonis can affect expression of CAR bacillus disease, and whether isolates of CAR bacillus differ in virulence for rats. In the first experiment, 24 rats of each strain were inoculated intranasally with 10(7) bacilli of CAR bacillus X1428D/AS, and 24 rats of each strain were inoculated with sterile medium (controls). Eight weeks later, eight inoculated rats and eight control rats of each strain were euthanatized, eight inoculated and eight control rats were given 10(6.5) colony-forming units of M. pulmonis X1428D, and eight inoculated rats and eight control rats were sham inoculated. Four rats of each group were euthanatized 4 or 8 weeks after the second inoculation. Severity of lesions in nasal passages, middle ear, trachea, and lungs was assessed by scoring. Rats of all three strains given CAR bacillus had typical lesions of similar severity; M. pulmonis X1428D was avirulent and did not exacerbate CAR bacillus disease. In the second experiment, groups of eight rats of F344 and SD strains were given 10(5) or 10(7) CAR bacillus X1328E, X1428D/AS, or X2450D and euthanatized 8 or 16 weeks later. Isolates X1428D/AS and X2450D caused similar lesions in rats of both strains and at both doses, but CAR bacillus X1328E was avirulent. Rats of the tested strains are similarly susceptible to CAR bacillus disease, but CAR bacillus isolates differ in virulence.

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.

Comparative severity of respiratory lesions of sialodacryoadenitis virus and Sendai virus infections in LEW and F344 rats

In several chronic diseases, lesions are more severe in LEW rats than in F344 rats. To determine whether or not acute viral diseases also are more severe in LEW rats than in F344 rats, we inoculated 6-7-week-old LEW and F344 rats with 10(7.2) cell culture infective units of sialodacryoadenitis virus or 10(4.7) infective units of Sendai virus. Twenty-four rats of each strain were given each virus. Lesions in nasal passages, tracheas, intrapulmonary airways, and pulmonary alveoli in 6 or 12 rats inoculated with each virus were assessed by scoring 5, 10, and 14 days after inoculation. Both viruses caused typical patchy necrotizing rhinitis, tracheitis, bronchitis, and bronchiolitis, with multifocal pneumonitis, in rats of both strains. Mean lesion indices for LEW rats given sialodacryoadenitis virus were significantly different from those for F344 rats for nasal passages on days 10 (0.999 vs. 0.680) and 14 (0.736 vs. 0.278), bronchi on day 5 (0.479 vs. 0.361), and alveoli on day 5 (0.677 vs. 0.275). Lesion indices for LEW rats given Sendai virus were significantly different from those for F344 rats for nasal passages on days 10 (1.000 vs. 0.611) and 14 (0.778 vs. 0.583); trachea on day 10 (0.625 vs. 0.028); bronchi on days 5 (0.476 vs. 0.331), 10 (0.123 vs. 0.013), and 14 (0.038 vs. 0); and alveoli on days 5 (0.413 vs. 0.114) and 10 (0.185 vs. 0.020). Thus, at the tested doses, both viruses caused more severe respiratory tract lesions in LEW rats than in F344 rats.

Suppression of chronic antigen-induced arthritis in rats by a monoclonal antibody against the T cell receptor alpha beta

We have investigated a role for T cells in chronic antigen-induced arthritis in rats employing a monoclonal antibody (R73 mAb) against the T cell receptor alpha beta. Treatment with R73 mAb from the time of intra-articular antigenic challenge blocked completely the induction of chronic, but not acute ovalbumin-induced arthritis in sensitized rats. Histologically, treatment-controlled arthritic rats exhibited marked hyperplasia of synovial membrane with pronounced infiltration of inflammatory cells including alpha beta + T cells in the chronic phase of arthritis. In contrast, R73 mAb-treated rats had almost normal joint histology. Treatment with R73 mAb after onset of arthritis was also effective in suppressing the progression of chronic antigen-induced joint inflammation. The preventive and suppressive effects of the mAb on chronic antigen-induced arthritis were associated with marked depletion of alpha beta + T cells in peripheral blood. The DTH but not the humoral response to ovalbumin in sensitized rats was suppressed significantly by R73 mAb. Thus, alpha beta + T cells appear to have a central role in both induction and progression of chronic antigen-induced arthritis.

Immunohistology of joint inflammation induced in rats by cell wall fragments of Eubacterium aerofaciens

After a single intraperitoneal injection of cell wall fragments of Eubacterium aerofaciens, a main resident from the human intestinal flora, an acute arthritis develops within 2 days which is followed by a chronic arthritis that lasts at least 90 days. In an earlier report the histological appearance of the joint inflammation during this period has been described. In this study we investigated in more detail the cell types that are involved in the development of arthritis by using cell-type-specific monoclonal antibodies in an immunohistological assay. In the acute phase of arthritis, T-helper cells appeared in the synovial tissue together with ED1-positive (ED1+) and ED3-positive (ED3+) macrophages. After a temporary decline at day 12 all macrophage subsets, as well as T-helper cells, reappeared or increased again at day 33. Later, in the chronic phase (days 47-90), an increased number of ED1-positive (ED1+) cells in the synovial tissue and a decreased number of ED2-positive (ED2+) cells in the synovial lining was the most prominent finding when compared with control rats. These results indicate that, apart from T lymphocytes, macrophages also play an important role in the development and continuation of chronic arthritis in this model.

Changes of immunoregulatory properties and induction of autoimmune reactivity to cartilage in rabbits with antigen-induced arthritis

The chronicity of the antigen-induced arthritis is characterized as dependent on the development of cell-mediated immunity to the antigen, but the exact mechanisms underlying are unclear. We have evidenced decreased suppressor and increased helper cell potential in the early phase of arthritis as result of the immunization procedure. In the late phase of arthritis proliferative responses of spleen lymphocytes to cartilage proteoglycans were revealed which were neither present in immunized animals without arthritis induction nor in the early phase of arthritis. The changes of the regulatory properties on the T-cell level are probably responsible for the transition of acute arthritis into the chronic stage. The deficiency of an effective suppression and/or the increased helper cell potential results in the activation of B- and T-lymphocytes with increased cell-mediated and humoral immune responsiveness to the antigen maintaining the inflammatory process for a long time. In this situation the release of cartilage proteoglycans during the acute joint reaction induces autoimmune responses against cartilage which could contribute to the chronification of inflammation and to cartilage degradation.

Regression of adjuvant-induced arthritis in rats following bone marrow transplantation

Total body irradiation followed by bone marrow transplantation was found to be an effective treatment for adjuvant arthritis induced in rats. This treatment is most effective when applied shortly after the clinical manifestation of arthritis--i.e., 4-7 weeks after administration of Mycobacterium tuberculosis. Transplantation of bone marrow at a later stage results in a limited recovery, in that the inflammatory reaction regresses but the newly formed excessive bone is not eliminated. Local irradiation of the affected joints had no effect on the disease. It could also be excluded that the recovery of arthritis following marrow transplantation is due to lack of available antigen. Transplantation of syngeneic bone marrow is as effective as that of allogeneic bone marrow from a rat strain that is not susceptible to induction of adjuvant arthritis. The beneficial effect of this treatment cannot be ascribed to the immunosuppressive effect of total body irradiation, since treatment with the highly immunosuppressive drug Cyclosporin A resulted in a regression of the joint swelling but relapse occurred shortly after discontinuation of the treatment.

Arthritis associated with adjuvant mycobacterial treatment for carcinoma of the bladder

A patient who developed an inflammatory polyarthritis following intravesical administration of bacillus Calmette-Guérin (BCG) used in the treatment of bladder cancer is described. An inflammatory synovitis comprising predominantly T lymphocytes was demonstrated on synovial biopsy. The synovitis resolved spontaneously within 14 days in this 'human model' of adjuvant arthritis.

Suppression of experimental autoimmune diseases and prolongation of allograft survival by treatment of animals with low doses of heparins

The ability of activated T lymphocytes to penetrate the extracellular matrix and migrate to target tissues was found to be related to expression of a heparanase enzyme (Naparstek, Y., I. R. Cohen, Z. Fuks, and I. Vlodavsky. 1984. Nature (Lond.). 310:241-243; Savion, N., Z. Fuks, and I. Vlodavsky. 1984. J. Cell. Physiol. 118:169-176; Fridman, R., O. Lider, Y. Naparstek, Z. Fuks, I. Vlodavsky, and I. R. Cohen. 1987. J. Cell. Physiol. 130:85-92; Lider, O., J. Mekori, I. Vlodavsky, E. Baharav, Y. Naparstek, and I. R. Cohen, manuscript submitted for publication). We found previously that heparin molecules inhibited expression of T lymphocyte heparanase activity in vitro and in vivo, and administration of a low dose of heparin in mice inhibited lymphocyte traffic and delayed-type hypersensitivity reactions (Lider, O., J. Mekori, I. Vlodavsky, E. Baharav, Y. Naparstek, and I. R. Cohen, manuscript submitted for publication). We now report that treatment with commercial or chemically modified heparins at relatively low doses once daily (5 micrograms for mice and 20 micrograms for rats) led to inhibition of allograft rejection and the experimental autoimmune diseases adjuvant arthritis and experimental autoimmune encephalomyelitis. Higher doses of the heparins were less effective. The ability of chemically modified heparins to inhibit these immune reactions was associated with their ability to inhibit expression of T lymphocyte heparanase. There was no relationship to anticoagulant activity. Thus heparins devoid of anticoagulant activity can be effective in regulating immune reactions when used at appropriate doses.