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Various rodent models of arthritis are essential to dissect the full complexity of human rheumatoid arthritis ( RA), a common autoimmune disease affecting joints. The SKG model of arthritis originates from a spontaneous mutation in ZAP-70 found in a BALB/c colony. This mutation affects T cell selection due to reduced TCR signalling, which allows leakage of self-reactive T cells from the thymus. To further expand the practical applicability of this unique model in arthritis research, we investigated the arthritogenicity of the SKG mutation in two common black mouse strains C57 BL/6.Q and C57 BL/10.Q and compared to BALB/c.Q. Mice retained the reduced TCR signalling characteristic of SKG. BALB/c mice, which leads to similar alteration in thymic selection. Importantly, mice also retained susceptibility to chronic arthritis after a single injection of mannan from Saccharomyces cerevisiae, with comparable prevalence and severity regardless of the genetic background. Further characterization of CD4+ T cells revealed a similar bias towards IL-17 production and activated T cell phenotype in all SKG strains compared to respective wild type controls. Finally, transfer of SKG thymocytes conferred susceptibility to recipients, which confirm the intrinsic defect and pathogenicity of T cells. Overall, these results underline the strong impact that the W163C ZAP-70 mutation has on T cell-driven arthritis, and they support the use of the SKG model in black mice, which is useful for further investigations of this distinctive arthritis model to better understand autoimmunity. [ABSTRACT FROM AUTHOR]

Collagen-induced arthritis (CIA) is a well studied mouse model of the human disease rheumatoid arthritis (RA). Both CIA and RA are complex diseases affected by multiple genes as well as environmental factors. Identifying the genes that determine susceptibility to arthritis would give invaluable clues to the largely unknown aetiology of RA. In this study, we dissected a known locus, Cia6, as well as a genomic region on chromosome 14 with no previously known arthritis loci, using a partial advanced intercross and a collection of congenic strains. The chromosome 14 congenic fragment, containing the T-cell receptor alpha ( Tcra) locus, was included based on the hypothesis that the Cia6 locus is caused by a polymorphism in the Tcr beta ( Tcrb) locus and that the two loci interact. Splitting up the congenic fragments revealed multiple loci affecting arthritis traits as well as production of collagen-specific autoantibodies. In total seven new loci were identified of which four were in the previously unlinked chromosome 14 region. Both Tcr loci were within CIA loci making them candidate susceptibility genes. The results demonstrate the importance of breaking up genetic regions in smaller fragments to identify the underlying complex set of loci. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To develop a new mouse model for arthritis using cartilage oligomeric matrix protein (COMP) and to study the role of major histocompatibility complex (MHC) and Ncf1 genes in COMP-induced arthritis (COMPIA). METHODS: Native (pentameric) and denatured (monomeric) COMP purified from a rat chondrosarcoma was injected into mice with Freund's adjuvant to induce arthritis. C3H.NB, C3H.Q, B10.P, B10.Q, (B10.Q x DBA/1)F1, (BALB/c x B10.Q)F1, Ncf1 mutated, H-2Aq, H-2Ap, and human DR4+-transgenic mice were used. Anti-COMP antibodies and COMP levels in the immune sera were analyzed, and passive transfer of arthritis with purified immune sera was tested. RESULTS: Immunization with rat COMP induced a severe, chronic, relapsing arthritis, with a female preponderance, in the mice. The disease developed in C3H.NB mice, but not in B10.P mice, although they share the same MHC haplotype. Both H-2q and H-2p MHC haplotypes allowed the initiation of COMPIA. Using H-2Aq-transgenic and H-2Ap-transgenic mice, we demonstrated a role of both the Aq and Ep class II molecules in this model. Interestingly, the introduction of a mutation in the Ncf1 gene, which is responsible for the reduced oxidative burst phenotype, into the COMPIA-resistant B10.Q mouse strain rendered them highly susceptible to arthritis. In addition, the transfer of anti-COMP serum was found to induce arthritis in naive mice. Mice transgenic for the rheumatoid arthritis (RA)-associated DR4 molecule were found to be highly susceptible to COMPIA. CONCLUSION: Using rat COMP, we have developed a new and unique mouse model of chronic arthritis that resembles RA. This model will be useful as an appropriate and alternative model for studying the pathogenesis of RA. [ABSTRACT FROM AUTHOR]

Oestrogen is not only a sex hormone but also an important regulator of the immune system. Expression of the heavy chain of IgM (μ) is essential for B-cell differentiation. However, a small number of IgA-positive B cells can be found in mice lacking the μ chain (μMT−/−). The aim of this study was to investigate the effects of oestrogen on this alternative B-cell pathway in μMT−/− mice. Our results clearly demonstrate that oestrogen increases the frequency of IgA-producing B cells in μMT−/− mice in both bone marrow and spleen cells. We also show that mature IgM-producing B cells are not required for oestrogen-mediated suppression of granulocyte-mediated inflammation or thymic involution. In conclusion, we demonstrate that 17β-estradiol benzoate increases the frequency of IgA-producing B cells in μMT−/− mice, suggesting that oestrogen can influence the alternative B-cell pathway found in μMT−/− mice. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Type II collagen (CII) is a candidate autoantigen implicated in the pathogenesis of rheumatoid arthritis (RA). Posttranslational glycosylation of CII could alter intracellular antigen processing, leading to the development of autoimmune T cell responses. To address this possibility, we studied the intracellular processing of CII for presentation of the arthritogenic glycosylated epitope CII(259-273) to CD4 T cells in macrophages from HLA-DR1-transgenic mice. METHODS: HLA-DR1-transgenic mice were generated on a class II major histocompatibility complex-deficient background, and T cell hybridomas specific for the glycosylated and nonglycosylated epitope CII(259-273) were developed. Subcellular fractionation of macrophages was used to localize CII degradation to particular compartments and to identify the catalytic subtype of proteinases involved. RESULTS: We showed that the glycosylated CII(259-273) epitope required more extensive processing than did the nonglycosylated form of the same epitope. Dense fractions containing lysosomes were primarily engaged in the processing of CII for antigen presentation, since these compartments contained 1) enzyme activity that generated antigenic CII fragments bearing the arthritogenic glycosylated epitope, 2) the antigenic CII fragments themselves, 3) CII peptide-receptive HLA-DR1 molecules, and 4) peptide/HLA-DR1 complexes that could directly activate T cell hybridomas. Degradation of CII by dense fractions occurred optimally at pH 4.5 and was abrogated by inhibitors of serine and cysteine proteinases. CONCLUSION: Processing of the arthritogenic glycosylated CII(259-273) epitope, which is implicated in the induction of autoimmune arthritis, is more stringently regulated than is processing of the nonglycosylated form of the same epitope. Mechanisms of intracellular processing of the glycosylated epitope may constitute novel therapeutic targets for the treatment of RA. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To analyze the genetic impact of allelic variants of the protein tyrosine phosphatase N22 (PTPN22) and HLA-DRB1 alleles on IgG autoantibody formation directed toward an immunodominant conformational epitope (C1(III); amino acid residues 359-369) of type II collagen (CII) in early rheumatoid arthritis (RA). METHODS: Sera obtained at study inclusion from an inception cohort of RA patients (n = 221; mean symptom duration 6 months) were analyzed for circulating anti-C1(III) IgG autoantibodies. An enzyme-linked immunosorbent assay based on solid-phase-coupled synthetic triple-helical collagen peptides was used to quantify humoral autoimmune responses. HLA-DRB1 genotypes were determined by allele-specific polymerase chain reaction amplification of genomic DNA and sequence-specific hybridization. PTPN22*620W genotyping was performed using an allelic discrimination TaqMan assay. RESULTS: Anti-C1(III) IgG autoantibody titers were significantly elevated in patients with early RA as compared with those in healthy controls (n = 70). The increased titers were more pronounced in RA patients harboring alleles of the RA-associated HLA-DRB1 shared epitope (SE) consensus sequence than in those lacking the SE. In addition, the PTPN22*620W variant was strongly associated with a vigorous humoral autoimmune response to the cartilage-specific CII determinant C1(III). CONCLUSION: Allelic variants encoding the binding pocket for peptide presentation (SE) to T cells and a functional domain of a negative regulator of T cell receptor signaling (PTPN22*620W), respectively, synergize in early RA to break self tolerance toward C1(III), an evolutionarily conserved cartilage determinant that is also frequently targeted in arthritogenic humoral autoimmunity in mice. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Clinical trials using interferon-beta (IFNbeta) in the treatment of rheumatoid arthritis have shown conflicting results. We undertook this study to understand the mechanisms of IFNbeta in arthritis at a physiologic level. METHODS: Collagen-induced arthritis (CIA) was induced in IFNbeta-deficient and control mice. The role of IFNbeta was investigated in both the priming and effector phases of the disease. The effect of IFNbeta deficiency on synovial cells, macrophages, and fibroblasts from preimmunized mice was analyzed by flow cytometry, immunohistochemistry, and enzyme-linked immunosorbent assay. Differences in osteoclast maturation were determined in situ by histology of arthritic and naive paws and by in vitro maturation studies of naive bone marrow cells. The importance of IFNbeta-producing fibroblasts was determined by transferring fibroblasts into mice at the time of CIA immunization. RESULTS: Mice lacking IFNbeta had a prolonged disease with a higher incidence compared with control mice. IFNbeta deficiency was found to influence the effector phase, but not the priming phase, of arthritis. Compared with control mice, IFNbeta-deficient mice had greater infiltration of CD11b+ cells and greater production of tumor necrosis factor alpha in vivo, and their macrophages and fibroblasts were both more activated in vitro. Moreover, IFNbeta-deficient mice generated a greater number of osteoclasts in vitro, and mice immunized to induce arthritis, but not naive mice, had a greater number of osteoclasts in vivo compared with control mice. Importantly, IFNbeta-competent fibroblasts were able to ameliorate arthritis in IFNbeta-deficient recipients. CONCLUSION: Our data indicate that IFNbeta is involved in regulating the activation state of osteoclasts and stromal cells, including macrophages and fibroblasts, but that it has little effect on T cells. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the contrasting roles of plasminogen deficiency between models of collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA). METHODS: We developed a new animal model of arthritis, which we have called local injection-induced arthritis (LIA). In this model, we replaced methylated bovine serum albumin, which is normally used as an immunogen and is injected intraarticularly into the knee joint, with type II collagen (CII) to induce AIA. The severity of CIA, LIA, and AIA in wild-type and plasminogen-deficient mice was evaluated by clinical scoring or histologic grading. Necrosis was determined by histology and immunohistochemistry. RESULTS: After CII immunization alone, wild-type mice developed arthritis in most of the paws as well as in the knee joints, whereas plasminogen-deficient mice were totally resistant to the disease. Local knee injections of CII or saline slightly enhanced the severity of the knee arthritis in wild-type mice during a 60-day experimental period. Unexpectedly, the plasminogen-deficient mice also developed arthritis in joints that were injected with CII or saline. However, the arthritis was milder than that in their wild-type littermates. Sustained tissue necrosis was found only in the plasminogen-deficient mice after the local injection. CONCLUSION: Our data show that both the antigen and the joint trauma caused by the local injection are critical to explaining the contrasting roles of plasminogen deficiency in CIA and AIA. This further indicates that CIA and AIA have distinct pathogenic mechanisms. The data also suggest that plasmin may be required for the induction of these arthritis models that are critically dependent on complement activation. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Some monoclonal antibodies (mAb) to type II collagen (CII) are arthritogenic upon passive transfer to mice. We undertook this study to investigate whether such mAb are pathogenic in the absence of mediators of inflammation. METHODS: The arthritogenic mAb CIIC1 and M2139, and the nonarthritogenic mAb CIIF4, each reactive with a distinct and well-defined conformational epitope on CII, were compared with control mAb GAD6. Bovine chondrocytes were cultured with one of the mAb, and on days 3, 6, and 9, antibody binding by chondrocytes and newly synthesized extracellular matrix (ECM) was examined by immunofluorescence, morphologic effects were studied by electron microscopy, and synthesis of matrix components was determined by metabolic labeling with (3)H-proline for collagen and (35)S-sulfate for proteoglycans. RESULTS: All 3 mAb to CII bound to the matrix. CIIC1 and M2139 adversely affected the cultures, whereas CIIF4 did not. CIIC1 caused disorganization of CII fibrils in the ECM without affecting chondrocyte morphology, and increased matrix synthesis. M2139 caused thickening and aggregation of CII fibrils in the ECM and abnormal chondrocyte morphology but matrix synthesis was unaffected. CONCLUSION: The unique arthritogenic capacity of particular anti-CII mAb upon passive transfer could be explained by their adverse, albeit differing, effects in primary cultures of chondrocytes. Such effects occur independent of inflammation mediators and are related to the epitope specificity of the mAb. Interference with the structural integrity of CII could precede, and even initiate, the inflammatory expression of disease. [ABSTRACT FROM AUTHOR]

We investigated the role of the major histocompatibility complex (MHC) region in the specificity of autoimmunity by analysing specifically the development of sialadenitis, but also insulitis, nephritis and autoantibody production in autoimmune-prone nonobese diabetic (NOD) mice where the MHC H2g7 haplotype had been exchanged for the H2q (NOD.Q) or H2p (NOD.P) haplotype. The exchange of H2 haplotype did not affect the frequency of sialadenitis because the H2q and H2p congenic NOD strains developed sialadenitis with the same incidence as NOD. However, the severity of sialadenitis varied among the strains, as NOD.Q > NOD > NOD.P. At 11–13 weeks of age, the NOD.Q (H2q) female mice developed more severe sialadenitis compared to NOD.P (H2p) (P = 0.038). At 20 weeks, the NOD (H2g7) female mice showed more severe sialadenitis than NOD.P (P = 0.049). This is in contrast to the development of insulitis in the present strains, because the incidence of insulitis was almost completely inhibited by the replacement of the H2g7 haplotype of NOD. The incidence of insulitis in NOD.Q was 11–22%, compared to 75% in NOD, which correlated well with lower titres of anti-glutamic acid decarboxylase (anti-GAD) antibodies in NOD.Q compared to NOD (P = 0.009). However, the introduction of the H2q haplotype into the NOD strain instead directed the autoimmune response towards the production of lupus types of autoantibodies, because the incidence of antinuclear antibodies (ANA) in NOD.Q was 89% compared with 11% in NOD.P and 12% in NOD mice, which in turn correlated with a high incidence of nephritis in NOD.Q compared to NOD. Consequently, we show that different haplotypes of MHC are instrumental in directing the specificity of the spontaneous autoimmune inflammation. [ABSTRACT FROM AUTHOR]

Rostrom B, Grubb A, Holmdahl R. Oligoclonal IgG bands synthesized in the central nervous system are present in rats with experimental autoimmune encephalomyelitis. Acta Neurol Scand 2003 DOI: 10.1046/j.1600-0404.2003.00187.x © Blackwell Munksgaard 2003. Oligoclonal bands (OBs) in electrophoresis of cerebrospinal fluid (CSF) are present in multiple sclerosis and here is investigated whether these also occur in experimental autoimmune encephalomyelitis (EAE). Experimental autoimmune encephalomyelitis was induced in 42 DA rats after immunization with rat spinal chord homogenate and the occurrence of OBs were detected by electrophoresis of both sera and CSF. The relationship between disease symptoms, antibody response against myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG) and appearance of OBs was studied. Development of CSF-specific OB was found to occur, 6 weeks after immunization, in seven of 42 rats. OB was detected in rats with an antibody response against MBP, whereas as a role no such bands were present in rats with an antibody response against MOG. Initially severe disease symptoms were correlated to a concomitant intense oligoclonal antibody response. Cerebrospinal fluid-specific OB occurs in EAE. It is present in rats with an anti-MBP, but not in rats with an anti-MOG antibody response. A severe disease results in an intense oligoclonal antibody response, which might have an anti-inflammatory effect. [ABSTRACT FROM AUTHOR]

Abstract Positional cloning of susceptibility genes in complex diseases like rheumatoid arthritis in humans is hampered by aspects like genetic heterogeneity and environmental variations, while genetic studies in animal models contain several advantages. With animal models, the environment can be controlled, the genetic complexity of the disease is minimized and the disease onset can be predicted, which simplify diagnosis and characterization. We use pristane-induced arthritis in rats to investigate the inheritance of arthritis. Until now, we have identified 15 loci that significantly predispose rats to the development of arthritis. One of these arthritis loci has been isolated and confirmed to be caused by a polymorphism in the Ncf1 gene. In this review, we outline the methods used to identify Ncf1 as one single susceptibility gene in a complex puzzle of inherited factors that render susceptibility to a complex autoimmune disorder like arthritis. [ABSTRACT FROM AUTHOR]

Abstract The nonobese diabetic mouse is highly susceptible not only to diabetes but to several autoimmune diseases, and one might suspect that these are controlled by a shared set of genes. However, based on various gene-segregation experiments, it seems that only a few loci are shared and that each disorder is influenced also by a unique set of genes. [ABSTRACT FROM AUTHOR]

Development of type-II collagen (CII)-induced arthritis (CIA) is dependent on a T-cell mediated activation of autoreactive B cells. However, it is still unclear if B cells can present CII to T cells. To investigate the role of B cells as antigen-presenting cells (APCs) for CII, we purified B cells from lymph nodes of immunized and nonimmunized mice. These B cells were used as APC for antigen-specific T-cell hybridomas. B cells from naYve mice did present native, triple-helical, CII (nCII) but also ovalbumin (OVA) and denatured CII (dCII) to antigen-specific T-cell hybridomas. In addition, B cells primed with nCII or OVA, but not dCII, activated the antigen-specific T-cell hybridomas two to three times better than naive B cells. We conclude that antigen-primed B cells have the capacity to process and present CII to primed T cells, and antigen-primed antigen-specific B cells are more efficient as APC than naYve B cells. We further conclude that B cells have the potential to play an important role as APC in the development of CIA. [ABSTRACT FROM AUTHOR]

The salivary gland inflammatory lesions and renal vasculitic lesions of autoimmune MRL/lpr mice were analyzed for the presence of activated lymphocytes Immunohistologic analysis revealed that the majority of lymphocyte-like cells in salivary glands and kindneys expressed CD4 antigen (> 50%). Lesser numbers of interleukin-2 receptor (IL-2R) expressing and interferon-gamma (IFN-γ)-producing cells were present (1-5%). CD4[SUP+], IL-2R[SUP+], and IFN-γ[SUP+] mononuclear cells were found in small inflammatory foci. In larger inflammatory foci the IFN-γ producing cells were detected in the periphery in comparable numbers as the IL-2R expressing cells although with different location. Large numbers of cells in the inflammatory foci also expressed MHC Class II molecules (> 50%). The expression of IL-2R and production of IFN-γ in the tissue lesions indicate presence of activated inflammatory T cells. Production of INF-γ by the infiltrating mononuclear cells may induce Class II antigens on epithelial cells and stimulate further T cell migration into the inflammatory site. [ABSTRACT FROM AUTHOR]

Interferon-γ (IFN-γ) mRNA expression of murine splenic CD8 + T cells in response to toxic shock syndrome toxin-1 (TSST-1) was examined in vitro. In primary response to TSST-1, purified CD8+ cells expressed a low frequency of IFN-γ mRNA and produced very little interleukin-2 (IL-2) compared with unseparated lymphocytes and purified CD4 + cells. The addition of IL-2 to the cell culture enhanced IFN-γ mRNA expression in the CD8+ population. Upon restimulation with TSST-1, no IL-2 production and hardly any IFN-γ mRNA expression were observed in the purified CD8+ lymphoblasts. Exogenously added IL-2 did not increase the IFN-γ mRNA expression in purified CD8+ blasts exposed to TSST-1. In contrast, stimulation with concanavalin A induced a high frequency of IFN-γ mRNA in purified CD8+ blasts. Moreover, TSST-1 induced strong IFN-γ mRNA expression in unseparated T lymphoblasts and purified CD4+ populations. Interestingly, a combined immunocytochemistry and in situ hybridization technique showed a high frequency of CD8+ IFN-γ mRNA-expressing cells in an unseparated blast population. These results demonstrate that TSST-1 induces a selective anergy within the purified CD8+ T-cell compartment and that the IFN-γ mRNA expression in CD8+ T blasts can be achieved by stimulation of unseparated T cells with TSST-1. [ABSTRACT FROM AUTHOR]

The aim of this study was to obtain further information about exocrine glandular immunopathology and the potential of the MRL/lpr strain as a model of Sjögren's syndrome. Immunoenzyme staining (ABC technique) and monoclonal antibodies defining CD3 T-cell receptor (TcR)αβ, γδ and TcR Vβ2, Vβ4, Vβ6, Vβ7, Vβ8.1,2, Vβ10b and Vβ11 were used to identify the mononuclear cells (MNC) in salivary gland infiltrates and lymph nodes of 2- and 4–5-month-old female MRL/lpr mice. TcRαβ+ cells dominated clearly over TcRγδ+ cells in both salivary glands and lymph nodes. In addition, to be expressed on lymphocyte-like cells. TcRγδ+ cells also had a dendritic appearance, The frequency pattern of TcR expression in early inflammation (2 months) was Vβ8.1,2 > Vβ6 > Vβ4 > Vβ10b > Vβ2 > Vβ7 > Vβ11. Clear differences in frequencies could be found between salivary glands and lymph nodes in established sialadenitis (4–5 months). Particularly Vβ4, Vβ8.1,2 and Vβ10b showed expansion in salivary glands at ≥4 months. In conclusion, this study shows a diverse repertoire of TcR at local sites of MNC infiltration in autoimmune MRL/lpr mice. However. with increasing age it also shows a preferential utilization of certain Vβ gene products. [ABSTRACT FROM AUTHOR]

Adjuvant arthritis in rats is usually induced by injection of mycobacterium tubercle cell wails suspended in various adjuvant oils such as Freund's incomplete adjuvant (HA) or pristane. We have recently shown that injection of adjuvant oils without inclusion of mycobacterium tubercle cell walls triggers arthritis [oil adjuvant induced arthritis (OIA)] in the DA rat strain. The OIA is a genetically restricted disease since only DA rats are susceptible while Lewis, DA-fostered Lewis and F1 (Lew × DA) rats are relatively resistant. Activated αβ T cells infiltrate the affected joints of adjuvant oil-injected DA rats and treatment with monoclonal antibodies to the αβ T-cell receptor abrogates development of arthritis. These findings show that αβ T-cell activation is a critical event in the development of OIA. [ABSTRACT FROM AUTHOR]

Oestrogen (E2) has been suggested to be responsible for the female preponderance for systemic lupus erythematosus (SLE) and for exacerbations of disease during pregnancy. In lupus-prone (NZB × NZW) F1 (NZB/W) mice, sex hormones also influence disease progression, thus long-term treatment of NZB/W mice with high doses oloestradiol increases the mortality in immune-complex mediated disease. We have previously demonstrated that E2 suppression of delayed-type hypersensitivity (DTH) to oxazolone (OXA) in NZB/W mice is inherited from the healthy NZW (H-2i) and not from the autoimmune NZB (H-2d) parental strain. In this paper we have analysed the influence of E2 on DTH and antibody responses to OXA in backcrosses of NZB/W mice and the NZB and NZW parental strains. Suppressed DTH was found in 15/16(94%) of female (NZB/W × NZW) F1 (NZB/ W/W) mice treated with E2. In contrast, only 32/63 (51%) of (NZB/W × NZB)F1 (NZB/W/B) mice treated with E2 displayed suppressed DTH reactivity. These two findings are compatible with a single, rather than multiple, dominant gene inherited from the NZW strain encoding for E2-mediated suppression of DTH in NZB/W mice. FACS analysis, using a monoclonal antibody recognizing the H.2z but not the H-2d locus, identified the H-2 expression (H-2dd and Hdz) of the NZB/W/B backerosses and revealed that E2 suppression of DTI-I is not linked to the H-2 haplotype of the backcrosses. Furthermore, E2 treatment of NZB/W/W mice, but not of NZB/W/B mice, significantly enhanced the serum levels of anti-OXA antibodies of both IgG and IgM classes. Based on our results it is tempting to speculate whether similar genetic factors for E2 sensitivity of the immune system may be of importance for the female predominance of human SLE. [ABSTRACT FROM AUTHOR]

Monoclonal anti-idiotypic antibodies previously shown to react with a cross-reactive idiotope of anti-collagen II auto-antibodies were used for in vivo treatment of DBA/1 mice receiving immunization with arthritogenic native rat collagen type II. Injection of 100 µg of the anti-idiotypic antibody 3 weeks before the collagen immunization resulted in a significant suppression of collagen arthritis, compared with mice treated with a monoclonal control antibody. The treatment with antiidiotypic antibody 3 weeks before collagen immunization could also cause a marked down-regulation of the total serum levels of anti-collagen il antibodies. When the anti-idiotypic antibodies were administered near the time for induction of arthritis (2 days after collagen immunization) a significant effect was seen on the collagen arthritis, but not on the levels of anti-collagen antibody. As collageninduced arthritis is a disease where both T- and B-cell mediated immunity are believed to play critical roles, the present effects of the in vivo anti-idiotype treatment on arthritis development could provide an interesting system for the study of idiotype regulation on both B- and T-cell arthritis-associated autoimmunity. [ABSTRACT FROM AUTHOR]

The influence of sex steroids on cutaneous delayed-type hypersensitivity (DTH) and antibody responses to oxazolone (OXA) in autoimmune and normal mouse strains has been investigated. The results show that: (i) treatment with 17/β-oestradiol (E2) suppresses DTH responses and stimulates antibody responses in MRL, B6 and C3H mice, suppresses DTH in DBA/1 mice, while having no effects on DTH or antibody responses in BALB/c and NFR/N mice. (ii) Treatment with testosterone suppresses the antibody response in all studied strains (MRL, B6, BALB/c and DBA/1) while down- regulating the DTH response only in MRL and B6 but not in BALB/c or DBA/I. (iii) Neither the lympho-proliferative (lpr) gene, which accelerates autoimmune disease, nor the H-2 genes seem to be directly related to the effects of sex hormones on the immune system. (iv) Susceptibility to oestrogen- and testosterone-mediated suppression of DTH but not oestrogen-mediated enhancement of antibody response are inherited as dominant traits. The results are discussed in the context of certain autoimmune diseases known to be influenced by sex hormone manipulations. [ABSTRACT FROM AUTHOR]

In this paper we report that treatment with 17β-oestradiol depresses cutaneous delayed-type hypersensitivity (DTH) to oxazolone (OXA) in female oophorectomized NZB/W mice. Analysis of the parental strains revealed that this oestrogen-induced inhibition of DTH mice is a trait inherited from the healthy NZW and not from the autoimmune NZB strain. The down-regulating effect of oestradiol on DTH in female NZB/W mice was found both in the sensitization and effector phase of the DTH response. Decreased DTH reactivity to OXA was demonstrated in oophorectomized NZB/W and NZW mice after administration of both low, physiological doses (s.c. injections) and high, pharmacological doses (siliac tube implantation) of oestradiol. In addition, s.c. implantation of testosterone containing siliac tubes suppressed DTH reactivity to OXA in castrated male NZW mice. This down-regulating effect was not found in male NZB or NZB/W mice similarly treated. Serological analysis revealed that high doses of oestradiol increased whereas testosterone depressed the IgG anti-OXA antibody responses in female NZB/W mice. Our results indicate that one possible contribution of the NZW parental strain to the lupus disease in NZB/W mice is a trait of oestrogen sensitivity leading to the acceleration of the autoimmune disease, the latter feature being inherited from NZB mice. [ABSTRACT FROM AUTHOR]

The MHC restriction of the antibody response and development of arthritis after immunization with autologous or heterologous type II collagens in mice have been investigated. Mice from three different H-2q-carrying strains (DBA/ 1, NFR/N and B10.G) with different non-MHC genes, as well as B10-congenic strains carrying wild type H -2q related or H-2r haplotypes, were susceptible for collagen arthritis. All strains tested developed an antibody response cross-reacting with autologous type II collagen after immunization with heterologous type II collagen; H-2q predisposes for a high response against chick, rat and bovine type II collagen, H-2r and H-2b for a high response against bovine type II collagen. Only mouse strains with H-2q, H-2r, H-2w3 or H-2w17 were responders to mouse type II collagen, and only these strains developed arthritis after immunization with heterologous or autologous type II collagens. These findings indicate that the ability to mount an immune response against autologous type II collagen is a prerequisite for the susceptibility to collagen arthritis. A cross-reactive autoimmune response after immunization with various heterologous type II collagen may enhance further the development of arthritis. [ABSTRACT FROM AUTHOR]

DBA/1 mice develop systemic polyarthritis and high titres of collagen autoantibodies after immunization with type II collagen. In this study we have analysed the frequency and specificity of antibody-producing B cells in draining lymph nodes 11 days after a primary immunization with rat type II collagen. A remarkably high frequency of type II collagen-reactive hybridomas (30%, n = 71), the majority cross-reacting with autologous type II collagen, were generated. Most of the collagen-reactive hybridomas produced IgG antibodies specific for type II collagen. Many other hybridomas produced multispecific antibodies (9%): these were preferentially of the IgM class. Some of the monoclonal multispecific hybridomas produced antibodies that cross-reacted with specific epitopes on the collagen molecule. One type II collagen-reactive hybridoma also displayed rheumatoid factor activity. Different mechanisms for the generation of the high frequency of collagen reactive antibodies are discussed. [ABSTRACT FROM AUTHOR]

Sialadenitis develops spontaneously in MRL/Mp mice bearing a lymphoproliferative gene, lpr (MRL/ Mp-lpr/lpr). Based on recent observations of an oligoclonal expansion of T-cell receptor (TCR) expressing Vβ chain families (Vβ4, Vβ8.1,2, Vβ10b) in salivary glands of these mice we have initiated selective antibody therapy. Treatment with monoclonal antibodies (MoAb) specific for T cells expressing a mixture of TCR Vβ4, Vβ8.1,2 and Vβ10b was applied to MRL/lpr mice before and after the spontaneous development of sialadenitis. The in vivo treatment with Vβ4, Vβ8.1,2 and Vβ10b MoAb did not prevent the development of sialadenitis. However, in animals with established sialadenitis, treatment with the MoAb significantly decreased the inflammation compared with the control groups. Immunohistochemical staining of cell phenotypes demonstrated a change in the ratio of CD4/CD8 in the animals with established sialadenitis. Altogether, these findings illustrate that it is possible to modulate sialadenitis and infiltrate cell phenotypes in vivo in MRL/lpr mice with specific anti-TCR Vβ MoAb treatment. [ABSTRACT FROM AUTHOR]

Hyaluronanreceptor (CD44) has been shown to be involved in lymphocyte homing during normal leucocyte circulation and during leucocyte extravasation into sites of tissue inflammation. In addition, interaction with CD44 molecule induces T-cell activation and production of cytokines, such as interferon-γ. In this study we have examined what influence interaction with the CD44 receptor would have on collagen II-induced arthritis in mice. Mice were immunized with rat collagen II and administered with injections of a monoclonal anti-CD44 antibody. Seventeen days after the outbreak of the disease, all of the anti-CD44 treated animals remained clinically healthy, whereas 37% of the controls displayed arthritis (P<0.001). Ten days later the prevalence of arthritis was 26% and 65% (P<0.05), respectively. Furthermore, the severity of the arthritis was significantly ameliorated by the anti-CD44 treatment. Serum levels of interferon-γ were significantly higher in collagen II immunized animals having been treated with anti-CD44, compared to the controls. Delayed-type hypersensitivity (DTH) response was significantly decreased in the anti-CD44 treated animals, indicating a functional suppression of T cells. In contrast, T cell independent experimental inflammation was not affected by the administration of CD44 antibodies. Our results suggest that interaction with CD44 down-regulates T lymphocyte/monocyte mediated inflammatory reaction, possibly by triggering of interferon-γ release. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Using a recently developed murine model of haematogenously induced Staphylococcus aureus, the authors have characterized the phenotypes and functional properties of inflammatory cells present in the synovium of arthritic mice. The results show that large numbers of granulocytes and macrophages were observed in the inflamed synovia within 24 h of inoculation of S. aureus strain LS-1. Many of the synovial macrophage-like cells stained for cytoplasmic IL-1α and TNF-α. Subsequently (≥ 48 h later), a prominent infiltration of T lymphocytes, predominantly of CD4+ phenotype, was observed. Some of the T lymphocytes stained for IL-2 receptor and intracytoplasmic interferon-γ (IFN-γ). Surprisingly, in spite of the severe inflammatory process, very few cells expressed MHC class-II molecules in the arthritic synovia. In addition, in vivo depletion of CD4+ T-cells resulted in a considerably milder course of staphylococcal arthritis. The similarities in the phenotype expression of synovial cells and central role of T-cells in S. aureus arthritis as well as in non-infectious models of arthritis, indicate that the process governing joint destruction is likely to be the same, irrespective of the initial stimulus. [ABSTRACT FROM AUTHOR]

Autoantibodies specific for type-II collagen (CII) occur in mice and rats with collagen-induced arthritis (CIA). The binding in vitro and in vivo of mouse monoclonal antibodies (MoAbs) specific for separate epitopes in CII have been investigated. Two-day-old mice were injected intraperitoneally (i.p.) with the anti-CII antibody CIID3 in both unlabelled and biotinylated form. It was found that antibodies binding to the same epitope in CII in vivo can inhibit others from binding in an epitope-specific fashion. The binding in vivo and in vitro of anti-CII antibodies could be inhibited also by an anti-idiotypic rat antiserum produced against the D3 antibody. The anti-idiotypic antiserum inhibited the binding of the antibody D3 and the idiotypically related antibody C2. The cDNA's of anti-CII antibodies D3, C2, and F4 were sequenced and found to contain germline encoded V-genes, apparently without somatic mutations. The variable heavy chain of D3 and C2 both expressed the same VH rearrangement, confirming that they share idiotypes. This report demonstrates that CII-specific germline-encoded IgG autoantibodies bind specifically to normal cartilage in vivo via their combining site. [ABSTRACT FROM AUTHOR]

Lewis rats develop arthritis after immunization with heterologous but not homologous rat type II collagen (CII). We have observed that if the rat CII is prepared by pepsin digestion without subsequent extensive purification, it is arthritogenic in Lewis rats. To address whether pepsin in the CII preparations contributed to the development of arthritis and whether this was associated with the induction of an immune response to CII, Lewis rats were immunized with rat CII of various degrees of purity and with various pepsin contents. After immunization with a crude preparation of CII, containing relatively large amounts of pepsin, Lewis rats developed arthritis with an incidence of 80% together with a strong anti-CII autoantibody production. Further purification of the CII on DEAE-Sepharose, which removes pepsin, eliminated the arthritogenic properties and the capacity to activate CII-specific B cells. Likewise, lathyritic CII, prepared without pepsin, induced neither a CII-specific immune response nor arthritis. If, however, pepsin was added to non-arthritogenic batches of rat CII, arthritis appeared at an incidence of 40%. By using an ELISPOT technique to detect antigen-specific interferon-γ-producing T cells and antibody-producing B cells, the immune response to CII and pepsin can be evaluated. Eleven days after immunization with lathyritic CII and pepsin, a B-cell response towards both CII and pepsin was seen. Pepsin-specific T cells were also seen at day 11, but CII-specific T cells did not appear until day 14 after immunization. In addition, a weak CII-specific proliferative response of the T cells could be demonstrated at day 14 but not at day 11 or 12. These data show that pepsin plays an important role in the triggering of a CII-specific immune response. We suggest a carrier-hapten mechanism where pepsin acts as a carrier and CII as a 'hapten' which will active CII-specific B cells. Subsequently these CII-specific B cells with break the T-cell tolerance and evoke a T-cell-mediated immune response towards CII. [ABSTRACT FROM AUTHOR]

The specificity of the recognition of type II collagen (CII) by T cells in the DBA/l mouse was analysed using fragments of chick and rat CII obtained by cyanogen bromide (CB) cleavage. Firstly DBA/l mice were immunized with chick CB fragments 5, K, 9, 10, 11 and 12. Ten days later the draining l>mph node cells were cultured with rat and mouse CM and the proliferative response was determined by incorporation of [³H]thymidine All peptides were capable of triggering T cells recognizing rat CII but only CB9 immunized mice responded well to mouse CII. Secondly, lymph node cells from DBA/l mice immunized with rat and mouse CII were cultured with the CB fragment, including rat CB10 and CB11, and the proliferative response was determined. After immunization with rat CII, the response was strongly dominated by T cells recognizing CBII with equal responses against chick and rat CB11, After immunization with mouse CII only rat CB10 gave a strong response It is concluded that several epitopes on the CH molecule can be recognized by T cells in the DBA/l mouse and that most of these epitopes are shared by rat and chick CII but not mouse CII. These epitopes exhibit strong immunodominance. In mice immunized with intact heterologous CII, the immuntidominant response is directed against one or more epitopes on the CB11 fragment present on several heterologous CII hut apparently not on mouse CII. In mice immunized with autologous CII the immunodominant response is directed against one or more epittipes on the CB10 fragment, present on rat and mouse CII. They are either absent in chick CII or located in the carboxyterminal end of the CB10 fragment where a cyanogen bromide cleavage site is present in chick CII but not in rat CII. These results suggest that the proposed importance of CBII in collagen-induced arthritis is due to activation of T cells reactive with heterologous CII only. These cells may be important for the induction of the strong auto-antibody-response after immunization with heterologous CII. Structures of importance for direct T-cell involvement in the arthritic process and recognized by autoreactive T cells are suggested to be found on CB10. [ABSTRACT FROM AUTHOR]

Arthritis was induced in DBA;1 mice by passive transfer of syngeneic anti-type 11 collagen (C11) serum concentrate. Alter transfer of serum containing 0.2 or 0.5 mg anti-Cll auto-antibodies the first clinical signs of arthritis appeared 48 h after injection. Severe clinical arthritis was detected with after injection. Immunohistochemical analyses of joints 48 h after serum injection revealed synovial foci in intercarpal and metacarpophalangeal joints of macrophage like cells, expressing C3bi-receptors and major histocompatibility complex class II molecules, and infiltration of Few CD4' lymphocytes. Later (96 h alter injection), the inflamed synovia were dominated by C3bi- receptor' potymorphonuclear cells. In contrast to conventionally induced collagen arthritis (CIA). the inflammatory infiltrates, tilling joint spaces and synovial tissue, were extensively dominated by polymorphonuclear cells, whereas macrophage-like.. cells expressing class 11 molecules and a few T-cells were seen only in the periphery of the developing pannus. The anti-CH serum induced arthritis may be used as a model for studies of humoral mediated mechanisms operating in conventionally induced CIA as well as in rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

An important question in local immune regulation in the skin is how keratinocytes at inflammatory sites can modify a local T-cell response to antigens introduced via the skin. In the present study we investigated the effects of rat epidermal cells obtained from the site of a tuberculin reaction, on the proliferative response of a syngeneic purified protein derivative (PPD)- specific CD4+ T-cell line. Epidermal cell suspensions from the tuberculin-reactive ears contained 23-37% cells expressing class II transplantation antigens as judged by immunocytochemistry compared with 2-3%, in normal epidermis. When comparing the capacity of these two different epidermal cell populations to induce a PPD-specific T-cell response in vitro, it was found that the PPD-reactive epidermal cells induced a lower T-cell response than did normal epidermal cells. This discrepancy cannot be explained by an infiltration of inflammatory cells unto the epidermis of tuberculin-reactive ears. Our data indicate that epidermal cells modified during a delayed-type hypersensitivity reaction in vivo may suppress an antigen-specific T-cell proliferation. [ABSTRACT FROM AUTHOR]

The role of CD8+ T 'cytotoxic/suppressor' T cells in induced immunospecific tolerance and during recovery after actively induced disease was examined by means of elimination of CD8+ cells from Lewis rats using in vivo treatment by Ox8 monoclonal antibodies, in experimental allergic neuritis (EAN). Animals depleted of CD8+ T cells after recovery from EAN did not show any clinical signs of relapse. Other animals were pretreated with the peripheral nerve basic protein P2 and thereby rendered resistant to disease induction with a potentially neuritogenic emulsion. The elimination of CD8+ T cells did not result in EAN here either. Thus, the CD8+ T-cell population does not seem to participate in the suppression of this autoimmune disease under these experimental conditions. [ABSTRACT FROM AUTHOR]

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/β-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 autoantibodies. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies reactive with different T lymphocyte antigens were administered to rats receiving heart allografts. Ox 19 antibodies (directed to the rat Ly 1 equivalent) and Ox 8 antibodies (directed to the rat CD8 equivalent) both prolonged graft survival, whereas W3/25 (anti-CD4). Ox 6 (anti-Ia), and W3/13 (anti-pan T) antibodies did not affect graft rejection. Immunohistological studies were carried out on spleen and graft specimens in order to analyse further the mechanisms behind the prolongation of graft survival. The observed almost complete absence of Ox 8-reactive cells in the spleen after treatment with Ox 8 antibodies corroborates earlier observations that injection of moderate amounts of Ox 8 antibodies leads to complete elimination of suppressor/cytotoxic T cells from peripheral lymphoid organs and blood. The present data on graft survival therefore both support the notion that suppressor/cytotoxic T cells are involved in graft rejection, and suggest that these cells are not the only ones involved. An unexpected and as yet unexplained finding was that Ox 8-reactive molecules were found in large numbers on various inflammatory cells as well as on certain myocytes in the grafted hearts that had experimented a prolonged graft survival due to treatment with Ox 8 or Ox 19 antibodies. [ABSTRACT FROM AUTHOR]

Binding of biotin-labelled native and denatured collagen type II and of aggregated IgG to frozen sections of synovial tissue from patients with rheumatoid arthritis (RA) or juvenile chronic arthritis (JCA) was investigated with the help of an avidin-biotin-peroxidase (ABC) technique. A large number of lymphocyte-like and plasma cell-like cells within the investigated biopsics aggregated IgG, and can be assumed to produce rheumatoid factors. In five out of six cases a smaller number of lymphocyte-like and plasma cell-like cells bound native collagen type II. Denatured collagen type II bound mainly to cells within the synovial lining and to endothelial cells within the inflamed synovial tissues. Binding of denatured but not of native collagen Ii was abolished by preincubation with rabbit antibodies towards human fibronectin. It is suggested that the method described here, using biotinylated antigens, may be of value for the study of local antibody production via investigations on frozen tissue sections, and that local antibody production against native collagen type II occurs within the inflamed synovial tissues at least in some cases of rheumatoid arthritis and juvenile arthritis. [ABSTRACT FROM AUTHOR]

Two monoclonal IgG rheumatoid factors were obtained after hybridization of spleen cells from DBA/1 mice immunized with immune complexes containing native collagen type II and a monoclonal anti-collagen II antibody. One of these rheumatoid factors reacted not only with purified murine Fe frangments, but also with Fab fragments of the anti-collagen II antibody used for immunization, whereas no reactivity was seen with Fab fragments from normal mouse IgG. The findings demonstrate the ability of immune complexes encompassing native collagen type II to induce production of IgG rheumatoid factors, and suggest that an idiotypic relationship may exist between certain rheumatoid factors and anti-collagen II antibodies. [ABSTRACT FROM AUTHOR]

Collagen type II-specific long-term cultured T helper cells, derived from the DBA/1 mouse, have been established and characterized. Clones from these T-cell lines could be shown to recognize either species-specific or species-nonspecific determinants on the collagen type II molecule, including determinants on autologous mouse collagen. Induction of arthritis via transfer to both irradiated and normal syngeneic recipient mice was obtained with both collagen type II-specific T-cell lines and an autoreactive and collagen type II-specific T-cell clone. Fewer cells were needed to evoke arthritis in normal than in irradiated recipients. Cells from lines and the clone used for transfer were by immunocytochemistry shown to have T helper phenotype. [ABSTRACT FROM AUTHOR]

The effects of intraperitoneal injection of monoclonal anti-rat T-lymphocyte antibodies were evaluated immunohistochemically and functionally in normal rats and in rats with experimental allergic neuritis. In the normal animals a single injection of OX8 antibodies, reactive with suppressor/cytotoxic T cells, completely eliminated OX8-reactive cells from peripheral lymphoid organs and from circulation, whereas the 'pan' T-cell-reactive W3/13 antibodies and the helper T-cell-reactive W3/25 antibodies only caused a partial elimination of their respective target cells. Injection of the W3/13 and W3/25 antibodies but not of OX8 antibodies led to a diminished responsiveness to allogeneic stimulation in vitro for spleen cells obtained from the treated rats, whereas the OX8 injection caused a complete elimination of the in vitro cytotoxic response to allogeneic cells in the mixed lymphocyte reaction-activated spleen cell population. When Lewis rats were injected with peripheral nerve myelin and Freund's adjuvant for the induction of EAN, treatment with W3/13 antibodies completely prevented the onset of disease, whereas treatment with the OX8 antibodies exaggerated the disease symptoms. [ABSTRACT FROM AUTHOR]

The involvement of different sets of lymphoid cells in the development of collagen II-induced arthritis in rats was studied by means of immunohistochemical analyses on frozen sections of tissue from joint biopsy specimens taken at different phases of arthritis development. Particular attention was paid to cells involved in early pannus formation. Accumulation of anti-Ia-reactive cells close to the cartilage surface was seen early in the development of pannus, and the anti-Ia reactive cells could in later phases be seen infiltrating cartilage and crowding bone surfaces at sites of marginal erosion. With the help of monoclonal anti-Ia-cell subset antibodies and rabbit anti-rat immunoglobulin antiserum, it was demonstrated that synovial infiltration of T lymphocytes, particularly W3/25-rcactive T ‘helper’ cells, occurs very early in the development of arthritis, whereas a moderate increase of Ox 8-positive ‘suppressor/cytotoxie’ T cells and a small number of B cells and plasma cells are seen later in the course of the disease. Levels of la-expressing cells and of T cells belonging lo different subsets were recorded in peripheral blood by means of immunocytochemical analyses on cell smears; no significant deviations from normal levels were seen during the development of arthritis. [ABSTRACT FROM AUTHOR]

Inflammatory infiltrates in sciatic nerves during the acute phase of experimental allergic neuritis in the Lewis rat have been characterized with regard to occurrence and distribution of Ia-expressing cells and T-lymphocyte subsets by the help of an immunohistochemical double-staining technique, enabling the simultaneous visualization of T lymphocytes and Ia-expressing non-T cells. Large numbers of Ia-expressing irregular macrophage-like/dendritic cells were seen both within inflammatory infiltrates and within afflicted nervous tissue. Many W3/13-reactive T lymphocytes of both 'helper' and 'suppressor/cytoxic' phenotypes appeared in close contact with these Ia-expressing non-T cells, particularly within the infiltrates. B lymphocytes and plasma cells were relatively few and mainly found close to endoneurial vessels. [ABSTRACT FROM AUTHOR]

The importance of T-cell receptor (TcR)Vβ gene haplotype and complement component CS deficiency for the resistance to collagen-induced arthritis (CIA) in the SWR mouse was studied. Firstly, the immune responses against heterologous and autologous type II collagen (CII) were compared between SWR mice and arthritis-susceptible and major histocompatibility complex (MHC)-identical DBA/l mice. Secondly, F1 and F2 crosses were made between the two strains and studied for arthritis development, Vβ gene usage and CS presence. After immunization with heterologous rat CII, both strains reacted with a strong autoantibody response. Immunization with mouse CII, on the other hand, gave a much lower response in both strains, with DBA/l mice having the strongest response. A collection of B-cell hybridomas was created from the draining lymph nodes of SWR mice 9 days after immunization with rat CII. This hybridoma collection showed similarity to previous data from the DBA/1 mouse, by its high frequency of B cells producing IgG specific for CII and with a high degree of cross-reactivity with autologous mouse CII. After immunization with heterologous CII, both T cells specific for heterologous CII as well as T cells cross-reacting with autologous CII could be demonstrated. F1 crosses between SWR and DBA/l were relatively resistant to CIA (8%), while in the F2 generation 72% of the mice developed arthritis. No correlation between Vβ haplotype or CS and development of arthritis in the F2 mice was found. It is concluded that the resistance to CIA in the SWR mouse is not related to either Vβ haplotype or C5 deficiency. Instead we postulate the involvement of two or more genes which are important for the induction and maintenance of tolerance to own CII. [ABSTRACT FROM AUTHOR]

The present study addresses the question of whether there is a difference in the frequencies of autoantibody-producing B-cell precursors in healthy compared with lupus-prone mouse strains. Spleen mononuclear cells (MNC) from 4-week-old (i.e. at the preclinical stage of lupus) mice were activated in vitro for 3 and 6 days with lipopolysaccharides (LPS) and the numbers of IgG, IgA and IgM autoantibody-producing cells were analysed by the ELISPOT assay. The results indicate a high frequency of IgM autoantibody-secreting cells after both 3 and 6 days in vitro stimulation. In spite of high frequencies of IgG-producing cells appearing late during the course of LPS stimulation, no IgG or IgA autoantibody producing cells were detected. No significant differences in the autoantibody repertoire were noted between healthy and lupus-prone mice, indicating that independent of the genetic background the immune system has the capacity to react with autoantibody production. Phenotypic analysis of LPS-induced, IgM-secreting B cells showed clearly that the majority of them were surface IgM+, CD5+ but Thy-1-. [ABSTRACT FROM AUTHOR]

The M RL-1pr/1pr (MRL/1) mouse spontaneously develops an autoimmune disease associated with various rheumatic manifestations. We have studied the histological features of sialadenitis and utilized an immunohistochemical staining technique on frozen tissue sections to analyse the cellular composition of the salivary glands at varying stages of disease. Semiquantitative assessment of the infiltration disclosed a focal inflammation which started at 2 months of age and was progressive until 5 months of age in submandibular glands. A high frequency of Ly-1 and L3T4-positive cells was observed at all stages of sialadenitis, whereas Lyt-2 positive cells were found at a lower frequency. Ia expression was seen on a large proportion of the infiltrating cells and also on ductal and glandular epithelial cells in the vicinity of the inflammatory lesions. The presence of la antigens on many inflammatory as well as resident cells and the high frequency of lymphocytes with 'helper' phenotype may indicate a perpetuated immunological activation within salivary glands. [ABSTRACT FROM AUTHOR]

In normal murine epidermis Thy-1 antigen is known to be strongly expressed on a dendritic population of bone marrow derived cells lacking Ia antigens and faintly on keratinocytes. We now report on the induction of pronounced expression of Thy-1 antigen on keratinocytes by immunological stimuli as well as by chemical irritation and wounding. In contrast the induction of Ia antigens on keratinocytes is more restricted. It has been suggested that the dendritic Thy-1+ cells can suppress an immune response initiated by Ia antigen expressing Langerhans cells. The balance within epidermis between up- and down-regulation of immune reactions, may be even more complex if also keratinocytes expressing Thy- 1 and/or Ia antigens should prove to participate. [ABSTRACT FROM AUTHOR]

Collagen type II (CII) induced arthritis (CIA) in mice is an experimental model for rheumatoid arthritis. Induction with non-self (e.g. human) CII induces severe arthritis whereas the mice are less susceptible to induction with self CII (i.e. mouse). To analyse whether an autoimmune response to human CII can develop and is pathogenic the authors have established transgenic mice expressing human CII in cartilage and backcrossed them into two different gene backgrounds susceptible to CIA (DBA/1 and C3H.Q). The transgenic human CII expression was restricted to cartilage and did not disturb cartilage morphology or lead to chondrodystrophy. In addition, development of stress-induced arthritis was not affected by the transgene. The cartilage specific expression of human CII reduced, but did not eliminate, the susceptibility to CIA irrespective of the species source (human, bovine, chick, rat) of CII used for immunization. A common denominator between these heterologous CII in comparison with mouse CII is the previously defined CII 256-270 epitope. An expression level dependent T-cell tolerance was seen in this epitope as well as to the entire CII. However, all human transgenic mouse lines could still mount significant autoreactive T- and B-cell responses. Approximately 10% of the transgenic mice developed arthritis after immunization with human CII. These findings show, therefore, that cartilage-located human CII induce tolerance but can nevertheless be a target for development of arthritis. [ABSTRACT FROM AUTHOR]

The importance of the MHC class II region for the development of septic arthritis was studied in a murine model of haematogenously induced Staphylococcus aureus arthritis. In the first experiment MHC class II deficient mice (Aβ-/-) and their heterozygous (Aβ+/-) littemates were intravenously inoculated with a single dose of toxic shock syndrome toxin-1 producing S. aureus LS-1 strain. The results demonstrate that the expression of class II MHC molecules increases the prevalence and severity of arthritis. To analyse the impact of MHC class II haplotypes on the disease onset and progression the authors used congenic C3H.NB, C3H.Q and C3H/HeJ mice in the second set of experiments. The results show that C3H/HeJ mice developed the highest frequency and the most severe course of arthritis compared with C3H.NB and C3H.Q animals. Immunohistochemical analysis of arthritic joints revealed equal number of macrophages, CD4+ and CD8+ lymphocytes in the inflamed synovia in all the congenic mice. In contrast, the number of MHC class II expressing cells was higher in the arthritic joints of C3H/HeJ mice compared with the congenic strains (P< 0.001). Furthermore, serum levels of proarthrtitogenic cytokines. such as tumour necrosis factor and interleukin-6 were higher in C3H/HeJ group. This study indicates that MHC class II expression is necessary for the development of S. aureus arthritis in mice and that different MHC class II haplotypes confer varying susceptibility for development of joint inflammation induced by staphylococci. [ABSTRACT FROM AUTHOR]

The collagen-induced arthritis model in DA rats induced with homologous rat type II collagen was chosen to determine the therapeutic capacity and effects on autoimmunity by IL-10. Systemic IL-10 treatment (100 or 10 µg/day) with mini-osmotic pumps during the periods of arthritis onset (days 12-20 after immunization) decreased the frequency of arthritis and delayed the onset and reduced the severity of arthritis in the few rats that eventually developed arthritis. Concomitantly, levels of autoantibodies to CII were reduced. To test the activity on established arthritis, IL-10 was administered subcutaneously in the paws. This treatment reduced the swelling but did not block the arthritis process. The effective treatment required 100µg of IL-10 every 12th hour while 50 µg of IL-10 had little effect, although a tendency of reduced paw swelling was observed. Surprisingly, therapeutic IL-10 treatment led to higher serum levels of autoantibodies to CII. The highest doses of IL-10 (100 µg) did not show any apparent toxic effects when given locally or systematically. Taken together, this study suggests that IL-10 is a candidate for treatment of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]