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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]

Protein energy malnutrition decreased the number of rosette forming T lymphocytes, of T4 positive cells and their ability to provide help to B cells in antibody synthesis. There was a reduction in serum thymic hormone activity and an elevation of leucocyte terminal transferase and plasma cortisol levels. The numerical and functional deficiency of T4+ helper cells may be important in the pathogenesis of some of the clinical and immunological manifestations of protein energy malnutrition. [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]

Susceptibility lo collagen-induced arthritis (CIA) in mice is associated with a class II gene in MHC (A9) but also with unknown genes outside MHC. Investigated here is the influence of genes on the X chromosome as well as the role of the X-linked immunodeficiency (xid) mutation. Reciprocal male F1 hybrids, bred to be heterozygous or homozygous for A9, showed a genetic influence in their susceptibility to develop CIA. Crosses were made between B 10, G, B10, Q, DBA/I, SWR/J, C3H, Q and CBA/Ca, and all F1 mice were castrated to avoid sex hormone modulation of the susceptibility. A differential timing of arthritis onset and severity were seen in the reciprocal F1 males. An exception was the reciprocal F1 male offspring from SWR/J and DBA/1 crosses which differed only in disease severity late in the course of the disease. The female F1 crosses did not show the same pattern of differential susceptibility to CIA as the F1 males. To exclude the possible influence of the Y chromosome, F1 males of reciprocal crosses were hack-crossed lo the parental strains creating offspring with equal X chromosomes but divergent Y chromosomes. No difference in development of arthritis was observed in these. The influence of the xid mutation was investigated next. The xid loci from the CBA/N mouse was bred into DBA/1 strain which is highly susceptible to CIA, The resulting congenic DBA/l-xid strain was resistant to induction of CIA and did not develop an antibody response to type II collagen. We conclude that polymorphic genes on the X chromosome modulate susceptibility to CIA. The results from the experiments with mice carrying xid mutations confirm that such immune modulating genes exist on the sex chromosomes. [ABSTRACT FROM AUTHOR]

To extend our previous findings that exposure to constant darkness (stimulation of endogenous melatonin release) as well as treatment with exogenous melatonin magnifies the severity of collagen-induced arthritis in mice, we have examined the effects of melatonin cutback by removing the pineal gland. Two strains of mice, DBA/1 and NFR/N, were subjected to surgical pinealectomy. The melatonin levels in sera were reduced by approximately 70% by the pinealeetomy compared with the corresponding sham-operated controls. After 3-4 weeks of rest the mice were immunized with rat type II collagen to induce autoimmune arthritis, and the animals were kept in constant darkness during the experiments. In comparison with the controls, all groups of pinealectomized mice showed reduced severity of the arthritis by means of (i) a slower onset of the disease, (ii) a less severe course of the disease (reduced clinical scores), and (iii) reduced serum levels of anti-collagen II antibodies. These effects were not significant in all experiments, but the trends were always the same. Thus, the present results strengthen the hypothesis that high physiological levels of melatonin (which can be induced by exposure to darkness) stimulate the immune system and cause exacerbation of autoimmune collagen II arthritis, while inhibition of melatonin release (pinealectomy or exposure to light) has a beneficial effect. [ABSTRACT FROM AUTHOR]

The F1 hybrid mouse strain, from B10Q and DBA/1 parentals (the QD strain), is highly susceptible to induction of type II collagen-induced arthritis, an experimental model for rheumatoid arthritis. Males are more susceptible than females. Oophorectomy enhances susceptibility to arthritis and treatment with physiological doses of 17β-oestradiol (E2) suppresses disease. E2 treatment lowers the incidence of arthritis also in non-castrated and castrated males, showing that the anti-arthritic effect by oestrogen is not dependent on either sex hormone imprinting effects or interference with male sex hormones. Testosterone treatment of normal females, but not of castrated females, exaggerated development of the disease. In the testosterone-treated normal females, the oestrogen effect on vaginal smear was abolished and ovarian weight decreased, suggesting that the testosterone-mediated enhancing effect is caused by inhibition of ovarian oestrogen production. The crucial importance of oestrogens for the development of arthritis is focused on the effectiveness of treatment with gestation-related doses of E2 of normal, non-castrated females. [ABSTRACT FROM AUTHOR]

DBA/1 male mice develop arthritis spontaneously al the age of 4 months. The affected joints show cell-rich pannus formation without T cell infiltration and only limited MHC class II expression. Specific pathogen-tree DBA/1 mice from different sources developed the same disease. Analyses of inbred mouse strains with various genetic backgrounds and Fl hybrids revealed that the disease is genetically dependent of DBA/I recessive genes. However. Fl hybrids between DBA/1 and BXSB spontaneously developed arthritis with earlier onset than DBA/I mice, suggesting that the BXSB autoimmune gene background had both permissive and contributing effects on the development of arthritis. The complete male preponderance for disease susceptibility was investigated by castration and testosterone treatment of DBA/1 males. No arthritis developed after castration and disease susceptibility was restored by testosterone treatment. Arthritis developed only where more than two males were kept in cages, suggesting an influence by aggressive behaviour. Thus, the spontaneous development of arthritis is dependent on hormonal and behavioural mediated effects and differs from experimental models for rheumatoid arthritis such as type II collagen-induced arthritis and pristine induced arthritis. We conclude that the spontaneously developing arthritis in the normal DBA/I strain may be more useful as a disease model for osteoarthritis than for rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

The DA rat is highly susceptible to induction of arthritis after immunization with homologous type 11 collagen (CIA) emulsified in Freund's incomplete adjuvant (FIA), resulting in collagen-induced arthritis (CIA). The DA rat also develops arthritis after injection of FIA alone (oil-induced arthritis (OIA)). This finding allows a direct comparison of two different models for rheumatoid arthritis; one induced with a defined auto-immunogen and one with a pure adjuvant. Both CIA and OIA develop approximately 2 weeks after induction but OIA is a self-limited acute disease whereas CIA induced with homologous CII follows a chronic disease course. Immunization with CII leads to a strong autoantibody response to CM while injection of FIA leads to no or very limited anti-CII antibody response. The Lewis rat develops neither CIA nor OIA while F1(DA × Lewis) rats develop CIA but not OIA-Olive oil or CII emulsified in olive oil docs not induce arthritis in DA rats. Pretreatment with CII in olive oil vaccinates against CIA but not OIA whereas pretreatment with FIA vaccinates against OIA but not CIA. These findings demonstrate that inclusion of CII in the adjuvant leads to a disease distinct from OIA which is characterized by a CII autoimmune response and chronicity of the disease course. [ABSTRACT FROM AUTHOR]

Experimental animal models can be used to help understand how oestrogen modulates autoimmune arthritis. We have previously shown that castration of female DBA/1 mice exaggerates arthritis induced with type II collagen. This report shows that treatment of castrated DBA/1 mice with low doses (0.2 μg twice a week) of β-oestradiol reduces the incidence (37%, vs78% in controls) and severity (3.9 vs 5.6 mean scores) of arthritis. Levels of IgG anti type II collagen antibodies are decreased whereas levels of IgM antibodies are increased in the β-oestradiol treated mice. The T cell response, as measured by a ³H-thymidine assay,, is reduced in the β-oestradiol treated mice. The results suggest that treatment with low doses of β-oestradiol exerts a suppressive effect on both development of collagen arthritis as well as T cell dependent immune reactivity towards type II collagen. [ABSTRACT FROM AUTHOR]

The kinetics and mechanisms for secretion of antibodies against native and denatured collagen type II have been studied in spontaneously arthritic MRL/l mice. Circulating antibodies were quantified by an ELISA assay and frequencies of specific antibody secreting spleen cells by an ELISPOT assay. The degree of humoral immunity to collagen type II increased at late stages of the disease (6 months of age) whereas severe synovitis was seen earlier (5 months of age). Both the appearance of anti-collagen II producing cells and development of synovitis was preceded by and not correlated with a general state of polyclonal B cell activation. In MRL/l mice, collagen II specific antibodies appeared spontaneously and titres were largely unaffected by collagen II immunization. The levels of circulating anti-collagen II antibodies in MRL/l mice were lower, and the antibodies displayed lower avidities and different specificities as compared with the antibodies generated in collagen II high responder DBA/l mice after immunization with collagen II. It is suggested that the antibody response in MRL/l mice against collagen type II docs not need MHC-restricted T cell help and that induction of antibody production to collagen II in MRL/l mice is triggered by joint cartilage destruction and subsequent collagen II release. [ABSTRACT FROM AUTHOR]

Native type II collagens of rat, chick, bovine, human and murine origin have been used for immunization of male and female DBA/1 mice of different ages. The four heterologous collagens were able to induce arthritis in both male and female mice although the incidence of arthritis was higher in males. The onset of arthritis was sudden with severe lesions starting to appear 5- to 6-weeks after immunization. Mouse collagen II, on the other hand, caused arthritis exclusively in males. The onset of arthritis was in the latter case less dramatic and usually delayed until 12- to 14-weeks post immunization. Antibody production against both the immunogen and other type II collagens, including mouse collagen was seen in both arthritic and non-arthritic animals, and antibody titres against both the collagen used for immunization and mouse collagen were higher in the sera from arthritic than in identically immunized non-arthritic animals. Total amounts of auto-anti- collagen II antibodies were, however, more dependent on which collagen preparation was used for immunization than on whether the immunized mice developed arthritis or not. These results indicate that arthritis induction in mice is not dependent solely on the levels of auto reactive anti-collagen II antibodies. [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]

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]

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]

SUMMARY The high number of γ /δ -expressing T cells found in the epithelial lining layer suggests that they form a first line of defence against invading pathogens. To evaluate the role of γ /δ T cell-receptor (TCR)-expressing cells in cutaneous infection caused by Staphylococcus aureus , mice lacking γ /δ -expressing T cells (TCRδ-/- ) were inoculated intradermally with S. aureus, and compared with S. aureus -infected congeneic TCRδ+/- control mice. The number of bacteria recovered from the skin of TCRδ-/- mice was significantly higher (P = 0·0071) at early time-points after inoculation compared to the number of bacteria isolated from infected TCRδ+/ - congeneic controls. Nevertheless, inflammatory responses measured as serum IL-6 levels, were significantly lower in TCRδ-/- mice than in the control group. A possible explanation for this discrepancy was the observation of significantly decreased overall numbers of infiltrating cutaneous T lymphocytes, which are important producers of IL-6. These results support the notion that the γ /δ -expressing T cells that reside at the epithelial lining layer of the skin is of importance for early containment of the bacteria, thereby limiting their replication and spread. [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]

SUMMARY Rheumatoid arthritis (RA) is a chronic inflammatory disease primarily affecting cartilaginous joints but also extra-articular tissues such as the nose and upper respiratory tract. We have investigated extra-articular cartilage involvement in two commonly used animal models for RA, collagen-induced and pristane-induced arthritis, by immunizing rats with different susceptibility to disease (LEW.1 A, LEW.1F and DA rats). We found that nasal and tracheolaryngeal cartilage is affected in LEW.1 A and DA rats to varying degrees in collagen-induced arthritis but not in any strain in the pristane-induced model. Antibodies to matrilin-1, a cartilage-specific protein expressed mainly in tracheolaryngeal and nasal cartilage but not in joints, were positively associated with the presence of inflammation in nasal cartilage. In contrast, no antibody response to matrilin-1 could be detected in pristane-induced arthritis. In addition, nasal vaccination with collagen type II prior to immunization in DA rats significantly decreased the antibody response to matrilin-1 at day 56, but not at earlier time points, indicating a late protective effect on extra-articular cartilage. We conclude that pristane-induced arthritis is a joint-specific model whereas collagen-induced arthritis affect joints as well as extra-articular cartilage. Furthermore, collagen immunization induces an antibody response to matrilin-1. [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]

Pregnancy is known to influence the course of rheumatoid arthritis (RA) in women, as well as type II collagen-Induced arihritis (CIA) in DBA/I mice. A characteristic feature is the remission during gestation and the exacerbation of the diseases during the post-partum period. In the case of CIA in DBA/1 mice, two hormonal changes have been assumed to be critical for the induction of the postpartum flare: (i) the fall in steroid hormone levels from those present during pregnancy; and (ii) surges of prolactin (PRL) release at and after delivery. Our results show that treatment with oestradiol during a short period immediately after parturition protects the mouse from a post-partum flare of the disease, and that treatment with broniocriptine, a drug known to inhibit the endogenous PRL release, has a significant though less marked effect. Studies of lactating (i.e. animals with physiological stimulation of endogenous PRL release) and non-lactating arthritic mice revealed no clear-cut differences. Indicating that PRL is of minor importance for the induction of the post-partum flare. Some steroids other than oestradiol, which may be implicated in the exacerbation of arthritis, namely progesterone and hydrocortisone. had no clinical effect. Analyses of agalactosyl IgG levels in mice with CIA, and anti-collagen II antibodies in sera collected at the end of the experiments revealed no significant differences between the oestradiol and the control groups. The successful oestradiol treatment of the mice indicates that the drop in endogenous oestradiol levels prior to delivery ends the oestrogen-mediated protection against arthritis during pregnancy. [ABSTRACT FROM AUTHOR]

The influence of oestrogen on the lupus disease in MRL/I mice has been investigated. Adult, castrated male and female MRL/I mice were administered with s.c. injections of 3.2 μg of 17&bea;-oestradiol twice a week. The results clearly demonstrate that a relatively small dose of oestrogen is a potent accelerator of the lupus disease in this mouse strain. Thus, administration of oestrogen accelerates glomerulonephritis. lymphoproliferation and mortality. Our results also indicate that oestrogen exerts a dual effect on the immune system of MRL/l mice by depression of antigen-specific and mitogen-induced I cell responses as well as enhancement of polyclonal B cell activation and autoantibody formation. In addition, even short-term administration of oestrogen in the preclinical phase oft he disease resulted in long-lasting effects as evaluated by reduced longevity and aggravation of renal disease. [ABSTRACT FROM AUTHOR]

During the delayed type of hypersensitivity (DTH) reaction in the skin, class II transplantation antigens are expressed on the keratinocytes. This induction is attributed to the action of y-interferon (IFN-γ). We have now studied the influence of antibodies against IFN-γ on the DTH-reaction. Lewis rats were sensitized to 2,4-dinitro-1-fluorobenzene (DNFB) and challenged 5 days later with DNFB on the ears. Immediately before challenge each animal in one group (n = 16) was given I mg of mouse monoclonal antibodies (MoAb) against rats IFN-γ, denoted DB-l, intraperitoneally (i.p.). another group (n = 15), 1 mg of an irrelevant MoAb and a third group (n = 11) was left untreated. The ear thickness was measured with a micrometer, before challenge and after 24, 48 and 72 h. At 72 h all rats were killed, the ears cut off, snap frozen and stained with immunoperoxidase using MoAbs OX 6 and OX 17, directed against rat class II antigens. The DB-1 treated group was found to have a larger ear swelling that was statistically significant at each time point compared with the other two groups. Furthermore, the animals given DB-1 showed class II antigen expression on Langerhans' cells, but almost none on keratinocytes. In contrast, the rats in the two other groups displayed a moderate to strong expression of class H antigens on keratinocytes as well as on Langerhans' cells. It is concluded that DB-l can inhibit class II antigen expression on keratinocytes during the DTH- reaction and also enhance the local response. [ABSTRACT FROM AUTHOR]

Summary: Psoriasis (Ps), psoriatic arthritis (PsA) and rheumatoid arthritis (RA) are common diseases dependent on environmental factors that activate the immune system in unknown ways. Mannan is a group of polysaccharides common in the environment; they are potentially pathogenic, because at least some of them induce Ps‐, PsA‐ and RA‐like inflammation in mice. Here, we used positron emission tomography/computed tomography to examine in‐vivo transport and spread of mannan labelled with fluorine‐18 [18F]. The results showed that mannan was transported to joints (knee) and bone marrow (tibia) of mice within 6 h after intraperitoneal injection. The time it took to transport mannan, and its presence in blood, indicated cellular transport of mannan within the circulatory system. In addition, mannan was filtered mainly through the spleen and liver. [18F]fluoromannan was excreted via kidneys, small intestine and, to some extent, the mouth. In conclusion, mannan reaches joints rapidly after injection, which may explain why mannan‐induced inflammatory disease is targeted to these tissues. [ABSTRACT FROM AUTHOR]

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]

Oestradiol and the selective oestrogen receptor modulator (SERM) raloxifene have been shown to ameliorate collagen-induced arthritis (CIA) in rats and in mice. One aim was to investigate if raloxifene exerts its anti-arthritic and anti-osteoporotic effects during the induction or effector phase of arthritis. A second aim was to analyse if raloxifene activates the oestrogen response element (ERE) to produce its immune-modulator effects. CIA or collagen-antibody-induced arthritis (CAIA) was induced in ovariectomized DBA/1-mice. CIA was used for evaluation of treatment during the induction, and CAIA for the effector phase of arthritis and osteoporosis development. Raloxifene, oestradiol or vehicle was administered 5 days/week. The clinical disease was evaluated continuously. Bone marrow density (BMD) was analysed with peripheral quantitative computer tomography, paws were collected for histological examination, and sera were analysed for markers of bone and cartilage turnover and proinflammatory cytokines. Transgenic luciferase (Luc)-ERE mice were immunized with collagen (CII), and after 10 days injected once with raloxifene, oestradiol or vehicle before termination. Spleens were analysed for luciferase activity to measure ERE activation. Treatment with oestradiol or raloxifene during the induction phase of CIA failed to affect arthritis. Raloxifene did not hamper disease activity in CAIA, whereas oestradiol delayed the onset and ameliorated the severity. Both raloxifene and oestradiol preserved BMD in CAIA. CII-immunization increased the oestradiol-induced ERE activation in spleen, and raloxifene activated the ERE at about 25% the intensity of oestradiol. Further experiments are needed to elucidate the exact mechanisms behind this finding. [ABSTRACT FROM AUTHOR]

In this study, we sought to determine the effect of the quantitative trait locus Pia7 on arthritis severity. The regulatory locus derived from the arthritis-resistant E3 rat strain was introgressed into the arthritis-susceptibility DA strain through continuous backcrossing. Congenic rats were studied for their susceptibility to experimental arthritis using pristane and adjuvant oil. In addition, cell number and function of various leukocyte populations were analyzed either under naive or stimulated conditions. We found that the minimal congenic fragment of DA.E3-Pia7 rats overlapped with the minimal fragment in DA.PVG-Oia2 congenic rats, which has been positionally cloned to the antigen-presenting lectin-like receptor complex (APLEC) genes. DA.E3-Pia7 congenic rats were protected from both PIA and OIA, but the protection was more pronounced in OIA. In adoptive transfer experiments we observed that the Pia7 locus controlled the priming of arthritogenic T cells and not the effector phase. In addition, Pia7 congenic rats had a significant higher frequency of B cells and granulocytes as well as TNFα production after stimulation, indicating a higher activation state of cells of the innate immune system. In conclusion, this study shows that the APLEC locus is a major locus regulating the severity of experimentally induced arthritis in rats. [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]

The expression of genes specifically in B cells is of great interest in both experimental immunology as well as in future clinical gene therapy. We have constructed a novel enhanced B cell-specific promoter (Igk-E) consisting of an immunoglobulin kappa (Igk) minimal promoter combined with an intronic enhancer sequence and a 3′ enhancer sequence from Ig genes. The Igk-E promoter was cloned into a lentiviral vector and used to control expression of enhanced green fluorescent protein (eGFP). Transduction of murine B-cell lymphoma cell lines and activated primary splenic B cells, with IgK-E-eGFP lentivirus, resulted in expression of eGFP, as analysed by flow cytometry, whereas expression in non-B cells was absent. The specificity of the promoter was further examined by transducing Lin− bone marrow with Igk-E-eGFP lentivirus and reconstituting lethally irradiated mice. After 16 weeks flow cytometry of lymphoid tissues revealed eGFP expression by CD19+ cells, but not by CD3+, CD11b+, CD11c+ or Gr-1+ cells. CD19+ cells were comprised of both marginal zone B cells and recirculating follicular B cells. Activated human peripheral mononuclear cells were also transduced with Igk-E-eGFP lentivirus under conditions of selective B-cell activation. The Igk-E promoter was able to drive expression of eGFP only in CD19+ cells, while eGFP was expressed by both spleen focus-forming virus and cytomegalovirus constitutive promoters in CD19+ and CD3+ lymphocytes. These data demonstrate that in these conditions the Igk-E promoter is cell specific and controls efficient expression of a reporter protein in mouse and human B cells in the context of a lentiviral vector.Gene Therapy (2007) 14, 1623–1631; doi:10.1038/sj.gt.3303021; published online 13 September 2007 [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]

One of the major quantitative trait loci (QTLs) associated with arthritis in crosses between B10.RIII and RIIIS/J mice is the Cia5 on chromosome 3. Early in the congenic mapping process it was clear that the locus was complex, consisting of several subloci with small effects. Therefore, we developed two novel strategies to dissect a QTL: the partial advanced intercross (PAI) strategy, with which we recently found the Cia5 region to consist of three loci, Cia5, Cia21 and Cia22, and now we introduce the QTL-chip strategy, where we have combined congenic mapping with a QTL-restricted expression profiling using a novel microarray design. The expression of QTL genes was compared between parental and congenic mice in lymph node, spleen and paw samples in five biological replicates and in dye-swapped experiments at three time points during the induction phase of arthritis. The QTL chip approach revealed 4 genes located in Cia21, differently expressed in lymph nodes, and 14 genes in Cia22, located within two clusters. One cluster contains six genes, differently expressed in spleen, and the second cluster contains eight genes, differently expressed in paws. We conclude the QTL-chip strategy to be valuable in the selection of candidate genes to be prioritized for further investigation.Genes and Immunity (2005) 6, 575–583. doi:10.1038/sj.gene.6364242; published online 14 July 2005 [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]

Identification of genes controlling complex diseases has proven to be difficult; however, animal models may pave the way to determine how low penetrant genes interact to promote disease development. We have dissected the Cia5/Eae3 susceptibility locus on mouse chromosome 3 previously identified to control disease in experimental models of multiple sclerosis and rheumatoid arthritis. Congenic strains showed significant but small effects on severity of both diseases. To improve the penetrance, we have now used a new strategy that defines the genetic interactions. The QTL interacted with another locus on chromosome 15 and a partial advanced intercross breeding of the two congenic strains for eight generations accumulated enough statistical power to identify interactions with several loci on chromosome 15. Thereby, three separate loci within the original QTL could be identified; Cia5 affected the onset of arthritis by an additive interaction with Cia31 on chromosome 15, whereas the Cia21 and Cia22 affected severity during the chronic phase of the disease through an epistatic interaction with Cia32 on chromosome 15. The definition of genetic interactions was a prerequisite to dissect the Cia5 QTL and we suggest the partial advanced intercross strategy to be helpful also for dissecting other QTL controlling complex phenotypes.Genes and Immunity (2005) 6, 175-185. doi:10.1038/sj.gene.6364155 Published online 17 February 2005 [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]

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]

The purpose of the study was to map the dominant T ceil epitope of the CBIl sequence of CII in RTIu huplotype rats and lo determine if, when used as a synthetic peptide, it would induce tolerance to protect against CIA. A dominant epitope corresponding to residues 184-198 included in the sequence of the CBII fragment of bovine CII was identified in proliferation assay using peptides in an epitope scanning system using synthetic peptides of 15 amino acids, overlapping by 12 amino acids. This epitope is bovine-specific, but cross-reacts with the corresponding rat peptide. Minor epitopes in the bovine CBII sequence were also autoantigenic. Use of independently synthesized and purified 184-198 peptide confirmed its dominance in the T cell responses of arthritic rats. The peptide itself was not arthritogenic. Cells from lymph nodes draining arthritic feel were particularly responsive to the dominant peptide sequence, and showed evidence of epitope spreading to include reactions to at least four subdominant epitopes. Mucosal tolerance was successfully induced by instilling CII into the nose of rats before induction of CIA; this was found to delay the onset of disease, reduce mean disease severity, shift the anti-CII antibody response to favour antibodies of the IgGl, rather than the lgG2b isiotype, and to reduce T cell reactivity to both CII and to the 184-198 peptide. The dominant 184-198 peptide itself had the same tolerogenic effects when given nasally lo rats daily, on the 4 days immediately preceding the induction of CIA. Two forms of CIA with acute and delayed disease onset were each modified by pre-treatment with the peptide. This study demonstrates that mucosal tolerance to CII can be induced by delivering it nasally in a way similar to that achieved previously by oral delivery, and that the use of an imnunodominanl epitope contained in a synthetic peptide will also suppress the immunologic and arthritic responses to collagen. [ABSTRACT FROM AUTHOR]

The effects of the immunomodulatory drug Linomide (LS-2616) have been investigated on two variants of collagen-induced arthritis (CIA) in Lewis rats. i.e. arthritis induced cither with heterologous (bovine) or with homologous (rat) collagen type II (CM). Treatment with Linomide from the day of immunization (prophylactic) had a mild ameliorative effect on the severity of arthritis in the heterologous CIA, while the homologous CIA was strongly augmented. In both models, Linomide treatment caused a more severe arthritis when given from onset of clinical signs of disease and onwards (therapeutic). Serum antibody levels to CII were significantly decreased by prophylactic Linomide treatment in rats immunized with heterologous CII, while elevated levels of anti-rat CII antibodies were seen in the homologous model. No effect on antibody levels was seen with the therapeutic treatment regime. The opposing effects of prophylactic treatment with Linomide in heterologous and homologous CIA indicate that the immune response to an autoantigen may be regulated differently from that to a foreign antigen. These results further strengthen the view that heterologous and homologous CIA should be regarded as separate experimental models, and that the studies on homologous CIA may represent a novel approach for future studies of autoimmune responses and evaluation of anti-rheumatic drugs. [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]