In vivo modulation of murine collagen induced arthritis

Modulation of IL-17 and Foxp3 expression in the prevention of autoimmune arthritis in mice

BACKGROUND

Rheumatoid Arthritis (RA) is a chronic immune mediated disease associated with deregulation of many cell types. It has been reported that different T cell subsets have opposite effects in disease pathogenesis, in particular Th17 and Treg cells.

METHODOLOGY AND FINDINGS

We investigated whether non-depleting anti-CD4 monoclonal antibodies, which have been reported as pro-tolerogenic, can lead to protection from chronic autoimmune arthritis in SKG mice--a recently described animal model of RA--by influencing the Th17/Treg balance. We found that non-depleting anti-CD4 prevented the onset of chronic autoimmune arthritis in SKG mice. Moreover, treated mice were protected from the induction of arthritis up to 60 days following anti-CD4 treatment, while remaining able to mount CD4-dependent immune responses to unrelated antigens. The antibody treatment also prevented disease progression in arthritic mice, although without leading to remission. Protection from arthritis was associated with an increased ratio of Foxp3, and decreased IL-17 producing T cells in the synovia. In vitro assays under Th17-polarizing conditions showed CD4-blockade prevents Th17 polarization, while favoring Foxp3 induction.

CONCLUSIONS

Non-depleting anti-CD4 can therefore induce long-term protection from chronic autoimmune arthritis in SKG mice through reciprocal changes in the frequency of Treg and Th17 cells in peripheral tissues, thus shifting the balance towards immune tolerance.

Autoimmune recognition of cartilage collagens

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

Cell-mediated transfer of collagen-induced arthritis in mice and its application to the analysis of the inhibitory effects of interferon-gamma and cyclophosphamide

We developed a convenient and reliable procedure for the cell-mediated passive transfer of type II collagen (CII)-induced arthritis (CA). Spleen cells from DBA/1 mice with CA were intravenously transferred into syngeneic recipient mice. Arthritis developed only in those recipients which had received whole-body x-irradiation (8 Gy) just before cell transfer and intraperitoneally given soluble CII without adjuvant immediately after transfer. Non-immunized splenocytes could not induce arthritis even in irradiated recipients given soluble CII. Development of arthritis depended on the number of cells transferred; 5 x 10(7) cells induced severe and long-lasting arthritis in every recipient approximately 10 days after transfer. Severity of this arthritis was clinically and histologically similar to classical CA in donors. Arthritogenic splenocytes were generated in donors no later than 20 days after priming with CII in Freund's complete adjuvant, when arthritis had yet to occur, and were detected for more than 5 weeks. One splenocyte population responsible for transferring arthritis was CD4+ T cells. We then applied this system to show that prophylactic treatment of CII-immunized mice with cyclophosphamide (CY, 7 mg/kg), but not interferon-gamma (IFN-gamma, 10(5) U/mouse), suppressed the arthritogenic ability of their spleen cells, although both treatments inhibited the development of CA. Treatment of recipients with IFN-gamma, however, inhibited the development of arthritis upon transfer with CII-immunized splenocytes. These results indicate that CY and IFN-gamma act at the induction and effector phases of arthritogenic lymphocytes, respectively. Thus, this system facilitates investigation of pathological mechanisms of CA, and of mechanisms of anti-arthritics.

Successful transfer of collagen-induced arthritis to severe combined immunodeficient (SCID) mice

We describe the adoptive transfer of erosive arthritis to an immunodeficient host. Spleen cells from arthritic DBA/1 mice (H-2q), immunized 4-6 weeks previously with bovine type II collagen in adjuvant, were transferred intraperitoneally into SCID mice (H-2d). SCID recipient mice also received native or denatured type II collagen (100 micrograms intraperitoneally) at the time of cell transfer. Arthritis developed in five out of five mice approximately 2 weeks after injection of cells plus native collagen, whereas animals injected with cells plus denatured collagen did not show any clinical or histological evidence of arthritis. The minimum graft size required for successful transfer of arthritis was established at 10(7) DBA/1 spleen cells. Histological examination of the joints of arthritic SCID recipient mice revealed synovitis, fibrosis and erosion of cartilage and underlying bone. Mean circulating levels of anti-type II collagen IgG were found to be significantly higher in mice injected with native collagen than those injected with denatured collagen (40 micrograms/ml and less than 1 microgram/ml, respectively). The ability to transfer collagen-induced arthritis adoptively should facilitate the study of the cellular requirement and pathological mechanisms involved in the induction of this arthropathy.

Treatment of rheumatoid arthritis with an anti-CD4 monoclonal antibody

The effect of treatment with a monoclonal antibody against the CD4 antigen present on T helper cells was studied in 10 patients with severe intractable rheumatoid arthritis. In an open trial, monoclonal antibody 16H5 was infused at a dosage of 0.3 mg/kg of body weight on 7 consecutive days. Studies of the kinetics demonstrated a drastic depletion of CD4+ cells, to as low as 25 cells/microliters, 1 hour after the first infusion. The subsequent recovery of the CD4+ cell numbers 24 hours after infusion did not reach initial levels, and after the full 7-day treatment cycle there was a significant reduction of the number of CD4+ cells (mean +/- SD 51 +/- 28%; P less than 0.02). There was a reduced or even inverse CD4:CD8 ratio, which generally persisted 3-4 weeks. Lymphocyte transformation assays demonstrated significantly reduced reactivity in 5 of the 9 patients who completed the 7-day course, whereas 4 individuals exhibited an unexpected elevation in the T cell response to mitogens and common antigens. Parallel laboratory studies showed a significant decrease in the erythrocyte sedimentation rate (P less than 0.05), rheumatoid factor titer (P less than 0.04), and total immunoglobulin values (P less than 0.01), as well as a reduction in C-reactive protein levels, in 7 of the 9 patients. Clinically, there was a significant reduction in the Ritchie articular index (P less than 0.05) and in the number of swollen joints (P less than 0.04). Adverse effects were urticaria in 2 patients, which led to withdrawal of therapy in 1 of them, and chills with fever, suggestive of a lymphokine release syndrome, in another 2 patients. Only low levels of human anti-mouse immunoglobulin antibodies developed (not exceeding 1.7 mg/liter). It was therefore possible to repeat the treatment cycle, achieving still better efficacy, in 4 of the patients (reductions in the Ritchie index and the number of swollen joints P less than 0.02). Our findings indicate that treatment with monoclonal antibodies against the CD4 antigen leads to immunomodulation which results in clinical benefits, at least during initial observation periods (up to 6 months postinfusion). However, it remains to be determined whether long-term remission can be induced with this therapeutic approach. The use of immunosuppressive therapies or repeated antibody treatments will have to be considered.

Estrogen induced suppression of collagen arthritis. V: Physiological level of estrogen in DBA/1 mice is therapeutic on established arthritis, suppresses anti-type II collagen T-cell dependent immunity and stimulates polyclonal B-cell activity

Immunization of castrated female DBA/1 mice with rat type II collagen (CII) induces severe polyarthritis with an onset 3-5 weeks after immunization and with 80-100% incidence. Estrogen treatment, inducing physiological 17 beta-estradiol (E2) levels, during a limited period before and after the immunization, or during another period before the expected onset of arthritis, delayed the arthritic onset by approximately 10 days but did not affect the incidence of severity of arthritis. Treatment with physiological doses of E2 after onset of arthritis decreased severity and duration of disease. The T-cell dependent anti-CII autoantibody response was suppressed if the E2 treatment was given immediately before and after CII immunization and was not significantly affected if E2 treatment was given after CII immunization. Neither the total anti-CII Ig levels nor the anti-CII IgG2a levels correlated with development of arthritis. We also titrated the serum levels of estrogen and recorded the vaginal smear response after injections of various doses of E2. This enabled us to work in a physiological range of estrogen levels, spanning the levels found at the end of pregnancy and those found during the normal estrous cycle. These levels were found to suppress antigen-specific T-cell functions but enhance certain B-cell activities since the delayed type hypersensitivity (DTH) reaction against CII was suppressed while the total number of splenic Ig-secreting cells increased. These findings suggest that estrogen in physiological doses is therapeutic for the development of collagen-induced arthritis and that estrogen exerts dualistic effects on the immune system by suppressing T-cell functions and stimulating certain B-cell activities. The suppressive effect on arthritis could not be explained by suppression of anti-CII autoantibody response and must therefore depend on other T-cell-mediated functions.

Arthritis in DBA/1 mice induced with passively transferred type II collagen immune serum. Immunohistopathology and serum levels of anti-type II collagen auto-antibodies

Arthritis was induced in DBA/1 mice by passive transfer of syngeneic anti-type II collagen (CII) serum concentrate. After transfer of serum containing 0.2 or 0.5 mg anti-CII auto-antibodies the first clinical signs of arthritis appeared 48 h after injection. Severe clinical arthritis was detected 96 h 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 after injection), the inflamed synovia were dominated by C3bi-receptor+ polymorphonuclear cells. In contrast to conventionally induced collagen arthritis (CIA), the inflammatory infiltrates, filling joint spaces and synovial tissue, were extensively dominated by polymorphonuclear cells, whereas macrophage-like cells expressing class II molecules and a few T cells were seen only in the periphery of the developing pannus. The anti-CII 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.