Effective treatment of established murine collagen-induced arthritis by systemic administration of dendritic cells genetically modified to express IL-4

Dendritic cell-based therapy in Type 1 diabetes mellitus

Dendritic cell (DC) immunotherapy is a clinical reality. Despite two decades of considerable data demonstrating the feasibility of using DCs to prolong transplant allograft survival and to prevent autoimmunity, only now are these cells entering clinical trials in humans. Type 1 diabetes is the first autoimmune disorder to be targeted for treatment in humans using autologous-engineered DCs. This review will highlight the role of DCs in autoimmunity and the manner in which they have been engineered to treat these disorders in rodent models, either via the induction of immune hyporesponsiveness, which may be cell- and/or antigen-specific, or indirectly by upregulation of other immune cell networks.

Development of dendritic cell-based immunotherapy for autoimmunity

Dendritic cells are professional antigen-presenting cells that maintain immune tolerance to self-antigens by deleting or controlling the pathogenicity of auto-reactive T-cells. Dendritic cell-based immunotherapies show great promise for the restoration of tolerance in autoimmune disease. Dendritic cells can be modified ex vivo to induce stable tolerogenic function and be used as cellular 'vaccines' or they can be targeted in vivo with sophisticated antigen delivery systems. Tolerogenic dendritic cells induce antigen-specific T-cell tolerance in vivo and have therapeutic effects in animal models of autoimmunity. The current challenge is to bring tolerogenic dendritic cell therapy to the clinic.

An optical imaging method to monitor stem cell migration in a model of immune-mediated arthritis

The objective of this work is to establish an optical imaging technique that would enable monitoring of the integration of mesenchymal stem cells (MSC) in arthritic joints. Our approach is based on first developing a labeling technique of MSC with the fluorescent dye DiD followed by tracking the cell migration kinetics from the spatial distribution of the DiD fluorescence in optical images (OI). The experimental approach involves first the in vitro OI of MSC labeled with DiD accompanied by fluorescence microscopy measurements to establish localization of the signal within the cells. Thereafter, DiD-labeled MSC were injected into polyarthritic, athymic rats and the signal localization within the experimental animals was monitored over several days. The experimental results indicate that DiD integrated into the cell membrane. DiD-labeled MSC localization in the arthritic ankle joints was observed with OI indicating that this method can be applied to monitor MSC in arthritic joints.

T cell receptor signaling induced by an analog peptide of type II collagen requires activation of Syk

We have previously described an analog peptide of type II collagen (CII) that can suppress collagen-induced arthritis (CIA). This analog peptide represents CII(245-270), the immunodominant epitope of CII, but with substitutions at 260, 261, and 263 - CII(245-270) (A(260), B(261), and N(263)) (A9). To elucidate the mechanisms responsible for suppression, we used mice transgenic for a collagen-specific T cell receptor (TCR). When we found that APCs pulsed with A9 failed to induce T cell phosphorylation of TCR-zeta and ZAP-70, we explored alternative signaling pathways. We determined that A9 instead induced phosphorylation of spleen tyrosine kinase (Syk). The importance of Syk was confirmed by the use of chemical Syk inhibitors, which blocked both cytokine secretion and activation of GATA-3 mediated by peptide A9. In summary, T cells use an alternative pathway in response to A9 that involves Syk. This novel T cell pathway may represent an important means for altering T cell phenotypes.

Type II collagen oral tolerance; mechanism and role in collagen-induced arthritis and rheumatoid arthritis

Oral tolerance means a diminished immune response to previously fed antigens. Repeated oral administrations of type II collagen (CII) induce oral tolerance and inhibit the development of collagen-induced arthritis (CIA). Dendritic cells (DCs) in the gut-associated lymphoid tissue (GALT) take up the CII and then present it to T cells to generate regulatory T cells (Tregs), which induce systemic immune tolerance to CII. Inhibitory cytokines, such as transforming growth factor (TGF)-beta and interleukin (IL)-10, and several immune regulatory molecules, including indoleamine 2,3-dioxygenase (IDO) and retinoic acid, play an important role in Treg generation. Each DC subset may play different roles, and CD11c+CD11b+DCs and IDO+DCs are important in the generation of antigen-inducible Tregs in CII oral tolerance. Upon stimulation with the antigen involved in its generation, Treg is activated and regulates the immune response through inhibitory cytokine production, cell-to-cell contact-dependent mechanisms, DC modification, and bystander suppression. The DCs and Tregs are deeply involved in oral tolerance through reciprocal interactions. Several clinical trials have been conducted in RA patients to examine the efficacy of CII oral tolerance. An understanding the mechanism of oral tolerance to CII would give clinicians new insights into the development of natural immune tolerance and new therapeutic approaches for the treatment of autoimmune diseases.

CTLA4-Ig modifies dendritic cells from mice with collagen-induced arthritis to increase the CD4+CD25+Foxp3+ regulatory T cell population

Cytotoxic T lymphocyte antigen-4 (CTLA4) and IgG fusion protein, CTLA4-Ig, is a therapeutic agent used for rheumatoid arthritis. It binds B7 molecules on dendritic cells (DCs) and thereby blocks B7/CD28 costimulatory interaction and inhibits effective T cell proliferation. However, the effect of CTLA4-Ig on the regulatory T cell (Treg) is still not known. In this study, we investigated the influence of CTLA4-Ig on the CD4+CD25+Foxp3+ Treg population in collagen-induced arthritis (CIA) mouse model. CTLA4-Ig suppressed CIA and increased the CD4+CD25+Foxp3+ Treg population in joint and spleen. When CD11c + DCs and CD4+T cells from CIA mice were cultured with anti-CD3, CTLA4-Ig increased the CD4+CD25 + Foxp3+ Treg population in a TGF-beta-dependent manner. When CD11c + DCs from CIA mice were treated with CTLA4-Ig and adoptively transferred into CIA-induced mice, arthritis did not develop in association with the increase in CD4+CD25+Foxp3+ Treg population. However, in CTLA4-Ig-untreated DC-transferred CIA mice, arthritis developed and then rapidly progressed. Our study demonstrated that CTLA4-Ig suppressed CIA by modifying DCs from CIA mice into tolerogenic DCs to increase the CD4+CD25+Foxp3+ Treg population and this seems to be the new immune regulatory mechanism of CTLA4-Ig.

Tolerizing DNA vaccines for autoimmune arthritis

Current therapies for rheumatoid arthritis (RA) and other autoimmune diseases non-specifically suppress immune function, and there is great need for fundamental approaches such as antigen-specific tolerizing therapy. In this paper we describe development of antigen-specific tolerizing DNA vaccines to treat collagen-induced arthritis (CIA) in mice, and use of protein microarrays to monitor response to therapy and to identify potential additional autoimmune targets for next generation vaccines. We demonstrate that tolerizing DNA vaccines encoding type II collagen (CII) reduced the incidence and severity of CIA. Atorvastatin, a statin drug found to reduce the severity of autoimmunity, potentiated the effect of DNA vaccines encoding CII. Analysis of cytokines produced by collagen-reactive T cells derived from mice receiving tolerizing DNA encoding CII, as compared to control vaccines, revealed reduced production of the pro-inflammatory cytokines IFN-gamma and TNF-alpha. Arthritis microarray analysis demonstrated reduced spreading of autoantibody responses in mice treated with DNA encoding CII. The development of tolerizing DNA vaccines, and the use of antibody profiling to guide design of and to monitor therapeutic responses to such vaccines, represents a promising approach for the treatment of RA and other autoimmune diseases.

Lymphoid-tissue-specific homing of bone-marrow-derived dendritic cells

Because of their potent immunoregulatory capacity, dendritic cells (DCs) have been exploited as therapeutic tools to boost immune responses against tumors or pathogens, or dampen autoimmune or allergic responses. Murine bone marrow-derived DCs (BM-DCs) are the closest known equivalent of the blood monocyte-derived DCs that have been used for human therapy. Current imaging methods have proven unable to properly address the migration of injected DCs to small and deep tissues in mice and humans. This study presents the first extensive analysis of BM-DC homing to lymph nodes (and other selected tissues) after intravenous and intraperitoneal inoculation. After intravenous delivery, DCs accumulated in the spleen, and preferentially in the pancreatic and lung-draining lymph nodes. In contrast, DCs injected intraperitoneally were found predominantly in peritoneal lymph nodes (pancreatic in particular), and in omentum-associated lymphoid tissue. This uneven distribution of BM-DCs, independent of the mouse strain and also observed within pancreatic lymph nodes, resulted in the uneven induction of immune response in different lymphoid tissues. These data have important implications for the design of systemic cellular therapy with DCs, and in particular underlie a previously unsuspected potential for specific treatment of diseases such as autoimmune diabetes and pancreatic cancer.

Lentiviral-mediated correction of MPS VI cells and gene transfer to joint tissues

Joint disease in mucopolysaccharidosis type VI (MPS VI) remains difficult to treat despite the success of enzyme replacement therapy in treating other symptoms. In this study, the efficacy of a lentiviral vector to transduce joint tissues and express N-acetylgalactosamine-4-sulphatase (4S), the enzyme deficient in MPS VI, was evaluated in vitro and the expression of beta-galactosidase was used to evaluate transduction in vivo. High viral copy number was achieved in MPS VI fibroblasts and 4-sulphatase activity reached 12 times the normal level. Storage of accumulated glycosaminoglycan was reduced in a dose dependent manner in both MPS VI skin fibroblasts and chondrocytes. Enzyme expression was maintained in skin fibroblasts for up to 41 days. Comparison of two promoters; the murine phosphoglycerate kinase gene promoter (pgk) and the myeloproliferative sarcoma virus long terminal repeat promoter (mpsv), demonstrated a higher level of marker gene expression driven by the mpsv promoter in both chondrocytes and synoviocytes in vitro. When injected into the rat knee, the expression of beta-galactosidase from the mpsv promoter was widespread across the synovial membrane and the fascia covering the cruciate ligaments and meniscus. No transduction of chondrocytes or ligament cells was observed. Transduction was maintained for at least 8 weeks after injection. These results indicate that the lentiviral vector can be used to deliver 4S to a range of joint tissues in vitro and efficiently transduce synovial cells and express beta-galactosidase in vivo.

Orthopedic gene therapy in 2008

Orthopedic disorders, although rarely fatal, are the leading cause of morbidity and impose a huge socioeconomic burden. Their prevalence will increase dramatically as populations age and gain weight. Many orthopedic conditions are difficult to treat by conventional means; however, they are good candidates for gene therapy. Clinical trials have already been initiated for arthritis and the aseptic loosening of prosthetic joints, and the development of bone-healing applications is at an advanced, preclinical stage. Other potential uses include the treatment of Mendelian diseases and orthopedic tumors, as well as the repair and regeneration of cartilage, ligaments, and tendons. Many of these goals should be achievable with existing technologies. The main barriers to clinical application are funding and regulatory issues, which in turn reflect major safety concerns and the opinion, in some quarters, that gene therapy should not be applied to nonlethal, nongenetic diseases. For some indications, advances in nongenetic treatments have also diminished enthusiasm. Nevertheless, the preclinical and early clinical data are impressive and provide considerable optimism that gene therapy will provide straightforward, effective solutions to the clinical management of several common debilitating disorders that are otherwise difficult and expensive to treat.

Gene therapy of the rheumatic diseases: 1998 to 2008

During the decade since the launch of Arthritis Research, the application of gene therapy to the rheumatic diseases has experienced the same vicissitudes as the field of gene therapy as a whole. There have been conceptual and technological advances and an increase in the number of clinical trials. However, funding has been unreliable and a small number of high-profile deaths in human trials, including one in an arthritis gene therapy trial, have provided ammunition to skeptics. Nevertheless, steady progress has been made in a number of applications, including rheumatoid arthritis and osteoarthritis, Sjögren syndrome, and lupus. Clinical trials in rheumatoid arthritis have progressed to phase II and have provided the first glimpses of possible efficacy. Two phase I protocols for osteoarthritis are under way. Proof of principle has been demonstrated in animal models of Sjögren syndrome and lupus. For certain indications, the major technological barriers to the development of genetic therapies seem to have been largely overcome. The translational research necessary to turn these advances into effective genetic medicines requires sustained funding and continuity of effort.

Dendritic cells and their potential implication in pathology and treatment of rheumatoid arthritis

Dendritic cells (DC) are the professional antigen presenting cells that protect us against invading organisms. On the other hand, they uphold tolerance thereby avoiding the initiation of autoimmunity. In performing these contrasting but essential tasks DC are unique and divide these processes in time and space. It is often thought that a loss of separation of these tasks underlies the breakthrough of tolerance leading to autoimmune conditions such as rheumatoid arthritis. In this review, we will focus on the evidence which points towards the implication of DC in the inflammatory process observed in RA and in experimental models of arthritis. Finally, we will conclude on future programs exploiting the capacity of DC to cure conditions such as RA.

LPS activation is required for migratory activity and antigen presentation by tolerogenic dendritic cells

Autoimmune pathologies are caused by a breakdown in self-tolerance. Tolerogenic dendritic cells (tolDC) are a promising immunotherapeutic tool for restoring self-tolerance in an antigen-specific manner. Studies about tolDC have focused largely on generating stable maturation-resistant DC, but few have fully addressed questions about the antigen-presenting and migratory capacities of these cells, prerequisites for successful immunotherapy. Here, we investigated whether human tolDC, generated with dexamethasone and the active form of vitamin D3, maintained their tolerogenic function upon activation with LPS (LPS-tolDC), while acquiring the ability to present exogenous autoantigen and to migrate in response to the CCR7 ligand CCL19. LPS activation led to important changes in the tolDC phenotype and function. LPS-tolDC, but not tolDC, expressed the chemokine receptor CCR7 and migrated in response to CCL19. Furthermore, LPS-tolDC were superior to tolDC in their ability to present type II collagen, a candidate autoantigen in rheumatoid arthritis. tolDC and LPS-tolDC had low stimulatory capacity for allogeneic, naïve T cells and skewed T cell polarization toward an anti-inflammatory phenotype, although LPS-tolDC induced significantly higher levels of IL-10 production by T cells. Our finding that LPS activation is essential for inducing migratory and antigen-presenting activity in tolDC is important for optimizing their therapeutic potential.

CCR9 expression defines tolerogenic plasmacytoid dendritic cells able to suppress acute graft-versus-host disease

Dendritic cells (DCs) are 'professional' antigen-presenting cells that are key in the regulation of immune responses. Here we characterize a unique subset of tolerogenic DCs that expressed the chemokine receptor CCR9 and migrated to the CCR9 ligand CCL25, a chemokine linked to the homing of T cells and DCs to the gut. CCR9(+) DCs were of the plasmacytoid DC (pDC) lineage, had an immature phenotype and rapidly downregulated CCR9 in response to maturation-inducing pDC-restricted Toll-like receptor ligands. CCR9(+) pDCs were potent inducers of regulatory T cell function and suppressed antigen-specific immune responses both in vitro and in vivo, including inhibiting acute graft-versus-host disease induced by allogeneic CD4(+) donor T cells in irradiated recipients. Our results identify a highly immunosuppressive population of pDCs present in lymphoid tissues.

AAV8-mediated gene transfer of interleukin-4 to endogenous beta-cells prevents the onset of diabetes in NOD mice

We have demonstrated the ability to deliver and express genes specifically in beta-cells for at least 6 months, using a murine insulin promoter (mIP) in a double-stranded, self-complementary AAV vector (dsAAV8-mIP). In this study, we evaluated the effects of dsAAV8-mIP-mediated delivery of interleukin 4 (mIL-4) to endogenous beta-cells in nonobese diabetic (NOD) mice. In 4-week-old NOD mice, the extent of gene transfer and expression in endogenous beta-cells after ip delivery of dsAAV8-mIP-enhanced green fluorescent protein (eGFP) was comparable to normal BALB/C mice. Further, after IP delivery of dsAAV8-mIP-IL4, expression of mIL-4 was detected in islets isolated from the treated mice and cultured. AAV8-mIP-mediated gene expression of mIL-4 in endogenous beta- cells of 4- and 8-week-old NOD mice prevented the onset of hyperglycemia in NOD mice and reduced the severity of insulitis. Moreover, expression of mIL-4 also maintained the level of CD4(+)CD25(+)FoxP3(+) cells, and adoptive transfer of splenocytes from nondiabetic dsAAV8-mIP-IL-4 mice to NODscid mice was able to block the diabetes induced by splenocytes co-adoptively transferred from nondiabetic dsAAV-mIP-eGFP mice. Taken together, these results demonstrate that local expression of mIL-4 in islets prevents islet destruction and blocks autoimmunity, partly through regulation of T-cell function.

Differential regulation of naïve and memory CD4+ T cells by alternatively activated dendritic cells

Promising immunotherapeutic tools for T cell-mediated pathologies are alternatively activated dendritic cells (aaDC), which exert their effect through the regulation and tolerization of T cells. As naïve and memory T cells have different susceptibilities to tolerogenic signals, it is important to understand the modulatory effects of aaDC on these T cell subsets. We have examined regulation of naïve and memory CD4⁺ T cells by human aaDC generated with dexamethasone, the active form of vitamin D3, 1α,25-dihydroxyvitamin D3, and LPS. Although aaDC induced low, primary, allogeneic responses by naïve and memory T cells, aaDC regulated the differentiation of these T cell subsets in a distinct manner. Naïve T cells primed by aaDC retained a strong, proliferative capacity upon restimulation but were skewed toward a low IFN-γ/high IL-10 cytokine profile. In contrast, memory T cells primed by aaDC became hyporesponsive in terms of proliferation and cytokine production. Induction of anergy in memory T cells by aaDC was not a result of the presence of CD25^hi regulatory T cells and could be partially reversed by IL-2. Both T cell subsets acquired regulatory activity and inhibited primary CD4 and CD8 responses. Addition of exogenous IL-12p70 during T cell priming by aaDC prevented anergy induction in memory T cells and cytokine polarization in naïve T cells, indicating that the lack of IL-12p70 is a key feature of aaDC. Our finding that aaDC differentially regulate naïve and memory T cells is important for understanding and maximizing the therapeutic potential of aaDC.

Use of dendritic cells in drug selection, development and therapy

BACKGROUND

Dendritic cells (DC) have the unique ability to induce immunity against tumors and various pathogens or to promote tolerance in autoimmunity and transplantation. Hence, they are central to the regulation of immune responses.

OBJECTIVE/METHODS

Due to the unique tolerogenic ability of DC, understanding some of the key molecules that regulate DC function may help with targeting the relevant signals in DC as therapeutic options for many disease conditions. DC are also targets of drugs, and many of the anti-inflammatory and pharmaceutical agents used to prevent autoimmunity or inhibit graft rejection interfere with DC function.

RESULTS/CONCLUSION

The drug-induced changes in DC may provide information for the selection of drugs and further drug discovery along with the use of DC as adjuvant in the treatment of autoimmunity and prevention of graft rejection in transplantation.

Multimodality imaging of T-cell hybridoma trafficking in collagen-induced arthritic mice: image-based estimation of the number of cells accumulating in mouse paws

Appropriate targeting of therapeutic cells is essential in adoptive cellular gene therapy (ACGT). Imaging cell trafficking in animal models and patients will guide development of ACGT protocols. Collagen type II (C-II)-specific T cell hybridomas are transduced with a lentivirus carrying a triple fusion reporter gene (TFR) construct consisting of a fluorescent reporter gene (RG), a bioluminescent RG (hRluc), and a positron emission tomography (PET) RG. Collagen-induced arthritic (CIA) mice are scanned with a bioluminescence imaging camera before and after implantation of various known cell quantities in their paws. Linear regression analysis yields equations relating two parameters of image signal intensity in mice paws to the quantity of hRluc expressing cells in the paws. Afterward, trafficking of intravenously injected cells is studied by quantitative analysis of bioluminescence images. Comparison of the average cell numbers does not demonstrate consistently higher accumulation of T-cell hybridomas in the paws with higher inflammation scores, and injecting more cells does not cause increased accumulation. MicroPET images illustrate above background signal in the inflamed paws and chest areas of CIA mice. The procedures described in this study can be used to derive equations for cells expressing other bioluminescent RGs and in other animal models.

Antigen-specific suppression of established arthritis in mice by dendritic cells deficient in NF-kappaB

OBJECTIVE

NF-kappaB inhibitors applied to animal models of rheumatoid arthritis (RA) demonstrate the important role of NF-kappaB in the production of mediators of inflammation in the joint and their antiinflammatory effects. Because NF-kappaB is involved in the differentiation, activation, and survival of almost all cells, its prolonged inhibition might have unwanted adverse effects. Therefore, we sought to apply NF-kappaB inhibitors more specifically, targeting dendritic cell (DC) differentiation, in order to influence the outcome of the autoimmune response, rather than to produce a broad antiinflammatory effect. We tested whether DCs treated with the NF-kappaB inhibitor BAY 11-7082 and exposed to arthritogenic antigen would suppress established arthritis in C57BL/6 mice.

METHODS

Antigen-induced arthritis was generated in C57BL/6 mice by injection of methylated bovine serum albumin (mBSA). After mBSA challenge, mouse knee joints were injected with antigen-exposed BAY 11-7082-treated DCs or with soluble tumor necrosis factor receptor (sTNFR). Intraarticular injection of interleukin-1 (IL-1) was used to induce disease flare.

RESULTS

Inflammation and erosion were suppressed in mice that received mBSA-exposed BAY 11-7082-treated DCs, but not in those that received keyhole limpet hemocyanin-exposed BAY 11-7082-treated DCs. Clinical improvement was dependent on IL-10 and was associated with antigen-specific suppression of the delayed-type hypersensitivity (DTH) reaction and switching of anti-mBSA antibody isotype from IgG2b to IgG1 and IgA. Suppression of the DTH reaction or arthritic disease was not impaired by concomitant administration of sTNFR. Suppression could be reversed with intraarticular administration of IL-1beta and could be restored by a second injection of mBSA-exposed BAY 11-7082-treated DCs.

CONCLUSION

BAY 11-7082-treated DCs induce antigen-specific immune suppression in this model of inflammatory arthritis, even after full clinical expression of the disease. Such DCs have potential as antigen-specific therapy for autoimmune inflammatory arthritis, including RA.

Immunoregulatory dendritic cells to prevent and reverse new-onset Type 1 diabetes mellitus

Herein, the authors provide an overview of where dendritic cells lie in the immunopathology of autoimmune Type 1 diabetes mellitus and how dendritic cell-based therapy may be usefully translated to treat and reverse the disease. The immunopathology of Type 1 diabetes mellitus offers a number of windows at which immunotherapy can be applied to delay, stop and even reverse the autoimmune processes, especially in light of the recent antibody-based accomplishment of improvement in residual beta-cell mass function. As in almost all cell-specific inflammatory processes, dendritic cells are central regulators of diabetes onset and progression. This realisation, along with accumulating data confirming a role for dendritic cells in maintaining and inducing tolerance in multiple therapeutic settings, has prompted a line of investigation to identify the most effective embodiments of dendritic cells for diabetes immunotherapy.

Effective Treatment of Inflammatory Disease Models with Exosomes Derived from Dendritic Cells Genetically Modified to Express IL-4

In this study, we demonstrate that genetically modified bone marrow-derived dendritic cells (DC) and exosomes derived from the DC, expressing either secreted IL-4 or membrane-bound IL-4, can reduce the severity and the incidence of established collagen-induced arthritis and inhibit inflammation of delayed-type hypersensitivity (DTH) in mice. The ability of the DC and DC-derived exosomes to suppress the DTH response was MHC class II and, in part, Fas ligand/Fas dependent. The DC-derived exosomes were internalized by CD11c(+) DC in the dermis at the site of injection and in the draining lymph node as well as by CD11c(+) DC and F4/80(+) macrophages in the spleen. Moreover, adoptive transfer of CD11c(+) or CD3(+) splenic cells from mice treated with exosomes showed significant reduction of footpad swelling in the DTH model. These results demonstrate that administration of DC/IL-4 or exosomes derived from DC/IL-4 are able to modulate the activity of APC and T cells in vivo through a MHC class II and partly Fas ligand/Fas-dependent mechanism, resulting in effective treatment of established collagen-induced arthritis and suppression of the DTH inflammatory response. Thus, APC-derived exosomes could be used therapeutically for the treatment of autoimmune disease and inflammatory disorders.

Infusion of Stably Immature Monocyte-Derived Dendritic Cells Plus CTLA4Ig Modulates Alloimmune Reactivity in Rhesus Macaques

BACKGROUND

Immature dendritic cells (DC) can promote long-term transplant survival in rodents. We assessed the impact of stably immature, donor-derived DC on alloimmune reactivity in rhesus macaques.

METHODS

CD14 monocytes isolated from leukapheresis products of Macacca mulatta were cultured in granulocyte-macrophage colony stimulating factor plus interleukin (IL)-4+/-vitamin (vit) D3, and IL-10. Major histocompatibility complex class II and cosignaling molecule expression was determined on CD11c cells by flow cytometry. T-cell allostimulatory capacity of the DC, including DC exposed to proinflammatory cytokines, was determined in mixed leukocyte reaction. To test their influence in vivo, purified DC were infused intravenously into allogeneic recipients, either alone or followed by CTLA4Ig, 24 hr later. Proliferative responses of recipient CFSE-labeled T cells to donor or third party DC, cytokine production by stimulated T cells, and circulating alloantibody levels were determined by flow cytometry, up to 100 days postinfusion.

RESULTS

VitD3/IL-10-conditioned, monocyte-derived DC were resistant to maturation and failed to induce allogeneic T cell proliferation in vitro. After their infusion, an increase in anti-donor and anti-third party T-cell reactivity was observed, that subsequently subsided to fall significantly below pretreatment levels (by day 56) only in animals also given CTLA4Ig. No increase in circulating immunoglobulin (Ig) M or IgG anti-donor alloantibody titers compared with pretreatment values was detected. With DC+CTLA4Ig infusion, alloreactive IL-10-producing T cells were prevalent in the circulation after day 28.

CONCLUSIONS

Maturation-resistant rhesus DC infusion is well-tolerated. DC+CTLA4Ig infusion modulates allogeneic T-cell responses and results in hyporesponsiveness to donor and third party alloantigens.

Interleukin-17 as a molecular target in immune-mediated arthritis: immunoregulatory properties of genetically modified murine dendritic cells that secrete interleukin-4

OBJECTIVE

Our previous studies have shown that murine dendritic cells (DCs) genetically modified to express interleukin-4 (IL-4) reduce the incidence and severity of murine collagen-induced arthritis. The present studies were performed to assess the immunoregulatory mechanisms underlying this response, by assessing the effects of IL-4 DCs on cytokine production by subsets of T helper cells.

METHODS

Male DBA mice ages 6-8 weeks old were immunized with type II collagen. Splenic T cells obtained during the initiation phase and the end stage of arthritis were cultured with IL-4 DCs or untransduced DCs in the presence of collagen rechallenge. Interferon-gamma (IFNgamma) and IL-17 responses were measured. Antibodies to IL-4, IL-12, and IL-23, and recombinant IL-4, IL-12, and IL-23 were used to further study the regulation of T cell cytokine production by IL-4 DCs.

RESULTS

Splenic T cells obtained during the initiation phase of arthritis produced less IL-17 when cultured in the presence of IL-4 DCs, despite their production of increased quantities of other proinflammatory cytokines (IFNgamma and tumor necrosis factor). T cell IL-17 production after collagen rechallenge was not inhibited by a lack of IL-23, since IL-4-mediated suppression of IL-17 was not reconstituted by IL-23, an otherwise potent inducer of IL-17 production by T cells. Although IL-4 DCs can produce increased quantities of IL-12 and IFNgamma, suppression of IL-17 production by IL-4 DCs was independent of both. While IL-17 production by T cells obtained during the initiation phase of arthritis was regulated by IL-4 DCs, IL-17 production by T cells obtained during end-stage arthritis was not altered.

CONCLUSION

Our data suggest that IL-4 DCs exert a therapeutic effect on collagen-induced arthritis by targeting IL-17. IL-17 suppression by IL-4 DCs is robust and is not reversed by IL-23. Timing might be important in IL-17-targeted therapy, since IL-17 production by T cells obtained during end-stage arthritis did not respond to suppression by IL-4 DCs.

Analog peptides of type II collagen can suppress arthritis in HLA-DR4 (DRB1*0401) transgenic mice

Rheumatoid arthritis (RA) is an autoimmune disease associated with the recognition of self proteins secluded in diarthrodial joints. We have previously established that mice transgenic for the human DR genes associated with RA are susceptible to collagen-induced arthritis (CIA) and we have identified a determinant of type II collagen (CII(263-270)) that triggers T-cell immune responses in these mice. We have also determined that an analog of CII(263-270) would suppress disease in DR1 transgenic mice. Because the immunodominant determinant is the same for both DR1 transgenic and DR4 transgenic mice, we attempted to determine whether the analog peptide that was suppressive in DR1 transgenic mice would also be effective in suppressing CIA in DR4 transgenic mice. We treated DR4 transgenic mice with two analog peptides of CII that contained substitutions in the core of the immunodominant determinant: CII(256-276) (F263N, E266D) and CII(256-270) (F263N, E266A). Mice were observed for CIA, and T-cell proliferative responses were determined. Either peptide administered at the time of immunization with CII significantly downregulated arthritis. Binding studies demonstrated that replacement of the phenylalanine residue in position 263 of the CII peptide with asparagine significantly decreased the affinity of the peptide for the DR4 molecule. In contrast, replacement of the glutamic acid residue in position 266 with aspartic acid or with alanine had differing results. Aspartic acid reduced the affinity (35-fold) whereas alanine did not. Both peptides were capable of suppressing CIA. With the use of either peptide, CII(256-276) (F263N, E266D) or CII(256-270) (F263N, E266A), the modulation of CIA was associated with an increase in T-cell secretion of IL-4 together with a decrease in IFN-gamma. We have identified two analog peptides that are potent suppressors of CIA in DR4 transgenic mice. These experiments represent the first description of an analog peptide of CII recognized by T cells in the context of HLA-DR4 that can suppress autoimmune arthritis.

Application of cellular gene therapy for rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease characterized by persistent inflammation of joints resulting in progressive destruction of cartilage and bone. Recently, biological agents that suppress the activities of proinflammatory cytokines have shown efficacy as antirheumatic drugs, but require frequent administration, and often result in systemic immune suppression. Thus, gene transfer approaches are being developed as an alternative approach for targeted, more efficient, and sustained delivery of inhibitors of inflammatory cytokines as well as other therapeutic agents. Several gene therapy approaches have been established in preclinical animal models. In these models, autoantigen-specific T cells have been demonstrated to be ideal gene delivery vehicles for the local delivery of “immunoregulatory molecules” because these cells have tissue-specific homing and retention properties. Indeed, bioluminescence studies in an animal model of inflammatory arthritis revealed that these cells accumulated in and remained in inflamed joints. Transfer of genetically modified dendritic cells (DCs) may also have interesting effects. We conclude that modifying antigen-specific T cells or autologous DCs by retroviral transduction for local expression of regulatory proteins is a promising therapeutic strategy for the treatment of RA.

Activating and inhibitory FcγRs in autoimmune disorders

Autoimmune disorders are characterized by the destruction of self-tissues by the immune system. Multiple checkpoints are in place to prevent autoreactivity under normal circumstances. Coexpression of activating and inhibitory Fc receptors (FcR) represents such a checkpoint by establishing a threshold for immune cell activation. In many human autoimmune diseases, however, balanced FcR expression is disturbed. Analysis of murine model systems provides strong evidence that aberrant FcR expression can result in uncontrolled immune responses and the initiation of autoimmune disease. This review will summarize this data and explain how this information might be used to better understand human autoimmune diseases and to develop novel therapeutic strategies.

Salmonella typhimurium infection in nonobese diabetic mice generates immunomodulatory dendritic cells able to prevent type 1 diabetes

Infection, commencing across a wide age range, with a live, attenuated strain of Salmonella typhimurium, will halt the development of type 1 diabetes in the NOD mouse. The protective mechanism appears to involve the regulation of autoreactive T cells in a manner associated with long lasting changes in the innate immune compartment of these mice. We show in this study that autoreactive T cell priming and trafficking are altered in mice that have been infected previously by S. typhimurium. These changes are associated with sustained alterations in patterns of chemokine expression. We find that small numbers of dendritic cells from mice that have been previously infected with, but cleared all trace of a S. typhimurium infection are able to prevent the development of diabetes in the highly synchronized and aggressive cyclophosphamide-induced model. The effects we observe on autoreactive T cell trafficking are recapitulated by the immunomodulatory dendritic cell transfers in the cyclophosphamide model.

Dendritic cells transduced with SOCS-3 exhibit a tolerogenic/DC2 phenotype that directs type 2 Th cell differentiation in vitro and in vivo

Dendritic cells (DCs) have been suggested to direct a type of Th differentiation through their cytokine profile, e.g., high IL-12/IL-23 for Th1 (named DC1/immunogenic DCs) and IL-10 for Th2 (DC2/tolerogenic DCs). Suppressor of cytokine signaling (SOCS)-3 is a potent inhibitor of Stat3 and Stat4 transduction pathways for IL-23 and IL-12, respectively. We thus hypothesize that an enhanced SOCS-3 expression in DCs may block the autocrine response of IL-12/IL-23 in these cells, causing them to become a DC2-type phenotype that will subsequently promote Th2 polarization of naive T cells. Indeed, in the present study we found that bone marrow-derived DCs transduced with SOCS-3 significantly inhibited IL-12-induced activation of Stat4 and IL-23-induced activation of Stat3. These SOCS-3-transduced DCs expressed a low level of MHC class II and CD86 on their surface, produced a high level of IL-10 but low levels of IL-12 and IFN-gamma, and expressed a low level of IL-23 p19 mRNA. Functionally, SOCS-3-transduced DCs drove naive myelin oligodendrocyte glycoprotein-specific T cells to a strong Th2 differentiation in vitro and in vivo. Injection of SOCS-3-transduced DCs significantly suppressed experimental autoimmune encephalomyelitis, a Th1 cell-mediated autoimmune disorder of the CNS and an animal model of multiple sclerosis. These results indicate that transduction of SOCS-3 in DCs is an effective approach to generating tolerogenic/DC2 cells that then skew immune response toward Th2, thus possessing therapeutic potential in Th1-dominant autoimmune disorders such as multiple sclerosis.

Arthritis induced with cartilage-specific antibodiesis IL-4-dependent

It is widely believed that IL-4 exerts its influence by profiling the immune response during priming and expansion of immune cells, and thereby modulates the outcome of chronic inflammation. In the present investigation, collagen antibody-induced arthritis (CAIA) was used to delineate the role of IL-4 in a T cell-independent inflammatory phase. Mice predisposed to Th2 cytokines (BALB/c and STAT4-deficient mice) developed a more severe arthritis than mice biased towards Th1 cytokines (C57BL/6 and STAT6-deficient mice). Reduced incidence of CAIA was observed in IL-4-deficient mice compared to control littermates. Infiltrating cells in the paws of IL-4-sufficient mice had increased osteoclast activity and tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta secretion. Massive infiltration of granulocytes and joint and cartilage damage were present in arthritic paws. Depletion of IL-4 suppressed CAIA, which was abrogated by IFN-gamma neutralization. IL-1R- and IL-1RTNFR-deficient mice were completely resistant to CAIA. Thus, IL-4 promotes an antibody-mediated and TNF-alpha/IL-1beta-dependent inflammation in vivo.

The limitation of IL-10-exposed dendritic cells in the treatment of experimental autoimmune myasthenia gravis and myasthenia gravis

Dendritic cells (DC) are highly specialized antigen presenting cells that play critical roles as instigators and regulators of immune responses including B cell function, antibody synthesis and isotype switch. In this study, we compared immunotherapeutic effect of IL-10-treated DC (IL-10-DC) via both intraperitoneal (i.p.) and subcutaneous (s.c.) delivery in rats with incipient experimental autoimmune myasthenia gravis (EAMG). Spleen DC were isolated from onset of EAMG on day 39 post-immunization, exposed in vitro to IL-10, and then injected into incipient EAMG at dose of 1 x 10(6) cells/rat on day 5 after immunization. Intraperitoneal administration of IL-10-DC suppressed clinical scores, anti-acetylcholine receptors (AChR) antibody secreting cells, antigen-specific IL-10/IFN-gamma production and T cell proliferation compared to control EAMG rats. Importantly, IL-10-DC, if given by s.c. route, failed to ameliorate clinical sign of EAMG. Simultaneously, T cell proliferation, anti-AChR antibody secreting cells and IL-10/IFN-gamma production had no alteration, as compared to control EAMG rats. Both in vitro and in vivo experiments showed that treatment of IL-10 inhibited the migration of DC toward MIP-3beta and lymph node, indicating that in vitro manipulation of DC with IL-10 alters the migration of DC that influences the therapeutic effect in the treatment of autoimmune diseases. In MG patients, neither the improvement of clinical symptom nor the alteration of immunological parameter was observed through s.c. delivery of IL-10-DC, suggesting the limitation of IL-10-DC in the treatment of MG patients.

Antigen-induced, tolerogenic CD11c+,CD11b+ dendritic cells are abundant in Peyer's patches during the induction of oral tolerance to type II collagen and suppress experimental collagen-induced arthritis

OBJECTIVE

Although oral tolerance is a well-known phenomenon, the role of dendritic cells (DCs) is not well characterized. This study was conducted to better understand the differential role played by each Peyer's patch DC subset in the induction of oral tolerance to type II collagen (CII) in murine collagen-induced arthritis (CIA).

METHODS

CII was fed 6 times to DBA/1 mice beginning 2 weeks before immunization, and the effect on arthritis was assessed. We compared the proportion of CD11c+,CD11b+ DCs and CD11c+,CD8alpha+ DCs in the Peyer's patches of CII-fed tolerized and phosphate buffered saline-fed nontolerized mice after the induction of CIA. The immunosuppressive properties of each DC subset were determined using fluorescence-activated cell sorter analysis for intracellular interleukin-10 (IL-10) and IL-12 and mixed lymphocyte culture. The ability of each DC subset to induce CD4+,CD25+ T regulatory cells was also examined. Mice were injected with CII-pulsed CD11c+,CD11b+ DCs isolated from Peyer's patches of tolerized mice, and the effect on CIA was examined.

RESULTS

The severity of arthritis was significantly lower in tolerized mice. The proportion of CD11c+,CD11b+ DCs was increased in the Peyer's patches of tolerized mice and those DCs exhibited immunosuppressive characteristics, such as increased IL-10 production, inhibition of T cell proliferative responses to CII, and CD4+,CD25+ regulatory T cell induction. Furthermore, the CD11c+,CD11b+ DCs suppressed the severity of arthritis upon adoptive transfer.

CONCLUSION

Our observations demonstrate that CD11c+,CD11b+ DCs, which are abundant in Peyer's patches during the induction of oral tolerance to CII, are crucial for the suppression of CIA and could be exploited for immunotherapy of autoimmune diseases.

Exosomes Derived from Genetically Modified DC Expressing FasL Are Anti-inflammatory and Immunosuppressive

We previously have demonstrated the ability of primary murine bone marrow-derived DC (BM-DC), genetically modified by adenoviral infection to express FasL, to inhibit progression of established collagen-induced arthritis (CIA) following systemic delivery. Here we demonstrate that exosomes derived from genetically modified BM-DC expressing FasL are able to inhibit inflammation in a murine footpad model of delayed-type hypersensitivity (DTH). Local administration of exosomes derived from DC expressing FasL (Exo/FasL) as well as the parental DC/FasL resulted in a significant reduction in swelling in both the treated and the untreated distal paw. However, both the DC/FasL and the Exo/FasL were unable to suppress the DTH response in lpr (Fas-deficient) mice. Gene transfer of FasL to BM-DC from gld (FasL-deficient) mice resulted in restoration of the ability of DC as well as DC-derived exosomes to suppress DTH. The ability of DC-derived exosomes and DC to suppress DTH responses was antigen specific and MHC class II dependent, but class I independent. The injected exosomes were found to be internalized into CD11c(+) cells at the site of injection and in the draining popliteal lymph node. Systemic injection of exosome/FasL into mice with established CIA resulted in significant disease amelioration. These results demonstrate that both systemic and local administration of exosomes derived from FasL-expressing DC are able to suppress antigen-specific immune responses through an MHC class II-dependent pathway, resulting in effective and sustained treatment of established collagen-induced arthritis and suppression of the DTH inflammatory response. These results suggest that DC/FasL-derived exosomes could be used clinically for the treatment of inflammatory and autoimmune diseases.

The 3rd International Meeting on Gene Therapy in Rheumatology and Orthopaedics

The 3rd International Meeting on Gene Therapy in Rheumatology and Orthopaedics was held in Boston, Massachusetts, USA in May 2004. Keystone lectures delivered by Drs Joseph Glorioso and Inder Verma provided comprehensive, up-to-date information on all major virus vectors. Other invited speakers covered the application of gene therapy to treatment of arthritis, including the latest clinical trial in rheumatoid arthritis, as well as lupus and Sjögren's syndrome. Applications in mesenchymal stem cell biology, tissue repair, and regenerative medicine were also addressed. The field has advanced considerably since the previous meeting in this series, and further clinical trials seem likely.

Cytokine production by dendritic cells genetically engineered to express IL-4: induction of Th2 responses and differential regulation of IL-12 and IL-23 synthesis

Dendritic cells (DCs) retrovirally transduced with IL-4 have recently been shown to inhibit murine collagen-induced arthritis and associated Th1 immune responses in vivo, but the mechanisms that underly these effects are not yet understood. In this report we demonstrate that IL-4-transduced DCs loaded with antigen led to lower T cell production of IFN-gamma, increased production of IL-4, and an attenuated, delayed type hypersensitivity response. We hypothesized that the ability of such DCs to regulate the Th1 immune response in vivo depends in part on their capacity to produce IL-12 and IL-23. Quantitative mRNA analysis revealed that IL-4-transduced DCs stimulated with CD40 ligand expressed higher levels of IL-12p35 mRNA, but lower levels of mRNA for IL-23p19 and the common subunit p40 found in both IL-12 and IL-23, compared with control DCs. These results, which indicate that expression of the IL-12 and IL-23 subunits is differentially regulated in IL-4-transduced DCs, were confirmed by ELISA of the IL-12 and IL-23 heterodimers. Thus, therapeutic suppression of Th1 -mediated autoimmunity (as recently shown in murine collagen-induced arthritis) and induction of Th2 responses in vivo by IL-4-transduced DCs occurs despite their potential to produce increased levels of IL-12, but could reflect, in part, decreased production of IL-23.

Targeted gene therapy of autoimmune diseases: advances and prospects

Idealized gene therapy of autoimmune diseases would mean getting the right drug to the right place at the right time to affect the right mechanism of action. In other words, a specific gene therapy strategy needs to have functional, spatial and temporal specificity. Functional specificity implies targeting the cellular, molecular and/or genetic mechanisms relevant to the disease, without affecting nondiseased organs or tissues through mechanisms that cause adverse effects. Spatial specificity means the delivery of the therapeutic agent exclusively to sites and cells that are relevant to the disease. Temporal specificity is, in principle, synonymous with controlled on-demand expression of the therapeutic gene and thus represents a major safety feature. This article reviews recent advances in strategies to use gene therapy in the treatment of autoimmune diseases.

Plasmacytoid dendritic cell precursors induce allogeneic T-cell hyporesponsiveness and prolong heart graft survival

Dendritic cell (DC) precursors were propagated from C57BL/10 (B10; H2b) mouse bone marrow in fms-like tyrosine kinase 3 ligand. Cosignaling molecule (B7-1/B7-2 and B7-H1) expression and stimulatory capacity of precursor (pre)-plasmacytoid (p)DC (CD11c+B220+CD11b-CD19-) and classic myeloid DC (MDC) for allogeneic (C3H; H2k) T cells were compared. Unstimulated pre-pDC exhibited very low levels of surface MHC class II and classic costimulatory molecules (B7-1/B7-2), whereas a minor population expressed B7-H1 at levels higher than on MDC. The pre-pDC were ineffective T-cell stimulators and induced nonspecific hyporesponsiveness to rechallenge with donor alloantigens in vitro and in vivo. Following stimulation with CpG-oligonucleotide (CpG-ODN), B7 molecule expression was upregulated on pre-pDC, however the ratio between coinhibitory (B7-H1) and costimulatory (B7-1/B7-2) signals was much higher (five- to six-fold) on pre-pDC than MDC. Blockade of B7-H1 expression on pDC increased their T-cell allostimulatory capacity significantly. A single preoperative infusion of C3H hosts with pre-pDC prolonged B10 heart graft survival significantly but nonspecifically compared with untreated mice (median survival times 22 vs. 9 days, respectively). Thus, pre-pDC of donor origin have potential to regulate T-cell responses to alloantigens and can prolong organ graft survival.

Exosomes Derived from IL-10-Treated Dendritic Cells Can Suppress Inflammation and Collagen-Induced Arthritis

We have demonstrated previously that local, adenoviral-mediated gene transfer of viral IL-10 to a single joint of rabbits and mice with experimental arthritis can suppress disease in both the treated and untreated contralateral joints. This contralateral effect is mediated in part by APCs able to traffic from the treated joint to lymph nodes as well as to untreated joints. Moreover, injection of dendritic cells (DC) genetically modified to express IL-4 or Fas ligand was able to reverse established murine arthritis. To examine the ability of exosomes derived from immunosuppressive DCs to reduce inflammation and autoimmunity, murine models of delayed-type hypersensitivity and collagen-induced arthritis were used. In this study, we demonstrate that periarticular administration of exosomes purified from either bone marrow-derived DCs transduced ex vivo with an adenovirus expressing viral IL-10 or bone marrow-derived DCs treated with recombinant murine IL-10 were able to suppress delayed-type hypersensitivity responses within injected and untreated contralateral joints. In addition, the systemic injection of IL-10-treated DC-derived exosomes was able suppress the onset of murine collagen-induced arthritis as well as reduce severity of established arthritis. Taken together, these data suggest that immature DCs are able to secrete exosomes that are involved in the suppression of inflammatory and autoimmune responses. Thus DC-derived exosomes may represent a novel, cell-free therapy for the treatment of autoimmune diseases.

Interleukin-4 cellular gene therapy and osteoprotegerin decrease inflammation-associated bone resorption in collagen-induced arthritis

To evaluate the respective action of IL-4, an anti-inflammatory cytokine, and OPG, an inhibitor of bone resorption, on the inflammatory process and the associated bone resorption in collagen-induced arthritis (CIA). After CIA induction, DBA/1 mice were treated with OPG or with IL-4 DBA/1 transfected fibroblasts or both OPG + IL-4. CIA significantly improved in IL-4 groups. OPG had no effect on arthritis clinical scores but histologic scores were reduced in OPG, IL-4, and OPG + IL-4 groups vs. nontreated CIA mice. OPG increased significantly BMD and decreased by 45% D-pyridinolin levels. Moreover association of IL-4 and OPG exerted an additive effect of BMD and resorption marker (-68%). Production of IFN-gamma in the supernatants of spleen cells was reduced in IL-4 treated mice. OPG had a moderate effect on IFN-gamma, but potentiated the inhibitory effect of IL-4. OPG and IL-4 prevent bone loss in CIA-mice model and could have additive effects on IFN-gamma secretion.

Efficacy of peripheral tolerance induced by dendritic cells is dependent on route of delivery

Previous studies have demonstrated that the route of delivery of dendritic cells (DC) is an important variable in eliciting anti-tumor immunity. In contrast, little is known about different routes of DC administration to influence peripheral tolerance in autoimmune diseases. Here we compared therapeutic effect of splenic IFN-gamma-modified-DC (IFN-gamma-DC) in actively induced experimental allergic encephalomyelitis (EAE) by different routes of DC delivery. Following subcutaneous (s.c.) injection, IFN-gamma-DC effectively suppressed clinical signs of EAE, whereas intravenous (i.v.) injection did not inhibit clinical signs of EAE. Compared to s.c. injection, i.v. injection of IFN-gamma-DC failed to mediate T cell responses, but stimulated anti-MBP antibody production and upregulated pro-inflammatory IL-1beta, IFN-gamma and TNF-alpha as well as RANTES expression which may contribute to the accumulation of inflammatory cells within the central nervous system. These results suggest that the administration route of DC should be considered as an important factor for DC-based immunotherapy in autoimmune diseases.

Characterization of allergen-specific monocyte-derived dendritic cells generated from monocytes by a single-step procedure: effect on naïve and memory T cells

BACKGROUND

Dendritic cells are one of the most potent antigen-presenting cells and when pulsed with allergen can modulate allergen-specific T-cell responses. We sought to establish a single-step method by which to generate allergen-specific monocyte-derived dendritic cells (MoDCs).

METHODS

Dermatophagoides farinae (Df)-prepulsed MoDCs were generated from monocytes by culturing with Df in the presence interleukin (IL)-4, granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumour necrosis factor (TNF)-alpha simultaneously. Df-prepulsed MoDC were incubated with autologous naive and memory T cells in the absence of recall antigen, then proliferation and cytokine production by T cells was determined.

RESULTS

Generation of allergen-prepulsed MoDCs was confirmed by examining expression of surface molecules. Df-prepulsed MoDC selectively induced proliferation of Df-specific T cells in the absence of recall antigen. Under these conditions, Df-prepulsed MoDCs augmented but did not alter the cytokine production profile. In addition, Df-prepulsed MoDCs activated naive T cells leading to proliferation and selective production of IFN-gamma in allergic patients but not in healthy subjects.

CONCLUSIONS

These results suggest that Df-prepulsed MoDC generated from monocytes by a simple single-step manipulation can induce Df-specific cellular responses from both naive and memory T cells in the absence of recall antigen, and these cells potentially can be utilized as immune adjuvants in allergen-specific immunotherapy.

The 2003 Nicolas Andry Award. Orthopaedic gene therapy

We review progress in the field of orthopaedic gene therapy since the concept of using gene transfer to address orthopaedic problems was initiated approximately 15 years ago. The original target, arthritis, has been the subject of two successful Phase I clinical trials, and additional human studies are pending in rheumatoid arthritis and osteoarthritis. The repair of damaged musculoskeletal tissues also has proved to be a fruitful area of research, and impressive enhancement of bone healing has been achieved in preclinical models. Rapid progress also is being made in the use of gene transfer to improve cartilage repair, ligament healing, and restoration of various additional tissues, including tendon and meniscus. Other applications include intervertebral disc degeneration, aseptic loosening, osteoporosis, genetic diseases, and orthopaedic tumors. Of these various orthopaedic targets of gene therapy, tissue repair is likely to make the earliest clinical impact because it can be achieved with existing technology. Tissue repair may become one of the earliest clinical successes for gene therapy as a whole. Orthopaedics promises to be a leading discipline for the use of human gene therapy.

Antigen-specific immunomodulation of collagen-induced arthritis with tumor necrosis factor-stimulated dendritic cells

OBJECTIVE

Dendritic cells (DCs) are crucial for the initiation of T cell immunity and therefore play an important role in the initiation and regulation of immune responses in arthritis. Full mobilization of effector T cells depends on the proper maturation of DCs. Current evidence indicates that the type of T cell response induced is crucially dependent on the activation status of the DCs. In this study, we explored the immunologic effects of differentially matured DCs on the development of collagen-induced arthritis (CIA).

METHODS

Bone marrow-derived DCs were cultured in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF). Before immunization with bovine type II collagen (CII) protein, mice were repeatedly injected with DCs that had been pulsed with CII. Immature, semimature, or fully mature DCs were injected. Mice were boosted on day 21 after CII immunization, and the disease course was monitored.

RESULTS

While vaccination with immature or lipopolysaccharide-activated DCs had no significant effect on the disease course, administration of antigen-loaded, tumor necrosis factor (TNF)-modulated DCs propagated in GM-CSF with or without interleukin-4 resulted in a delayed onset of arthritis and a lower clinical score. The response was antigen-specific, since TNF-treated DCs pulsed with a control antigen did not modify the disease course. A specific decrease in the collagen-specific "Th1-associated" IgG2a response was observed, whereas IgG1 titers were unaffected.

CONCLUSION

CIA can be prevented through vaccination with TNF-matured DCs in an antigen-specific manner. These findings provide a rationale for immunotherapy using DCs in rheumatoid arthritis.

Multiple facets of macrophages in renal injury

Macrophage infiltration is a common feature of renal disease and their presence has been synonymous with tissue damage and progressive renal failure. More recently work has focused on the heterogeneity of macrophage activation and in particular their ability to curtail inflammation and restore normal function. This has led to the view that it is macrophage function rather than their number that is important in determining the outcome of inflammatory disease. This review will focus on the pathways that regulate macrophage infiltration and activation and how these could be manipulated to control renal inflammatory disease. In particular, the ability of specific cell surface receptors and intracellular signaling pathways to control macrophage activation and how macrophages can be genetically manipulated to develop properties that favor resolution over ongoing injury.

Protection against collagen-induced arthritis by electrotransfer of an expression plasmid for the interleukin-4

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease, leading to cartilage and bone destruction. We investigated whether the electrotransfer of IL-4 DNA could regulate the disease progress of murine collagen-induced arthritis (CIA). The maximum serum level of mIL-4 was measured by 340 pg/ml on day 1 following DNA transfer. The onset of severe CIA and the degree of synovitis and cartilage erosion were significantly reduced in mice treated with IL-4 DNA (P<0.05). The beneficial effect of IL-4 gene transfer lasted for at least 17 days subsequent to treatment. The expression of IL-1beta was considerably decreased in the paws by IL-4 DNA transfer (P<0.01). On the contrary, the ratio of TIMP2 to MMP2 significantly increased in the IL-4 DNA-treated group (P<0.01). These data demonstrated that electroporation-mediated gene transfer could provide a new approach as an IL-4 therapy for autoimmune arthritis.

Increased expression of CCL18, CCL19, and CCL17 by dendritic cells from patients with rheumatoid arthritis, and regulation by Fc gamma receptors

BACKGROUND

Dendritic cells (DC) have a role in the regulation of immunity and tolerance, attracting inflammatory cells by the production of various chemokines (CK). Fc gamma receptors (Fc gamma R) may be involved in regulation of the DC function.

OBJECTIVE

To assess the expression of CK by immature (iDC) and mature DC (mDC) and its regulation by Fc gamma R in patients with RA and healthy donors (HC).

METHODS

Expression of CK by DC from patients with RA and from HC was determined by real time quantitative PCR and ELISA. DC were derived from monocytes following standardised protocols. To study the potential regulation by Fc gamma R, iDC were stimulated with immune complexes (IC) during lipopolysaccharide (LPS) induced maturation. The presence of CK was studied in synovial tissue from patients with RA, osteoarthritis, and healthy subjects by RT-PCR and immunohistochemistry.

RESULTS

iDC from patients with RA had markedly increased mRNA levels of the CK CCL18 and CXCL8. Upon maturation with LPS, expression of CCL18, CCL19, CXCL8, CCL3, and CCL17 increased dramatically, reaching significantly higher levels in patients with RA. Monocytes failed to express these CK, except for CXCL8 and CCL3. IC-mediated triggering of the Fc gamma R on DC from patients with highly active RA down regulated all CK, whereas the reverse was seen when DC from patients with low disease activity and healthy donors were stimulated. CCL18 was significantly increased in RA synovial tissue.

CONCLUSION

Increased CK expression by DC was found in patients with RA. This expression is partly regulated by Fc gamma R triggering and results in an inhibitory DC subtype in RA upon Fc gamma R-mediated triggering.

Gene therapy in animal models of rheumatoid arthritis: are we ready for the patients?

Rheumatoid arthritis (RA) is a chronic inflammatory disease of the synovial joints, with progressive destruction of cartilage and bone. Anti-tumour necrosis factor-α therapies (e.g. soluble tumour necrosis factor receptors) ameliorate disease in 60–70% of patients with RA. However, the need for repeated systemic administration of relatively high doses in order to achieve constant therapeutic levels in the joints, and the reported side effects are downsides to this systemic approach. Several gene therapeutic approaches have been developed to ameliorate disease in animal models of arthritis either by restoring the cytokine balance or by genetic synovectomy. In this review we summarize strategies to improve transduction of synovial cells, to achieve stable transgene expression using integrating viruses such as adeno-associated viruses, and to achieve transcriptionally regulated expression so that drug release can meet the variable demands imposed by the intermittent course of RA. Evidence from animal models convincingly supports the application of gene therapy in RA, and the feasibility of gene therapy was recently demonstrated in phase I clinical trials.

High production of proinflammatory and Th1 cytokines by dendritic cells from patients with rheumatoid arthritis, and down regulation upon FcgammaR triggering

OBJECTIVE

To assess whether DC from RA produce altered cytokine levels and whether this is regulated by triggering of Fc gamma receptors (FcgammaR).

METHODS

The production of proinflammatory (TNFalpha, IL1, IL6), Th1 (IL12, IFNgamma), and Th2 (IL10) cytokine profiles of immature DC (iDC) from patients with RA and healthy subjects upon triggering of FcgammaR dependent and independent pathways was investigated. iDC, derived from blood monocytes by standardised protocols, were stimulated with immune complexes (IC) at day 6 for 48 hours and, subsequently, for 2 days with LPS in the presence or absence of IC or IFNgamma, resulting in fully matured DC (mDC). IL1, IL6, TNFalpha, IFNgamma, IL12, and IL10 levels in supernatants were measured by ELISA and RIA.

RESULTS

mDC from patients with RA showed a markedly increased production of IL1, IL6, TNFalpha, and IL10 compared with DC from healthy donors. Triggering of FcgammaR decreased the production of proinflammatory cytokines IL1, IL12, and IFNgamma by iDC and mDC in RA and controls. The production of IL6 and TNFalpha decreased in patients with RA, whereas it was increased in controls. Triggering of FcgammaR independent mechanisms using IFNgamma increased the production of proinflammatory and Th1 cytokines, which was more pronounced in RA.

CONCLUSION

FcgammaR dependent pathways influence cytokine production by DC. A skewed balance towards proinflammatory and Th1 cytokines in RA can, at least partly, be restored by triggering FcgammaR on DC in RA. Insight into the mechanism which determines the FcgammaR balance might lead to new strategies to abrogate Th1 driven inflammatory processes in RA.