Inhibition of macropinocytosis blocks antigen presentation of type II collagen in vitro and in vivo in HLA-DR1 transgenic mice

Professional antigen-presenting cells, such as dendritic cells, macrophages and B cells have been implicated in the pathogenesis of rheumatoid arthritis, constituting a possible target for antigen-specific immunotherapy. We addressed the possibility of blocking antigen presentation of the type II collagen (CII)-derived immunodominant arthritogenic epitope CII(259–273 )to specific CD4 T cells by inhibition of antigen uptake in HLA-DR1-transgenic mice in vitro and in vivo. Electron microscopy, confocal microscopy, subcellular fractionation and antigen presentation assays were used to establish the mechanisms of uptake, intracellular localization and antigen presentation of CII by dendritic cells and macrophages. We show that CII accumulated in membrane fractions of intermediate density corresponding to late endosomes. Treatment of dendritic cells and macrophages with cytochalasin D or amiloride prevented the intracellular appearance of CII and blocked antigen presentation of CII(259–273 )to HLA-DR1-restricted T cell hybridomas. The data suggest that CII was taken up by dendritic cells and macrophages predominantly via macropinocytosis. Administration of amiloride in vivo prevented activation of CII-specific polyclonal T cells in the draining popliteal lymph nodes. This study suggests that selective targeting of CII internalization in professional antigen-presenting cells prevents activation of autoimmune T cells, constituting a novel therapeutic strategy for the immunotherapy of rheumatoid arthritis

Therapeutic Stimulation of Glycolytic ATP Production for Treating ROS-Mediated Cellular Senescence

Cellular senescence is conditioned through two interrelated processes, i.e., a reduction in adenosine triphosphate (ATP) and the enhancement of reactive oxygen species (ROS) production levels in mitochondria. ATP shortages primarily influence the energy-intensive synthesis of large biomolecules, such as deoxyribonucleic acid (DNA). In addition, as compared to small biomolecules, large biomolecules are more prone to ROS-mediated damaging effects. Based on the available evidence, we suggest that the stimulation of anaerobic glycolytic ROS-independent ATP production could restrain cellular senescence. Consistent with this notion, non-drug related intermittent hypoxia (IH)-based therapy could be effectively applied in sports medicine, as well as for supporting the physical activity of elderly patients and prophylactics of various age-related disorders. Moreover, drug therapy aiming to achieve the partial blockade of respiratory chain and downstream compensatory glycolysis enhancement could prove to be useful for treating cardiovascular, neurological and hormonal diseases. We maintain that non-drug/drug-related therapeutic interventions applied in combination over the entire lifespan could significantly rejuvenate and prolong a high quality of life for individuals

Immune-based, multifaceted inactivation of pathogenic T lymphocytes in treating autoimmune diseases

Immunotherapeutic treatment of autoimmune diseases should aim to inactivate autoaggressive memory T-cells and restore immune tolerance. It is envisaged that three approaches could be used to achieve this goal: stimulation of anti-idiotypic immune responses by vaccination with pathogenic T-cells; administration of suboptimal doses of antibodies (Abs) against two or more surface T-cell markers to provide selective Ab-mediated destruction of activated pathogenic memory T-cells; and induction of oral immune tolerance. The proposal entails the use of T-cell vaccination (TCV) or Ab-based therapy as an initial approach to reduce autoantigenic T-cell sensitization. Subsequently, the implementation of oral immunotherapy (OIT) is recommended to reinstate a consistent immune tolerance

Immunotherapy for treating metastatic colorectal cancer.

BACKGROUND Colorectal cancer remains one of the leading causes of death in the world. Surgery still remains the mainstay of treatment for primary and metastatic colorectal cancer. Immunotherapy used as an adjunct to surgery can play an important role in controlling the spread of tumour. METHODS The online databases PubMed, Medline, Scirus and Medscape Oncology were used to identify articles of relevance. Keywords included; "Immunotherapy", "Cellular Immunotherapy", "Metastatic Colorectal Cancer", "Monoclonal Antibody" "Tumour Vaccines" and "Adoptive Cell Therapy". The databases search was from the period of June 1995 until May 2010 inclusive. RESULTS Our understanding of tumour immunology has allowed the development of some successful therapies. Immunotherapy through the use of monoclonal antibodies is an effective adjunct to chemotherapy for metastatic colorectal cancer. Other modalities that are in the stages of development are cellular and conjugated vaccines. However, these vaccines are being experimented in advanced stages of colorectal tumours. CONCLUSION Colorectal cancer vaccines are being developed for advanced stages of colorectal tumour. However, their use as an early adjunct could potentially limit the spread of tumour or even result in cure. Further trials are required to ensure the safety and efficacy of cellular vaccines against colorectal tumours to allow their use on patients early in their disease presentation

Inflammation Control and Immunotherapeutic Strategies in Comprehensive Cancer Treatment

Tumor growth and expansion are determined by the immunological tumor microenvironment (TME). Typically, early tumorigenic stages are characterized by the immune system not responding or weakly responding to the tumor. However, subsequent tumorigenic stages witness the tumor promoting its growth and metastasis by stimulating tumor-protective (pro-tumor) inflammation to suppress anti-tumor immune responses. Here, we propose the pivotal role of inflammation control in a successful anti-cancer immunotherapy strategy, implying that available and novel immunotherapeutic modalities such as inflammation modulation, antibody (Ab)-based immunostimulation, drug-mediated immunomodulation, cancer vaccination as well as adoptive cell immunotherapy and donor leucocyte transfusion could be applied in cancer patients in a synergistic manner to amplify each other’s clinical effects and achieve robust anti-tumor immune reactivity. In addition, the anti-tumor effects of immunotherapy could be enhanced by thermal and/or oxygen therapy. Herein, combined immune-based therapy could prove to be beneficial for patients with advanced cancers, as aiming to provide long-term tumor cell/mass dormancy by restraining compensatory proliferation of surviving cancer cells observed after traditional anti-cancer interventions such as surgery, radiotherapy, and metronomic (low-dose) chemotherapy. We propose the Inflammatory Prognostic Score based on the blood levels of C-reactive protein and lactate dehydrogenase as well as the neutrophil-to-lymphocyte ratio to effectively monitor the effectiveness of comprehensive anti-cancer treatment

Profound invariant natural killer T-cell deficiency in inflammatory arthritis

Objectives: Data from rodent models indicate that invariant natural killer T (iNKT) cells are key regulators of many immune responses including autoimmune arthritis, but their role in human diseases is unclear. The aims of this study are to determine whether iNKT cell frequency and function are altered in patients with rheumatoid arthritis (RA), and the clinical significance of such iNKT cell abnormalities. Methods: Peripheral blood iNKT cell frequency and proliferative response to an iNKT cell-specific agonist, a-galactosylceramide were measured in 46 RA patients (including 23 untreated, newly diagnosed patients), 22 healthy controls and 27 patients presenting with recent-onset joint pain. The relationship between iNKT cell frequency and clinical characteristics and the effects of immunosuppressive treatment was examined. Results: Compared with healthy controls, RA patients had a decreased frequency of peripheral blood iNKT cells (median 0.001% vs 0.021%, p < 0.001) and the proliferative response of this subset to a-galactosylceramide was also diminished in the patient group (median fold-expansion 31 vs 121, p = 0.037). These abnormalities preceded the initiation of disease-modifying or immunosuppressive therapy, whose effect was to increase the circulating iNKT cell frequency (p = 0.037). Furthermore, iNKT cell frequency correlated inversely with the systemic inflammatory marker, C-reactive protein (p = 0.008). Finally, in patients presenting with recent-onset joint symptoms, normal peripheral blood iNKT cell frequency predicted a non-inflammatory cause of joint pain. Conclusion: iNKT cell deficiency is present in patients with RA and other inflammatory arthropathy. Normal iNKT cell frequency predicts non-inflammatory causes of joint pain

T cell responses to a non‐glycosylated epitope predominate in type II collagen‐immunised HLA‐DRB1*0101 transgenic mice

Aim: To study collagen-induced arthritis in human leucocyte antigen (HLA)-DR1 transgenic mice lacking endogenous major histocompatibility complex class II molecules (MHC-II) and to determine T cell specificity against the arthritogenic CII259-273 epitope of type II collagen either unmodified or post-translationally glycosylated at Lys(264). Methods: Arthritis was induced by immunisation with human type II collagen in complete Freund's adjuvant and measured by footpad swelling, clinical score and histology. T cell responses were assessed by proliferation of spleen and lymph node cells and in antigen presentation assays, using T cell hybridomas specific for the glycosylated and non-glycosylated CII259-273 epitope. Results: The incidence of arthritis was 50% in DR1-transgenic mice lacking endogenous MHC-II molecules. Recall T cell responses in draining lymph nodes and spleen were consistently greater against the nonglycosylated epitope than to the glycosylated CII259-273. Most of the T cell hybridomas generated from CII-immunised mice recognised the non-glycosylated CII epitope and this form of the epitope was also presented with 100-fold higher efficiency and 1 h faster kinetics by both macrophages and dendritic cells. Conclusion: This study shows that T cell responses to the non-glycosylated epitope of heterologous ( human) CII are dominant in HLA-DR1 transgenic mice lacking MHC-II, which could contribute to the pathogenicity of autoimmune arthritis

Impaired TH17 responses in patients with chronic mucocutaneous candidiasis with and without autoimmune polyendocrinopathy-candidiasis- ectodermal dystrophy

Background Accumulating evidence implicates TH17 cytokines in protection against Candida species infections, but the clinical relevance is not clear. Chronic mucocutaneous candidiasis (CMC) is a heterogeneous syndrome with the unifying feature of selective susceptibility to chronic candidiasis. Different subgroups with distinct clinical features are recognized, including autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED), CMC with hypothyroidism, and isolated CMC. Understanding immune defects in patients with CMC will define cellular and molecular mechanisms crucial for protection against Candida species in human subjects. Objectives We sought to determine whether impaired TH17 responses underlie susceptibility to Candida species infections and whether the same defect is present in different CMC subgroups. Methods We assessed TH17 responses of PBMCs to Candida and non-Candida species stimuli by measuring IL-17, IL-22, IL-21, IL-6, IL-23, and IFN-γ cytokine production using cytokine arrays and intracellular cytokine-producing cell numbers and proliferation with flow cytometry. PBMCs from healthy subjects and unaffected family members served as controls. Results In patients with CMC with hypothyroidism, TH17 cells demonstrated decreased proliferation and IL-17 production in response to Candida species. In contrast, in patients with APECED, TH17 cell proliferation and IL-17 production were normal unless exposed to APECED plasma, which inhibited both functions in both APECED and normal PBMCs. Candida species–stimulated IL-22 production was impaired in all patients with CMC, whereas IL-6 and IL-23 responses were unaltered. Conclusion An impaired TH17 response to Candida species, although mediated by different mechanisms, was present in all CMC subgroups studied and might be a common factor predisposing to chronic candidiasis