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An intrinsic B-cell defect supports autoimmunity in New Zealand black chromosome 13 congenic mice.

Introgression of a New Zealand Black (NZB) chromosome 13 interval onto a C57BL/6 (B6) background (B6.NZBc13) is sufficient to produce many hallmarks of lupus, including high-titre anti-chromatin antibody production, abnormal B- and T-cell activation, and renal disease. In this study we sought to characterize the immune defects leading to these abnormalities. By generating hematopoietic chimeras and BCR transgenic mice, we show that the congenic autoimmune phenotype can be transferred by BM cells and requires the presence of autoreactive B cells. Using the hen egg white lysozyme immunoglobulin

Germinal centers regulate human Th2 development.

In the present study we demonstrate that all CD4(+) T cells in human tonsil expressing the Th2-selective receptor chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) also 1) express high levels of CXCR5, and 2) display a transitional CD45RA/RO phenotype and consistently do not produce significant amounts of cytokines when immediately analyzed ex vivo. Hence, they represent precursors of Th2 effector cells, a conclusion confirmed by their robust production of IL-4, IL-5, and IL-13, but not IFN-gamma, after in vitro activation. CD4(+) T cells, which express only intermedi

Thymus and autoimmunity: production of CD25+CD4+ naturally anergic and suppressive T cells as a key function of the thymus in maintaining immunologic self-tolerance.

This study shows that the normal thymus produces immunoregulatory CD25+4+8- thymocytes capable of controlling self-reactive T cells. Transfer of thymocyte suspensions depleted of CD25+4+8- thymocytes, which constitute approximately 5% of steroid-resistant mature CD4+8- thymocytes in normal naive mice, produces various autoimmune diseases in syngeneic athymic nude mice. These CD25+4+8- thymocytes are nonproliferative (anergic) to TCR stimulation in vitro, but potently suppress the proliferation of other CD4+8- or CD4-8+ thymocytes; breakage of their anergic state in vitro by high doses of IL-2

Frequency and functional characterization of exhausted CD8+ T cells in chronic lymphocytic leukemia.

OBJECTIVES: The phenotypic and functional properties of Tim-3+ /PD-1+ /CD8+ cells as exhausted T cells were investigated in chronic lymphocytic leukemia (CLL). METHODS: Frequency of CD8+ /Tim-3+ /PD-1+ exhausted cells was determined by flow cytometry. For functional analysis, magnetic beads-isolated CD8+ T cells were stimulated with PHA and PMA/ionocymin to assess their proliferative responses and cytokine production by MTT and ELISA, respectively. Cytotoxic activity of isolated CD8+ T cells was determined using CD107a degranulation assay. RESULTS: The proportion of exhausted CD8+ T cells wa

Complement receptor 2/CD21- human naive B cells contain mostly autoreactive unresponsive clones.

Complement receptor 2-negative (CR2/CD21(-)) B cells have been found enriched in patients with autoimmune diseases and in common variable immunodeficiency (CVID) patients who are prone to autoimmunity. However, the physiology of CD21(-/lo) B cells remains poorly characterized. We found that some rheumatoid arthritis (RA) patients also display an increased frequency of CD21(-/lo) B cells in their blood. A majority of CD21(-/lo) B cells from RA and CVID patients expressed germline autoreactive antibodies, which recognized nuclear and cytoplasmic structures. In addition, these B cells were unable

Lymph node cells from BALB/c mice with chronic visceral leishmaniasis exhibiting cellular anergy and apoptosis: involvement of Ser/Thr phosphatase.

Visceral leishmaniasis (VL) produced in BALB/c mice through intracardial administration of Leishmania donovani amastigotes was accompanied by hepatosplenomegaly with high organ parasite load and lymphadenopathy when followed up to 4-months or so. To elucidate the mechanism of immunosuppression associated with VL, we report here progressive impairment of the proliferative response of lymph node cells (lymphocytes) from infected animals (I-LNC) to in vitro stimulation with the combination of phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io) that could be related to the downregulation of P

Human anergic/suppressive CD4(+)CD25(+) T cells: a highly differentiated and apoptosis-prone population.

Anergic/suppressive CD4(+)CD25(+) T cells exist in animal models but their presence has not yet been demonstrated in humans. We have identified and characterized a human CD4(+)CD25(+) T cell subset, which constitutes 7-10 % of CD4(+) T cells in peripheral blood and tonsil. These cells are a CD45RO(+)CD45RB(low) highly differentiated primed T cell population that is anergic to stimulation. Depletion of this small subset from CD4(+) T cells significantly enhances proliferation by threefold in the remaining CD4(+)CD25(-) T cells, while the addition of isolated CD4(+)CD25(+) T cells to CD4(+)CD25(

Ablation of CD8 and CD4 T cell responses by high viral loads.

To evaluate the impact of sustained viral loads on anti-viral T cell responses we compared responses that cleared acute lymphocytic choriomeningitis virus infection with those that were elicited but could not resolve chronic infection. During acute infection, as replicating virus was cleared, CD8 T cell responses were down-regulated, and a pool of resting memory cells developed. In chronically infected hosts, the failure to control the infection was associated with pronounced and prolonged activation of virus-specific CD8 T cells. Nevertheless, there was a progressive diminution of their effec

CTLA-4 blockade reverses CD8+ T cell tolerance to tumor by a CD4+ T cell- and IL-2-dependent mechanism.

A tumor-specific CD8+ T cell response was studied using adoptive transfer of OT-I TCR transgenic cells. Upon i.p. challenge with E.G7 tumor, OT-I cells undergo CD4+ T cell-independent expansion at the tumor site and develop lytic function. Before tumor elimination, however, they leave the peritoneal cavity (PC) and appear in the LN and spleen where they exhibit "split anergy" and cannot further proliferate to antigen. Administering anti-CTLA-4 mAb early caused sustained OT-1 expansion in the PC, and late administration caused the OT-I cells to return to the PC and further expand; in both cases

Human CD25+ regulatory T cells maintain immune tolerance to nickel in healthy, nonallergic individuals.

We investigated the capacity of CD25(+) T regulatory cells (Treg) to modulate T cell responses to nickel, a common cause of allergic contact dermatitis. CD4(+) T cells isolated from the peripheral blood of six healthy, nonallergic individuals showed a limited capacity to proliferate in response to nickel in vitro, but responsiveness was strongly augmented (mean increment +/- SD, 240 +/- 60%) when cells were depleted of CD25(+) Treg. Although CD25(+) Treg were anergic to nickel, a small percentage up-regulated membrane CTLA-4 upon nickel exposure. CD25(+) Treg strongly and dose-dependently inhi

Hematopoietic chimerism and transplantation tolerance: a role for regulatory T cells.

The immunosuppressive regimens currently used in transplantation to prevent allograft destruction by the host's immune system have deleterious side effects and fail to control chronic rejection processes. Induction of donor-specific non-responsiveness (i.e., immunological tolerance) to transplants would solve these problems and would substantially ameliorate patients' quality of life. It has been proposed that bone marrow or hematopoietic stem-cell transplantation, and resulting (mixed) hematopoietic chimerism, lead to immunological tolerance to organs of the same donor. However, a careful ana

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… Finally, hematopoietic cells can also cause T cell tolerance by inducing a non-responsive state called clonal anergy (Rammensee et al., 1989 ; Tomita et al., 1994 ; Hawiger et al., 2001 ). … Evidence for involvement of clonal anergy in MHC class I and class II disparate skin allograft tolerance after the termination of intrathymic clonal deletion . J. Immunol. 145 , 4026 – 4036 2147933 Trentin J. J. ( 1956 ). …

T cell hyporesponsiveness induced by oral administration of ovalbumin is associated with impaired NFAT nuclear translocation and p27kip1 degradation.

Oral tolerance is an important physiological component of the immune system whereby the organism avoids dangerous reactions such as hypersensitivity to ingested food proteins and other luminal Ags which may cause tissue damage and inflammation. In addition, it has been shown in animal models and in humans that oral tolerance can be applied to controlling undesired immune responses, including autoimmune diseases, allergies, and organ transplant rejections. However, the molecular mechanisms of oral tolerance have been poorly defined. In this study, we investigated the molecular basis underlying

The trinity of T cell engagement: navigating the molecular and clinical landscape of CAR-T, TILs, and TCEs in the war against cancer.

The advent of cancer immunotherapy has fundamentally restructured the oncological paradigm, moving away from agents that directly target tumor cell kinetics toward strategies that empower the host immune system to recognize and eliminate malignancy. Central to this revolution is the cytotoxic T lymphocyte (CTL), now harnessed as a potent "living drug" through engineered and naturally selected modalities. This review provides a critical, in-depth examination of the three dominant pillars of T cell-driven therapies: Chimeric Antigen Receptor T-cell (CAR-T) therapy, Tumor-Infiltrating Lymphocyte

Pathogenesis and treatment of Sjogren's syndrome: Review and update.

Sjogren's syndrome (SS) is a chronic autoimmune disease accompanied by multiple lesions. The main manifestations include dryness of the mouth and eyes, along with systemic complications (e.g., pulmonary disease, kidney injury, and lymphoma). In this review, we highlight that IFNs, Th17 cell-related cytokines (IL-17 and IL-23), and B cell-related cytokines (TNF and BAFF) are crucial for the pathogenesis of SS. We also summarize the advances in experimental treatment strategies, including targeting Treg/Th17, mesenchymal stem cell treatment, targeting BAFF, inhibiting JAK pathway, et al. Similar

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… Inhibition of cell cycle progression by rapamycin induces T cell clonal anergy even in the presence of costimulation. J Immunol (1999) 162(5):2775–84. doi: 10.4049/jimmunol.162.5.2775 102. Powell JD, Pollizzi KN, Heikamp EB, Horton MR. Regulation of immune responses by mTOR. …

Revitalizing T cells: breakthroughs and challenges in overcoming T cell exhaustion.

T cell exhaustion is a prevalent phenomenon in chronic infections and tumor microenvironments, severely compromising the effectiveness of antitumor and antiviral immunity. In recent years, there has been significant progress in understanding the underlying mechanisms of T cell exhaustion, including external factors and intrinsic cellular changes that drive this dysfunctional state. Key external factors such as persistent antigen exposure, immune checkpoint signaling, and the cytokine milieu, as well as intrinsic changes such as altered metabolic processes, epigenetic modifications, and transcr

Myeloid-Derived Suppressor Cells and Mesenchymal Stem/Stromal Cells in Myeloid Malignancies.

Myeloid malignancies arise from an altered hematopoietic stem cell and mainly comprise acute myeloid leukemia, myelodysplastic syndromes, myeloproliferative malignancies, and chronic myelomonocytic leukemia. Myeloid neoplastic leukemic cells may influence the growth and differentiation of other hematopoietic cell lineages in peripheral blood and bone marrow. Myeloid-derived suppressor cells (MDSCs) and mesenchymal stromal cells (MSCs) display immunoregulatory properties by controlling the innate and adaptive immune systems that may induce a tolerant and supportive microenvironment for neoplasm

Reversing Autoimmunity Combination of Rituximab and Intravenous Immunoglobulin.

In this concept paper, the authors present a unique and novel protocol to treat autoimmune diseases that may have the potential to reverse autoimmunity. It uses a combination of B cell depletion therapy (BDT), specifically rituximab (RTX) and intravenous immunoglobulin (IVIg), based on a specifically designed protocol (Ahmed Protocol). Twelve infusions of RTX are given in 6-14 months. Once the CD20+ B cells are depleted from the peripheral blood, IVIg is given monthly until B cells repopulation occurs. Six additional cycles are given to end the protocol. During the stages of B cell depletion,

The Use of Immune Checkpoint Inhibitors in Oncology and the Occurrence of AKI: Where Do We Stand?

Immune checkpoint inhibitors (ICIs) are a novel class of immunotherapy drugs that have improved the treatment of a broad spectrum of cancers as metastatic melanoma, non-small lung cancer or renal cell carcinoma. These humanized monoclonal antibodies target inhibitory receptors (e.g. CTLA-4, PD-1, LAG-3, TIM-3) and ligands (PD-L1) expressed on T lymphocytes, antigen presenting cells and tumor cells and elicit an anti-tumor response by stimulating immune system. Nevertheless, the improved overall survival is complicated by the manifestation of Immune-related Adverse Effects (irAEs). During treat

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… Antagonistic roles for CTLA-4 and the mammalian target of rapamycin in the regulation of clonal anergy: enhanced cell cycle progression promotes recall antigen responsiveness. J Immunol (2001) 167:5636–44. 10.4049/jimmunol.167.10.5636 108. …

Advances and Hurdles in CAR T Cell Immune Therapy for Solid Tumors.

Chimeric antigen receptor (CAR) T cells in solid tumors have so far yielded limited results, in terms of therapeutic effects, as compared to the dramatic results observed for hematological malignancies. Many factors involve both the tumor cells and the microenvironment. The lack of specific target antigens and severe, potentially fatal, toxicities caused by on-target off-tumor toxicities constitute major hurdles. Furthermore, the tumor microenvironment is usually characterized by chronic inflammation, the presence of immunosuppressive molecules, and immune cells that can reduce CAR T cell effi

Renal Involvement in Mixed Cryoglobulinemic Vasculitis: Current Perspectives.

Cryoglobulinemia is a rare disorder characterized by the presence of abnormal proteins (cryoglobulins) in the blood that precipitate at low temperatures. It presents with a wide clinical spectrum, from mild symptoms to severe, life-threatening disease. In mixed cryoglobulinemia (MC), vascular damage results from immune complexes-typically monoclonal IgM with rheumatoid factor activity and polyclonal IgG (Type II), or polyclonal/oligoclonal IgM and IgG (Type III). These complexes can obstruct small blood vessels, leading to ischemia and leukocytoclastic vasculitis. Renal involvement occurs in a