The suppressive effect of TGF-beta on IL-12-mediated immune modulation specific to a peptide Ac1-11 of myelin basic protein (MBP): a mechanism involved in inhibition of both IL-12 receptor beta1 and beta2

Dual Biologic Therapy in an Adolescent With Camurati-Engelmann Disease and Crohn Disease

Camurati-Engelmann disease (CED) is a rare disorder caused by activating mutations in the TGF-β1 gene and characterized by hyperostosis of long bones and bone dysplasia. We describe a case of an adolescent with CED and moderate-severe Crohn Disease (CD). Infliximab improved gastrointestinal symptoms but was associated with worsening CED-associated bone pain. Clinical remission was successfully achieved with dual biologic therapy that included vedolizumab and ustekinumab. Possible reasons for this patient's clinical response are advanced and include speculation about the complex role of TGF-β1 signaling in the etiology of both CED and CD.

NHS-IL12 and bintrafusp alfa combination therapy enhances antitumor activity in preclinical cancer models

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Combination therapy induced both adaptive and innate antitumor immunity.

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Combination therapy significantly enhanced antitumor activity.

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Combination therapy generated tumor antigen specific immune memory.

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Bintrafusp alfa mediated the reduction of lung metastases.

Combinatorial immunotherapy approaches are emerging as viable cancer therapeutic strategies for improving patient responses and outcomes. This study investigated whether two such immunotherapies, with complementary mechanisms of action, could enhance antitumor activity in murine tumor models. The immunocytokine NHS-IL12, and surrogate NHS-muIL12, are designed to deliver IL-12 and muIL-12, respectively, to the tumor microenvironment (TME) to activate NK cells and CD8⁺ T cells and increase their cytotoxic functions. Bintrafusp alfa (BA) is a bifunctional fusion protein composed of the extracellular domains of the TGF-β receptor II to function as a TGF-β “trap” fused to a human IgG1 antibody blocking PD-L1. With this dual-targeting strategy, BA enhances efficacy over that of monotherapies in preclinical studies. In this study, NHS-muIL12 and BA combination therapy enhanced antitumor activity, prolonged survival, and induced tumor-specific antitumor immunity. This combination therapy increased tumor-specific CD8⁺ T cells and induced immune profiles, consistent with the activation of both adaptive and innate immune systems. In addition, BA reduced lung metastasis in the 4T1 model. Collectively, these findings could support clinical trials designed to investigate NHS-IL12 and BA combination therapy for patients with advanced solid tumors

Autocrine TGF-β1 Maintains the Stability of Foxp3+ Regulatory T Cells via IL-12Rβ2 Downregulation

Transforming growth factor beta 1 (TGF-β1) is an immunosuppresive cytokine that plays an essential role in immune homeostasis. It is well known that regulatory T (Treg) cells express TGF-β1; however, the role of autocrine TGF-β1 in the development, function, and stability of Treg cells remains poorly understood. We found that Treg cell-derived TGF-β1 was not required for the development of thymic Treg cells in mice, but played a role in the expression of latency-associated peptide and optimal suppression of naïve T cell proliferation in vitro. Moreover, the frequency of Treg cells was significantly reduced in the mesenteric lymph nodes of the Treg cell-specific TGF-β1-deficient mice, which was associated with increased frequency of IFN-γ-producers among Treg cells. TGF-β1-deficient Treg cells were more prone to express IFN-γ than TGF-β1-sufficient Treg cells in a dendritic cell-mediated stimulation in vitro as well as in an adoptive transfer study in vivo. Mechanistically, TGF-β1-deficient Treg cells expressed higher levels of Il12rb2 and were more sensitive to IL-12-induced conversion into IFN-γ-producing Treg cells or IFN-γ-producing exTreg cells than TGF-β1-sufficient Treg cells. Our findings demonstrate that autocrine TGF-β1 plays a critical role in the optimal suppressive activity and stability of Treg cells by downregulating IL-12R on Treg cells.

Anti-MS4a4B treatment abrogates MS4a4B-mediated protection in T cells and ameliorates experimental autoimmune encephalomyelitis

Recent data show that anti-CD20 therapy is effective for some autoimmune diseases, including multiple sclerosis (MS). However, the efficacy of anti-CD20 therapy for MS is largely limited because anti-CD20 antibodies target only B cells. In previous studies, we have investigated the function of MS4a4B, a novel CD20 homologue, in T cell proliferation. Here, we found that MS4a4B regulates not only T cell proliferation but also T cell apoptosis. Knockdown of MS4a4B by MS4a4B-siRNA or MS4a4B-shRNA-expressing vector promoted apoptosis in primary T cells and T32 cell line. In contrast, vector-driven over-expression of MS4a4B reduced apoptosis in EL-4 cells. Machinery analysis showed that MS4a4B-mediated T cell survival was associated with decreased activity of caspases 3, 8 and 9. Interestingly, binding of anti-MS4a4B antibodies to T cells induced activated T cells to undergo apoptosis. To test whether anti-MS4a4B antibody interferes with MS4a4B-mediated protection of T cells, we injected anti-MS4a4B antibodies into mice with experimental autoimmune encephalomyelitis (EAE). The results show that anti-MS4a4B treatment ameliorated the severity of EAE, accompanied by decreased Th1 and Th17 cell responses and reduced levels of pro-inflammatory cytokines in the central nervous system, suggesting that MS4a4B may serve as a target of antibody-based therapy for T cell-mediated diseases.

T-regulatory lymphocytes and chronic viral hepatitis

Both hepatitis B virus (HBV) and hepatitis C virus (HCV) can cause persistent viral infection in humans. Chronic infection is associated with a risk of cirrhosis and hepatocellular carcinoma. The cause of chronic infection is unknown. A large body of evidence suggests that a failure of the adaptive immune response is critical in the establishment of chronic infection. Recently a new group of T cells (T-regulatory cells), that express CD4(+)CD25(+) and Foxp3, which can inhibit the cellular (CD4(+)/CD8(+)) immune response have been described. In this review the authors explore the thoughts regarding immune responses to HBV and HCV infections and the role of these T-regulatory cells in relation to the pathogenesis of chronic HBV and HCV infection and the potential for therapeutic intervention.

Transforming growth factor-beta controls T helper type 1 cell development through regulation of natural killer cell interferon-gamma

Interferon-gamma and interleukin 12 produced by the innate arm of the immune system are important regulators of T helper type 1 (T(H)1) cell development, but signals that negatively regulate their expression remain controversial. Here we show that transforming growth factor-beta (TGF-beta) controlled T(H)1 differentiation through the regulation of interferon-gamma produced by natural killer (NK) cells. Blockade of TGF-beta signaling in NK cells caused the accumulation of a large pool of NK cells secreting copious interferon-gamma, responsible for T(H)1 differentiation and protection from leishmania infection. In contrast, blockade of TGF-beta signaling in dendritic cells did not affect dendritic cell homeostasis or interleukin 12 production, thus indicating a previously undescribed demarcation of the function of TGF-beta in NK cells versus dendritic cells.

Role of IL-12 receptor beta 1 in regulation of T cell response by APC in experimental autoimmune encephalomyelitis

IL-12 was thought to be involved in the development of experimental autoimmune encephalomyelitis (EAE), a Th1 cell-mediated autoimmune disorder of the CNS. However, we have recently found that IL-12 responsiveness, via IL-12Rbeta2, is not required in the induction of EAE. To determine the role of IL-12Rbeta1, a key subunit for the responsiveness to both IL-12 and IL-23, in the development of autoimmune diseases, we studied EAE in mice deficient in this subunit of IL-12R. IL-12Rbeta1(-/-) mice are completely resistant to myelin oligodendrocyte glycoprotein (MOG)-induced EAE, with an autoantigen-specific Th2 response. To study the mechanism underlying this Th2 bias, we cocultured purified CD4(+) T cells and APCs of MOG-immunized mice. We demonstrate that IL-12Rbeta1(-/-) APCs drive CD4(+) T cells of both wild-type and IL-12Rbeta1(-/-) mice to an Ag-induced Th2 phenotype, whereas wild-type APCs drive these CD4(+) T cells toward a Th1 type. IL-12Rbeta1(-/-) CD4(+) T cells, in turn, appear to exert an immunoregulatory effect on the capacity of wild-type APCs to produce IFN-gamma and TNF-alpha. Furthermore, decreased levels of IL-12p40, p35, and IL-23p19 mRNA expression were found in IL-12Rbeta1(-/-) APCs, indicating an autocrine pathway of IL-12/IL-23 via IL-12Rbeta1. IL-18 production and IL-18Ralpha expression are also significantly decreased in IL-12Rbeta1(-/-) mice immunized with MOG. We conclude that in the absence of IL-12Rbeta1, APCs play a prominent regulatory role in the induction of autoantigen-specific Th2 cells.

Identification of Necrosis-Associated Genes in Glioblastoma by cDNA Microarray Analysis

PURPOSE

In the field of cancer research, there has been a paucity of interest in necrosis, whereas studies focusing on apoptosis abound. In neuro-oncology, this is particularly surprising because of the importance of necrosis as a hallmark of glioblastoma (GBM), the most malignant and most common primary brain tumor, and the fact that the degree of necrosis has been shown to be inversely related to patient survival. It is therefore of considerable interest and importance to identify genes and gene products related to necrosis formation.

EXPERIMENTAL DESIGN

We used a nylon cDNA microarray to analyze mRNA expression of 588 universal cellular genes in 15 surgically resected human GBM samples with varying degrees of necrosis. Gene expression was correlated with the degree of necrosis using rank correlation coefficients. The expression of identified genes was compared with their expression in tissue samples from 5 anaplastic astrocytomas (AAs). Immunostaining was used to determine whether genes showing the most positive correlation with necrosis were increasingly expressed in tumor tissues, as grade of necrosis increased.

RESULTS

The hybridization results indicated that 26 genes showed significant correlation with the amount of necrosis. All 26 genes had functions associated with either Ras, Akt, tumor necrosis factor alpha, nuclear factor kappaB, apoptosis, procoagulation, or hypoxia. Nine genes were positively correlated with necrosis grade, and 17 genes were negatively correlated with necrosis grade. There were significant differences in the median expression levels of 3 of the 26 genes between grade III necrosis GBM and anaplastic astrocytoma (AA) samples; all but 1 of the genes had elevated expression when comparing necrosis grade III with AA samples. Two factors, the ephrin type A receptor 1 and the prostaglandin E(2) receptor EP4 subtype, not previously considered in this context, were highlighted because of their particularly high (positive) correlation coefficients; immunostaining showed the products of these two genes to be localized in perinecrotic and necrotic regions and to be overexpressed in grade III GBMs, but not AAs. These two molecules also showed significant correlation with survival of GBM patients (P = 0.0034) in a combined model.

CONCLUSIONS

The application of cDNA expression microarray analysis has identified specific genes and patterns of gene expression that may help elucidate the molecular basis of necrogenesis in GBM. Additional studies will be required to further investigate and confirm these findings.

Differential expression and regulation of IL-23 and IL-12 subunits and receptors in adult mouse microglia

IL-23 and IL-12 are functionally related heterodimeric cytokines that share the IL-12p40 subunit. IL-23 and IL-12 function through heterodimeric receptors, which share the IL-12Rbeta1 subunit. Production of IL-23, a heterodimer of IL-12p40 and IL-23p19, by CNS antigen-presenting cells (APC) is critical for susceptibility to experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis (MS). We report that the expression of IL-23p19 mRNA is highly induced by stimulation with IFN-gamma and LPS in adult mouse microglia and a microglia cell line, EOC13. Expression of the IL-12R subunits, IL-12Rbeta1 and IL-12Rbeta2, is upregulated in both microglia and splenic macrophages upon stimulation with LPS or IFN-gamma and LPS, whereas the IL-23R subunit is upregulated only in macrophages. In EAE, an early peak of IL-23p19 mRNA expression is found in CD11b(+) CNS APC, compared with peripheral macrophages. In contrast, IL-12p40 and IL-12p35 mRNA maximum levels in the CNS are detected at peak of disease. The expression of IL-12p35 mRNA is more sustained than that of IL-12p40 and IL-23p19. Thus, IL-23 produced by CNS microglia/macrophages may contribute to the early induction of EAE. In the CNS, IL-23 may preferentially target infiltrating mononuclear cells, which upregulate IL-23R, rather than parenchymal microglia.

Pathogenesis of autoimmunity after xenogeneic thymus transplantation

Thymus transplantation is a promising strategy to induce xenotolerance, but may also induce an autoimmune syndrome (AIS). The pathogenesis of this AIS was explored using nude rats as recipients. Thymus grafts consisted of fetal hamster thymic tissue with or without mixing with fetal rat tissue such as thymus, thyroid, salivary gland, and heart. All hamster thymus recipients died of AIS within 2-3 mo. In most recipients of xenothymus mixed with rat tissues such as thymus, thyroid, and salivary gland, but not heart, AIS was prevented, indicating an insufficient presence of rat epithelial cell Ags within the xenothymus. AIS could be transferred to control nude rats by whole splenocytes or by splenocyte subpopulations such as CD3(+), CD3(-), and B lymphocytes, but not by non-T, non-B cells from AIS animals. This transfer could be suppressed by cotransferring either CD4(+) or CD8(+) lymphocytes from euthymic rats, but not by splenocytes from recipients of syngeneic or xenogeneic thymus mixed with rat tissue, indicating a defective generation of regulatory lymphocytes. As for CD4(+) regulatory cells this defect was probably qualitative, because the percentages of CD4(+)CD25(+) or CD4(+)CD45RC(low) populations were normal after xenothymus transplantation. As for the CD8(+) regulatory cells, the defect was quantitative, as CD8(+) cell levels always remained low. The latter was related to the nonvascularized nature of thymus grafts. In conclusion, AIS after xenothymus transplantation in nude rats is due to a combination of insufficient intrathymic presence of host-type epithelial cell Ags and a defective generation of regulatory T lymphocytes.

IL-12p35-deficient mice are susceptible to experimental autoimmune encephalomyelitis: evidence for redundancy in the IL-12 system in the induction of central nervous system autoimmune demyelination

Experimental autoimmune encephalomyelitis (EAE) serves as a model for multiple sclerosis and is considered a CD4(+), Th1 cell-mediated autoimmune disease. IL-12 is a heterodimeric cytokine, composed of a p40 and a p35 subunit, which is thought to play an important role in the development of Th1 cells and can exacerbate EAE. We induced EAE with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 (MOG(35-55)) in C57BL/6 mice and found that while IL-12p40-deficient (-/-) mice are resistant to EAE, IL-12p35(-/-) mice are susceptible. Typical spinal cord mononuclear cell infiltration and demyelination were observed in wild-type and IL-12p35(-/-) mice, whereas IL-12p40(-/-) mice had normal spinal cords. A Th1-type response to MOG(35-55) was observed in the draining lymph node and the spleen of wild-type mice. A weaker MOG(35-55)-specific Th1 response was observed in IL-12p35(-/-) mice, with lower production of IFN-gamma. By contrast, a Th2-type response to MOG(35-55) correlated with disease resistance in IL-12p40(-/-) mice. Production of TNF-alpha by microglia, CNS-infiltrating macrophages, and CD4(+) T cells was detected in wild-type and IL-12p35(-/-), but not in IL-12p40(-/-), mice. In addition, NO production was higher in IL-12p35(-/-) and wild-type mice than in IL-12p40(-/-) mice. These data demonstrate a redundancy of the IL-12 system in the induction of EAE and suggest that p40-related heterodimers, such as the recently cloned IL-23 (p40p19), may play an important role in disease pathogenesis.

Mature bone marrow-derived dendritic cells polarize Th2 response and suppress experimental autoimmune encephalomyelitis

Distinct subsets of dendritic cells (DCs) based on the origin, phenotypes, and the nature of the signals that promote DC maturation can determine polarized immune responses of T cells. In this study, DCs were cultured from mouse bone marrow (BM) progenitors in granulocyte-macrophage colony-stimulating factor (GM-CSF). To generate mature DCs (mDCs), lipopolysaccharide (LPS) was used in the culture for 24 h. LPS-stimulated DCs were phenotypically mature, which exhibited strongly upregulated CD40, B7.1, and B7.2 compared to non-LPS-stimulated immature DCs (imDCs). Both mDCs and imDCs expressed high levels of MHC class II but low level of CD54. mDCs produced higher levels of IL-10 and lower IL-12 compared to imDCs. No IFN-gamma or IL-4 was found in both groups. When mDCs were injected intraperitoneally (i.p.) to the mice with experimental autoimmune encephalomyelitis (EAE), the severity of clinical signs and inflammation in the CNS was significantly suppressed compared to imDC-injected mice (p<0.01) and PBS-injected mice (p<0.02). Moreover, lymphocytes from mDC-injected mice produced lower level of IL-12, IFN-gamma, but higher level of IL-10, compared to imDC-injected and non-DC-injected mice. We conclude that BM-mDCs, but not BM-imDCs, promote Th2 differentiation and have the potential for suppression of inflammatory demyelination.

The immunology of mucosal models of inflammation

In recent years the status of the inflammatory bowel diseases (IBDs) as canonical autoimmune diseases has risen steadily with the recognition that these diseases are, at their crux, abnormalities in mucosal responses to normally harmless antigens in the mucosal microflora and therefore responses to antigens that by their proximity and persistence are equivalent to self-antigens. This new paradigm is in no small measure traceable to the advent of multiple models of mucosal inflammation whose very existence is indicative of the fact that many types of immune imbalance can lead to loss of tolerance for mucosal antigens and thus inflammation centered in the gastrointestinal tract. We analyze the immunology of the IBDs through the lens of the murine models, first by drawing attention to their common features and then by considering individual models at a level of detail necessary to reveal their individual capacities to provide insight into IBD pathogenesis. What emerges is that murine models of mucosal inflammation have given us a road map that allows us to begin to define the immunology of the IBDs in all its complexity and to find unexpected ways to treat these diseases.

The role of IL-12 in the induction of intravenous tolerance in experimental autoimmune encephalomyelitis

Intravenous administration of autoantigen is an effective method to induce Ag-specific tolerance against experimental autoimmune encephalomyelitis (EAE). IL-12 is a potent Th1 stimulator and an essential cytokine in the induction of EAE. The role of IL-12 in the induction of i.v. tolerance is not clear. In this study, we induced tolerance by i.v. administering myelin basic protein (MBP) peptide Ac1-11 (MBP1-11) in EAE. We observed significant suppression of IL-12 production by the lymph node cells of MBP1-11-injected mice. To see whether the low level of IL-12 is the cause or effect of tolerance, we administered IL-12 to the EAE mice at the time of i.v. MBP1-11 injection. Exogenous IL-12 abrogated the suppression of clinical and pathological EAE by i.v. tolerance. IL-12 blocked the suppressive effect of i.v. tolerance on the proliferative response to MBP1-11 and MBP1-11-induced production of IL-12 and IFN-gamma. Furthermore, IL-12 completely blocked the i.v. tolerance-induced type 1 T regulatory cell response. These data suggest that i.v. administration of autoantigen results in the suppression of endogenous IL-12 and the consequent switching of the immune response from an immunogenic to a tolerogenic form.

T cells, cytokines, and autoantigens in multiple sclerosis

In multiple sclerosis (MS), inflammatory demyelination in the central nervous system is thought to be initiated by T cells that recognize myelin antigens. T cells are the main regulators of acquired immunity and are involved in the pathogenesis of several organ-specific autoimmune diseases. This review provides an overview of recent studies on the role of T cells in autoimmune demyelination. Because autoreactive T cells are normally present in the mature repertoire of T cells in the blood and lymphoid organs of MS patients, but also in normal controls, particular attention is devoted to the mechanisms of activation and the functional phenotype of such T cells in patients with MS. The role of cytokines as effector molecules and the main candidate antigens are also discussed.

Il-12 enhances CD8 T cell homeostatic expansion

The size of the T lymphocyte pool is maintained by regulation of T cell production, proliferation, and survival. Under the pressure of a T lymphopenic environment, mature naive T cells begin to proliferate in the absence of Ag, a process called homeostatic expansion. Homeostatic expansion involves TCR recognition of self peptide/MHC ligands, but less is known about the soluble factors that regulate this process. Here we show that IL-12 dramatically enhanced the homeostatic proliferation of CD8 T cells. In contrast, IL-2 had no beneficial effect on homeostatic expansion and, in fact, inhibited T cell expansion induced by IL-12. Using gene-targeted mice, we showed that IL-12 acted directly on the T cells to enhance homeostatic expansion, but that IL-12 cannot override the requirement for TCR interaction with self peptide/MHC ligands in homeostatic expansion. These data indicate that inflammatory cytokines may modulate T cell homeostasis after lymphopenia and have implications for regulation of the T cell repertoire and autoimmunity.