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Sarcoidosis is a systemic granulomatous disease characterized by non-caseating epithelioid cell granulomas. One of its immunological hallmarks is the differentiation of CD4 + naïve T cells into Th1/Th17 cells, accompanied by the release of numerous pro-inflammatory cytokines. The TL1A/DR3 signaling pathway plays a crucial role in activating effector lymphocytes, thereby triggering pro-inflammatory responses. The primary aim of this investigation was to scrutinize the impact of anti-TL1A monoclonal antibody on the dysregulation of Th1/Th17 cells and granuloma formation in sarcoidosis. Initially, the abnormal activation of the TL1A/DR3 signaling pathway in pulmonary tissues of sarcoidosis patients was confirmed using qPCR and immunohistochemistry techniques. Subsequently, employing a murine model of sarcoidosis, the inhibitory effects of anti-TL1A monoclonal antibody on the TL1A/DR3 signaling pathway in sarcoidosis were investigated through qPCR, immunohistochemistry, and Western blot experiments. The influence of anti-TL1A monoclonal antibody on granulomas was assessed through HE staining, while their effects on sarcoidosis Th1/Th17 cells and associated cytokine mRNA levels were evaluated using flow cytometry and qPCR, respectively. Immunofluorescence and Western blot experiments corroborated the inhibitory effects of anti-TL1A monoclonal antibody on the aberrant activation of the PI3K/AKT signaling pathway in sarcoidosis. The findings of this study indicate that the TL1A/DR3 signaling pathway is excessively activated in sarcoidosis. Anti-TL1A monoclonal antibody effectively inhibit this abnormal activation in sarcoidosis, thereby alleviating the dysregulation of Th1/Th17 cells and reducing the formation of pulmonary granulomas. This effect may be associated with the inhibition of the downstream PI3K/AKT signaling pathway. Anti-TL1A monoclonal antibody hold promise as a potential novel therapeutic intervention for sarcoidosis., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Mucus secretion is an important feature of asthma that highly correlates with morbidity. Current therapies, including administration of mucolytics and anti-inflammatory drugs, show limited effectiveness and durability, underscoring the need for novel effective and longer lasting therapeutic approaches. Here we show that mucus production in the lungs is regulated by the TNF superfamily member 15 (TL1A) acting through the mucus-inducing cytokine IL-13. TL1A induces IL13 expression by innate lymphoid cells leading to mucus production, in addition to promoting airway inflammation and fibrosis. Reciprocally, neutralization of IL13 signaling through its receptor (IL4Rα), completely reverses TL1A-induced mucus secretion, while maintaining airway inflammation and fibrosis. Importance of TL1A is further demonstrated using a preclinical asthma model induced by chronic house dust mite exposure where TL1A neutralization by genetic deletion or antagonistic blockade of its receptor DR3 protected against mucus production and fibrosis. Thus, TL1A presents a promising therapeutic target that out benefits IL13 in reversing mucus production, airway inflammation and fibrosis, cardinal features of severe asthma in humans., Competing Interests: Authors KS, AM, and RS were employed by Kyowa Kirin Pharmaceutical Research, Inc. The authors declare that this study received funding from Kyowa Kirin Pharmaceutical Research, Inc. Authors KS, AM, and RS of Kyowa Kirin Pharmaceutical Research, Inc participated in discussing results and editing the manuscript. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Steele, Sachen, McKnight, Soloff and Herro.)

Relative control of HIV-1 infection has been linked to genetic and immune host factors. In this study, we analyzed 96 plasma proteome arrays from chronic untreated HIV-1-infected individuals using the classificatory random forest approach to discriminate between uncontrolled disease (plasma viral load [pVL] >50,000 RNA copies/ml; CD4 counts 283 cells/mm 3 , n = 47) and relatively controlled disease (pVL <10,000 RNA copies/ml; CD4 counts 657 cells/mm 3 , n = 49). Our analysis highlighted the TNF molecule's relevance, in particular, TL1A (TNFSF15) and its cognate DR3 (TNFSRF25), both of which increased in the relative virus control phenotype. DR3 levels (in plasma and PBMCs) were validated in unrelated cohorts (including long-term nonprogressors), thus confirming their independence from CD4 counts and pVL. Further analysis in combined antiretroviral treatment (cART)-treated individuals with a wide range of CD4 counts (137-1835 cells/mm 3 ) indicated that neither TL1A nor DR3 levels reflected recovery of CD4 counts with cART. Interestingly, in cART-treated individuals, plasma TL1A levels correlated with regulatory T cell frequencies, whereas soluble DR3 was strongly associated with the abundance of effector HLA-DR + CD8 + T cells. A positive correlation was also observed between plasma DR3 levels and the HIV-1-specific T cell responses. In vitro, costimulation of PBMC with DR3-specific mAb increased the magnitude of HIV-1-specific responses. Finally, in splenocytes of DNA.HTI-vaccinated mice, costimulation of HTI peptides and a DR3 agonist (4C12) intensified the magnitude of T cell responses by 27%. These data describe the role of the TL1A-DR3 axis in the natural control of HIV-1 infection and point to the use of DR3 agonists in HIV-1 vaccine regimens., (Copyright © 2020 by The American Association of Immunologists, Inc.)

Mucosal-associated invariant T (MAIT) cells are semi-invariant T cells specifically recognizing riboflavin derivatives that are synthesized by many bacteria and fungi presented by MHC class I-related MR1 molecules. Accumulating evidence, however, indicates that MAIT cell functions are inducible by cytokine stimuli in the absence of TCR ligation, identifying MAIT cells as innate sentinels in inflammatory environments. In this study, we demonstrate that death receptor 3 (DR3), a member of the TNFR superfamily, is ex vivo expressed and predominantly upregulated on the surface of human MAIT cells by innate cytokine stimulation. In turn, the DR3 ligand TNF-like protein 1A (TL1A) licenses innate TNF-α production in the absence of cognate triggers, being sufficient to promote activation of primary endothelial cells in vitro. TL1A further amplifies synthesis of IFN-γ and granzyme B in the presence of otherwise weak innate stimuli and strongly augments polyfunctionality. Mechanistically, TL1A potentiates T-bet expression, early NF-κB, and late p38 MAP kinase phosphorylation, with the latter being indispensable for TNF-α production by MAIT cells. Of note, endogenous TL1A is also rapidly released from PBMC cultures in response to bacterial triggering, thereby equally augmenting Ag-specific MAIT cell effector functions. In summary, to our knowledge, we identify a new inflammatory mechanism in MAIT cells linking the DR3/TL1A axis with amplification of TCR-dependent and -independent effector functions, particularly inducing excessive innate TNF-α production. Given that both TL1A and TNF-α are abundantly present at sites of chronic inflammation, the contribution of MAIT cells in such scenarios needs to be determined., (Copyright © 2019 by The American Association of Immunologists, Inc.)

TNF-like ligand 1 A (TL1A) and death receptor 3 (DR3) are a ligand-receptor pair involved in the pathogenesis of inflammatory bowel disease. Group 3 innate lymphoid cells (ILC3s) regulate intestinal immunity and highly express DR3. Here, we report that activation of DR3 signaling by an agonistic anti-DR3 antibody increases GM-CSF production from ILC3s through the p38 MAPK pathway. GM-CSF causes accumulation of eosinophils, neutrophils and CD11b + CD11c + myeloid cells, resulting in loss of ILC3s from the intestine in an IL-23-dependent manner and exacerbating colitis. Blockade of GM-CSF or IL-23 reverses anti-DR3 antibody-driven ILC3 loss, whereas overexpression of IL-23 induces loss of ILC3s in the absence of GM-CSF. Neutralization of TL1A by soluble DR3 ameliorates both DSS and anti-CD40 antibody-induced colitis. Moreover, ILC3s are required for the deleterious effect of anti-DR3 antibodies on innate colitis. These findings clarify the process and consequences of DR3 signaling-induced intestinal inflammation through regulation of ILC3s.

Death receptor 3 (DR3) is a tumor necrosis factor receptor superfamily member (TNFRSF25), which is minimally expressed on resting conventional T cells (though readily inducible upon cell activation), yet highly expressed on resting FoxP3 + regulatory T cells (Treg). We recently demonstrated that activation of DR3 with an agonistic antibody (4C12) leads to selective expansion and activation of Treg in healthy mice and suppression of graft-versus-host disease (GVHD) in recipient mice when donor mice are treated. However, given the long antibody half-life and concomitant safety concerns, along with the lack of a humanized agonistic antibody to DR3, both human and murine fusion proteins incorporating the natural DR3 ligand TL1A (TL1A-Ig) have been developed. Herein, we show that DR3 activation with 4C12 or with TL1A-Ig, with or without the addition of low dose IL-2 to the treatment regimen, led to a significant expansion of murine Treg in spleen, lymph nodes, and peripheral blood. Bioluminescent imaging revealed peak Treg expansion around day 7-8, with return to near baseline after 2-3 weeks. In addition to expansion, all DR3 agonist treatment regimens led to increased activation of Tregs, with significant upregulation of the activation markers ICOS, KLRG-1, PD-1, and CD103, and the proliferation marker Ki-67. The near absence of activated Treg populations in control treated spleens was also detected on tSNE analysis of flow cytometry data. Subtly different patterns of splenic Treg activation by the different DR3 agonists were noted in both tSNE analysis of flow cytometry data and RNA-sequencing analysis. However, upregulation of gene transcripts which play important roles in cell proliferation, trafficking, activation, and effector function were observed regardless of the DR3 agonist treatment regimen used. In the major MHC-mismatch model of hematopoietic cell transplantation, DR3 agonist-mediated expansion and activation of Tregs in donor mice led to a significant improvement in GVHD in recipient mice. These data provide important preclinical information regarding the outcome of DR3 activation with an agonistic antibody or natural ligand and provide insight into the therapeutic use of this approach to reduce GVHD in recipients and improve outcomes of hematopoietic cell transplantation.

Atopic dermatitis is an allergic inflammatory skin disease characterized by the production of the type 2 cytokines in the skin by type 2 innate lymphoid cells (ILC2s) and T helper 2 (T H 2) cells, and tissue eosinophilia. Using two distinct mouse models of atopic dermatitis, we show that expression of retinoid-related orphan receptor α (RORα) in skin-resident T regulatory cells (T regs ) is important for restraining allergic skin inflammation. In both models, targeted deletion of RORα in mouse T regs led to exaggerated eosinophilia driven by interleukin-5 (IL-5) production by ILC2s and T H 2 cells. Expression of RORα in skin-resident T regs suppressed IL-4 expression and enhanced expression of death receptor 3 (DR3), which is the receptor for tumor necrosis factor (TNF) family cytokine, TNF ligand-related molecule 1 (TL1A), which promotes T reg functions. DR3 is expressed on both ILC2s and skin-resident T regs Upon deletion of RORα in skin-resident T regs , we found that T regs were no longer able to sequester TL1A, resulting in enhanced ILC2 activation. We also documented higher expression of RORα in skin-resident T regs than in peripheral blood circulating T regs in humans, suggesting that RORα and the TL1A-DR3 circuit could be therapeutically targeted in atopic dermatitis., (Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Death receptor 3 (DR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, has been implicated in regulating T-helper type-1 (T H 1), type-2 (T H 2), and type-17 (T H 17) responses as well as regulatory T cell (T reg ) and innate lymphoid cell (ILC) functions during immune-mediated diseases. However, the role of DR3 in controlling lymphocyte functions in inflammatory bowel disease (IBD) is not fully understood. Recent studies have shown that activation of DR3 signaling modulates T reg expansion suggesting that stimulation of DR3 represents a potential therapeutic target in human inflammatory diseases, including Crohn's disease (CD). In this study, we tested a specific DR3 agonistic antibody (4C12) in SAMP1/YitFc (SAMP) mice with CD-like ileitis. Interestingly, treatment with 4C12 prior to disease manifestation markedly worsened the severity of ileitis in SAMP mice despite an increase in FoxP3 + lymphocytes in mesenteric lymph node (MLN) and small-intestinal lamina propria (LP) cells. Disease exacerbation was dominated by overproduction of both T H 1 and T H 2 cytokines and associated with expansion of dysfunctional CD25 - FoxP3 + and ILC group 1 (ILC1) cells. These effects were accompanied by a reduction in CD25 + FoxP3 + and ILC group 3 (ILC3) cells. By comparison, genetic deletion of DR3 effectively reversed the inflammatory phenotype in SAMP mice by promoting the expansion of CD25 + FoxP3 + over CD25 - FoxP3 + cells and the production of IL-10 protein. Collectively, our data demonstrate that DR3 signaling modulates a multicellular network, encompassing T regs , T effectors, and ILCs, governing disease development and progression in SAMP mice with CD-like ileitis. Manipulating DR3 signaling toward the restoration of the balance between protective and inflammatory lymphocytes may represent a novel and targeted therapeutic modality for patients with CD.

TL1A, a tumor necrosis factor-like cytokine, is a ligand for the death domain receptor DR3. TL1A, upon binding to DR3, can stimulate lymphocytes and trigger secretion of proinflammatory cytokines. Therefore, blockade of TL1A/DR3 interaction may be a potential therapeutic strategy for autoimmune and inflammatory diseases. Recently, the anti-TL1A monoclonal antibody 1 (mAb1) with a strong potency in blocking the TL1A/DR3 interaction was identified. Here, we report on the use of hydrogen/deuterium exchange mass spectrometry (HDX-MS) to obtain molecular-level details of mAb1's binding epitope on TL1A. HDX coupled with electron-transfer dissociation MS provided residue-level epitope information. The HDX dataset, in combination with solvent accessible surface area (SASA) analysis and computational modeling, revealed a discontinuous epitope within the predicted interaction interface of TL1A and DR3. The epitope regions span a distance within the approximate size of the variable domains of mAb1's heavy and light chains, indicating it uses a unique mechanism of action to block the TL1A/DR3 interaction.

Sarcoidosis is a granulomatous disease that primarily affects the lungs and is characterized by an accumulation of CD4 + T cells in the bronchoalveolar lavage (BAL). Previous work has indicated that HLA-DRB1*03:01 + (DR3 + ) patients diagnosed with the acute form of the disease, Löfgren's syndrome (LS), have an accumulation of CD4 + T cells bearing TCRs using TRAV12-1 (formerly AV2S3). However, the importance of these α-chains in disease pathogenesis and the paired TCRβ-chain remains unknown. This study aimed to identify expanded αβTCR pairs expressed on CD4 + T cells derived from the BAL of DR3 + LS patients. Using a deep-sequencing approach, we determined TCRα- and TCRβ-chain usage, as well as αβTCR pairs expressed on BAL CD4 + T cells from LS patients. TRAV12-1 and TRBV2 (formerly BV22) were the most expanded V region gene segments in DR3 + LS patients relative to control subjects, and TRAV12-1 and TRBV2 CDR3 motifs were shared among multiple DR3 + LS patients. When assessing αβTCR pairing, TRAV12-1 preferentially paired with TRBV2, and these TRAV12-1/TRBV2 TCRs displayed CDR3 homology. These findings suggest that public CD4 + TCR repertoires exist among LS patients and that these T cells are recognizing the putative sarcoidosis-associated Ag(s) in the context of DR3., (Copyright © 2017 by The American Association of Immunologists, Inc.)

Th1 cells can be activated by TCR-independent stimuli, but the importance of this pathway in vivo and the precise mechanisms involved require further investigation. Here, we used a simple model of non-cognate Th1 cell stimulation in Salmonella-infected mice to examine these issues. CD4 Th1 cell expression of both IL-18R and DR3 was required for optimal IFN-γ induction in response to non-cognate stimulation, while IL-15R expression was dispensable. Interestingly, effector Th1 cells generated by immunization rather than live infection had lower non-cognate activity despite comparable IL-18R and DR3 expression. Mice lacking T cell intrinsic expression of MyD88, an important adapter molecule in non-cognate T cell stimulation, exhibited higher bacterial burdens upon infection with Salmonella, Chlamydia or Brucella, suggesting that non-cognate Th1 stimulation is a critical element of efficient bacterial clearance. Thus, IL-18R and DR3 are critical players in non-cognate stimulation of Th1 cells and this response plays an important role in protection against intracellular bacteria.

Significant barriers to transplantation exist for individuals who are pre-sensitized to donor antigen and have high titres of donor-reactive antibody. We report the effect of autologous bone marrow transplantation (BMTx) after myeloablation in pre-sensitized mice along with the use of monoclonal antibodies (mAbs) to tumour necrosis factor-receptor super family 25 (TNFRSF25), expressed on regulatory T (Treg) cells. C57BL/6 mice, which had been sensitized earlier with BALB/c skin allografts, received secondary BALB/c grafts after the primary grafts had been rejected. Subsequently, recipient mice underwent myeloablation with cyclophosphamide and busulphan and were injected with T-cell-depleted bone marrow from CD45.1 congenic donors (BMTx). Recipient mice underwent immunosuppressive treatment with rapamycin. A subgroup of mice was also treated with mAbs to TNFRSF25. Control mice were pre-sensitized mice that received cyclophosphamide and busulphan followed by rapamycin. BMTx-treated mice had significantly prolonged skin graft survival versus control mice. These mice also showed attenuated donor-specific mixed lymphocyte co-culture responses relative to controls, increased splenic Treg cells and markedly diminished serum anti-donor IgG. Infusion of anti-TNFRSF25 mAbs further augmented graft survival and increased graft-infiltrating Treg cells. These mAbs also expanded murine and human Treg cells in vitro with the capacity to attenuate mixed lymphocyte co-cultures using fresh peripheral blood mononuclear cells. Overall, this study delineates the roles of autologous BMTx and anti-TNFRSF25 mAbs in expanding Treg cells and attenuating alloimmune responses in pre-sensitized mice., (© 2016 John Wiley & Sons Ltd.)

A number of anti-tumor necrosis factor alpha (TNF-α) biologics have been developed in recent years, such as adalimumab, etanercept, and infliximab for the treatment of chronic inflammatory disorders like rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and psoriasis and several other novel drugs that target TNF-α signaling are still being developed. Indeed, blockade of this pathway seems so important amongst immune-targets that TNF-α targeted therapies will continue to have a significant role in the treatment of chronic inflammation. However, up to 40% of RA and IBD patients do not respond to anti-TNF-α treatment and one possible explanation may be the heterogeneity of chronic inflammatory diseases and a dominance of other significant TNF family members. Indeed, polymorphisms in the TNF family member, TL1A gene, is associated with the development of IBD and increased serum concentrations of TL1A has been demonstrated in patients with various chronic inflammatory disorders. Here, we describe the current knowledge of TL1As immunobiology and present results from human disease, animal models, and pre-clinical intervention studies that point toward development of anti-TL1A therapy as a highly promising strategy for treatment of chronic inflammatory disorders.

Death receptor 3 (DR3, TNFRSF25) is expressed by activated lymphocytes and signaling by its ligand, TL1A, enhances cytokine expression and proliferation. Recent studies show that DR3 is also present on murine type 2 innate lymphoid cells (ILC2s). Here, we show that DR3 is expressed by IL-22-producing human group 3 innate lymphoid cells (ILC3s). Stimulation of ILC3s with exogenous TL1A alone had no impact on cytokine production or proliferation. Addition of TL1A to IL-1β + IL-23 significantly enhanced the amount IL-22 produced by ILC3s as well as the percentage IL-22- and IL-8-producing cells. Addition of TL1A to IL-1β + IL-23 also augmented ILC3 proliferation. Mechanistically, this occurred through the upregulation of CD25 and responsiveness to IL-2 stimulation. The combination of TL1A, IL-1β+ IL-23, and IL-2 expanded ILC3s while IL-1β+ IL-23 did not increase proliferation above controls. After 2 weeks of expansion, ILC3s maintained their phenotype, transcription factor expression, and function (IL-22 production). These findings identify DR3 as a costimulatory molecule on ILC3s that could be exploited for ex vivo expansion and clinical use., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The paucity of regulatory T cells (Tregs) limits clinical translation to control aberrant immune reactions including graft-versus-host disease (GVHD). Recent studies showed that the agonistic antibody to DR3 (αDR3) expanded CD4(+)FoxP3(+) Tregs in vivo. We investigated whether treating donor mice with a single dose of αDR3 could alleviate acute GVHD in a MHC-mismatched bone marrow transplantation model. αDR3 induced selective proliferation of functional Tregs. CD4(+) T cells isolated from αDR3-treated mice contained higher numbers of Tregs and were less proliferative to allogeneic stimuli. In vivo GVHD studies confirmed that Tregs from αDR3-treated donors expanded robustly and higher frequencies of Tregs within donor CD4(+) T cells were maintained, resulting in improved survival. Conventional T cells derived from αDR3-treated donors showed reduced activation and proliferation. Serum levels of proinflammatory cytokines (IFNγ, IL-1β, and TNFα) and infiltration of donor T cells into GVHD target tissues (gastrointestinal tract and liver) were decreased. T cells from αDR3-treated donors retained graft-vs-tumor (GVT) effects. In conclusion, a single dose of αDR3 alleviates acute GVHD while preserving GVT effects by selectively expanding and maintaining donor Tregs. This novel strategy will facilitate the clinical application of Treg-based therapies., (© 2015 by The American Society of Hematology.)

Memory CD4 T cells are strategically positioned at mucosal surfaces to initiate a robust adaptive immune response. The detection of specific antigen via the T-cell receptor causes these memory T cells to unleash a potent antimicrobial response that includes rousing local innate immune populations for tissue-specific defense. Paradoxically, these same memory T cells can also be stimulated by nonantigen-specific signals that are generated by the activity of local innate immune cells. This versatility of mucosal memory T cells in both the initiation and the sensing of local innate immunity could be a vitally important asset during pathogen defense but alternatively could be responsible for initiating and maintaining chronic inflammation in sensitive mucosal tissues.

Recently we identified in a wide spectrum of autoimmune diseases frequently occurring proinflammatory autoantibodies directed against progranulin, a direct inhibitor of TNFR1 & 2 and of DR3. In the present study we investigated the mechanisms for the breakdown of self-tolerance against progranulin. Isoelectric focusing identified a second, differentially electrically charged progranulin isoform exclusively present in progranulin-antibody-positive patients. Alkaline phosphatase treatment revealed this additional progranulin isoform to be hyperphosphorylated. Subsequently Ser81, which is located within the epitope region of progranulin-antibodies, was identified as hyperphosphorylated serine residue by site directed mutagenesis of candidate phosphorylation sites. Hyperphosphorylated progranulin was detected exclusively in progranulin-antibody-positive patients during the courses of their diseases. The occurrence of hyperphosphorylated progranulin preceded seroconversions of progranulin-antibodies, indicating adaptive immune response. Utilizing panels of kinase and phosphatase inhibitors, PKCβ1 was identified as the relevant kinase and PP1 as the relevant phosphatase for phosphorylation and dephosphorylation of Ser81. In contrast to normal progranulin, hyperphosphorylated progranulin interacted exclusively with inactivated (pThr320) PP1, suggesting inactivated PP1 to cause the detectable occurrence of phosphorylated Ser81 PGRN. Investigation of possible functional alterations of PGRN due to Ser81 phosphorylation revealed, that hyperphosphorylation prevents the interaction and thus direct inhibition of TNFR1, TNFR2 and DR3, representing an additional direct proinflammatory effect. Finally phosphorylation of Ser81 PGRN alters the conversion pattern of PGRN. In conclusion, inactivated PP1 induces hyperphosphorylation of progranulin in a wide spectrum of autoimmune diseases. This hyperphosphorylation prevents direct inhibition of TNFR1, TNFR2 and DR3 by PGRN, alters the conversion of PGRN, and is strongly associated with the occurrence of neutralizing, proinflammatory PGRN-antibodies, indicating immunogenicity of this alternative secondary modification., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Mucosal tissues contain large numbers of memory CD4(+) T cells that, through T-cell receptor-dependent interactions with antigen-presenting cells, are believed to have a key role in barrier defense and maintenance of tissue integrity. Here we identify a major subset of memory CD4(+) T cells at barrier surfaces that coexpress interleukin-18 receptor alpha (IL-18Rα) and death receptor-3 (DR3), and display innate lymphocyte functionality. The cytokines IL-15 or the DR3 ligand tumor necrosis factor (TNF)-like cytokine 1A (TL1a) induced memory IL-18Rα(+)DR3(+)CD4(+) T cells to produce interferon-γ, TNF-α, IL-6, IL-5, IL-13, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-22 in the presence of IL-12/IL-18. TL1a synergized with IL-15 to enhance this response, while suppressing IL-15-induced IL-10 production. TL1a- and IL-15-mediated cytokine induction required the presence of IL-18, whereas induction of IL-5, IL-13, GM-CSF, and IL-22 was IL-12 independent. IL-18Rα(+)DR3(+)CD4(+) T cells with similar functionality were present in human skin, nasal polyps, and, in particular, the intestine, where in chronic inflammation they localized with IL-18-producing cells in lymphoid aggregates. Collectively, these results suggest that human memory IL-18Rα(+)DR3(+) CD4(+) T cells may contribute to antigen-independent innate responses at barrier surfaces.

The TNF family cytokine TL1A (Tnfsf15) costimulates T cells and type 2 innate lymphocytes (ILC2) through its receptor DR3 (Tnfrsf25). DR3-deficient mice have reduced T cell accumulation at the site of inflammation and reduced ILC2-dependent immune responses in a number of models of autoimmune and allergic diseases. In allergic lung disease models, immunopathology and local Th2 and ILC2 accumulation is reduced in DR3-deficient mice despite normal systemic priming of Th2 responses and generation of T cells secreting IL-13 and IL-4, prompting the question of whether TL1A promotes the development of other T cell subsets that secrete cytokines to drive allergic disease. In this study, we find that TL1A potently promotes generation of murine T cells producing IL-9 (Th9) by signaling through DR3 in a cell-intrinsic manner. TL1A enhances Th9 differentiation through an IL-2 and STAT5-dependent mechanism, unlike the TNF-family member OX40, which promotes Th9 through IL-4 and STAT6. Th9 differentiated in the presence of TL1A are more pathogenic, and endogenous TL1A signaling through DR3 on T cells is required for maximal pathology and IL-9 production in allergic lung inflammation. Taken together, these data identify TL1A-DR3 interactions as a novel pathway that promotes Th9 differentiation and pathogenicity. TL1A may be a potential therapeutic target in diseases dependent on IL-9., (Copyright © 2015 by The American Association of Immunologists, Inc.)

The study was designed to test DNA Aβ42 immunization in mice as alternative approach for possible active immunotherapy in Alzheimer patients. As results, we found polarized Th2 immune responses, efficient Aβ42 antibody levels, and disappearance of antigen specific T cells. In-vivo TNFRSF4/25 antibody co-stimulation enhanced Aβ42 specific T cell responses with initial Th2 expansion and subsequent development of Aβ42 specific CD4+CD25+Foxp3+ cells. It showed that Th2 biased responses due to gene gun immunizations propagate the development of regulatory T cells. In conclusion, full-length DNA Aβ42 immunization into skin results in a regulatory response with minimal risk of inflammation and autoimmunity., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: CD200 overexpression in transgenic recipients, or by tissue allografts, increases skin and cardiac graft survival in mice receiving rapamycin, in association with increased Foxp3(+)Treg graft infiltration. However, less than 50% of skin grafts persist beyond 25 days. We investigated whether immune ablation using busulphan and cyclophosphamide, followed by autologous marrow reconstitution, would permit long-term survival in a greater percentage of recipients and induce tolerance, allowing for withdrawal of immunosuppressive drugs., Methods: C57BL/6 wild type (BL/6 WT) or CD200(tg) mice received BALB/c skin grafts with rapamycin (1 mg/kg/36 hr) for 7 days. Thereafter, subgroups received busulphan or cyclophospamide for 6 days, followed by BL/6 marrow transplantation (BMTx), whereas controls were maintained on rapamycin. Beginning 7 days after marrow transplantation, mice receiving BMTx also received rapamycin for a further 7, 14, or 21 days (to a maximum of 42 days after transplantation) after which times, all immunosuppressions were withdrawn. Graft survival was monitored throughout, and mixed leukocyte cultures (MLCs) (using peripheral blood leukocytes) were performed for all groups at 60 days after transplantation. Gene expression was performed in grafts harvested at 80 days., Results: Although all WT mice rejected grafts by 16 days, survival in CD200(tg) was approximately 40% at 60 days, with antigen-specific decreased MLC responses to BALB/c. After BMTx, survival in WT mice was greater than 40% at 60 days, and greater than 90% at 60 days in CD200(tg), with corresponding attenuated MLC responses. Long-term surviving grafts were infiltrated by Tregs of both host and donor marrow origins, as defined using CD45 congeneic donors or recipients. Survival was increased by infusion of an antibody directed to TNFRSF25 on Tregs., Conclusion: Autologous BMTx improves graft survival and promotes graft tolerance.

Intestinal fibrostenosis is among the hallmarks of severe Crohn's disease. Patients with certain TNFSF15 (gene name for TL1A) variants over-express TL1A and have a higher risk of developing strictures in the small intestine. In addition, sustained Tl1a expression in mice leads to small and large intestinal fibrostenosis under colitogenic conditions. The aim of this study was to determine whether established murine colonic fibrosis could be reversed with Tl1a antibody (Ab). Treatment with neutralizing Tl1a Ab reversed colonic fibrosis back to the original pre-inflamed levels, potentially as a result of lowered expression of connective tissue growth factor, Il31Ra, transforming growth factor β1 and insulin-like growth factor-1. In addition, blocking Tl1a function by either neutralizing Tl1a Ab or deletion of death domain receptor 3 (Dr3) reduced the number of fibroblasts and myofibroblasts, the primary cell types that mediate tissue fibrosis. Primary intestinal myofibroblasts expressed Dr3 and functionally responded to direct Tl1a signaling by increasing collagen and Il31Ra expression. These data demonstrated a direct role for TL1A-DR3 signaling in tissue fibrosis and that modulation of TL1A-DR3 signaling could inhibit gut fibrosis.

The interaction between TNF-like protein 1A (TL1A) and its receptors, death receptor-3 (DR3) may be involved in the pathogenesis of rheumatoid arthritis (RA) through the regulation of Th17. Our data here showed that TL1A could significantly promote Th17 differentiation and RORc mRNA expression from naive T cells and enhance IL-17A level in cell supernatant in RA patients. Anti-TNF-α treatment had suppressive effects on TL1A-mediated Th17 differentiation and RORc mRNA expression. In addition, The percentage of peripheral CD4+DR3+T cells of RA was significantly higher than that of healthy controls (HC), and this increased percentage of CD4+DR3+T cells was obviously up-regulated when stimulated with anti-CD3 and anti-CD28 antibody in RA patients. However, anti-CD3 and anti-CD28 antibody stimulation did not increase the percentage of CD4+DR3+IL-17A+T cells in RA patients. These results suggested that TL1A could promote Th17 differentiation in RA via the activation of RORc, and this effect may be mediated by the binding of TL1A with DR3., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Analysis of frequency of the occurrence of membrane and soluble forms of the mRNA DR3/LARD in blood in herpesviral infection of various etiology was studied. Four forms of the mRNA DR3/LARD were detected with various frequencies in blood cells of healthy volunteers. Patients with herpesviral infection of various etiology were studied using RT-PCR. Two forms encoded membrane molecules (mRNA LARD 1a, mRNA DR3beta) and two other forms accorded soluble forms of receptor (mRNA LARD 3, mRNA soluble DR3beta). It was revealed that the frequency of the occurrence of mRNA soluble DR3beta form decreased in patients with the varicella zoster virus (VZV) infection in comparison with healthy volunteers. However, the patients with the Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection did not display significant change in occurrence of mRNA soluble DR3beta form. As a whole, changes in frequency of occurrence of spliced variants of mRNA DR3/LARD are directed toward modulation of apoptosis and restraint antiviral immune response.

Purpose of Review: Tumor necrosis factor (TNF)-like cytokine 1A (TL1A) associates with the death receptor 3 (DR3) on activated lymphocytes and induces proinflammatory signals. The decoy receptor 3 (DcR3) competes for TL1A binding and inhibits functional signaling. This review focuses on the role of the TL1A/DR3/DcR3 cytokine system in inflammatory bowel diseases (IBDs)., Recent Findings: TL1A may induce IFN-γ-mediated and IL-17-mediated proinflammatory pathways in IBDs by acting on DR3-expressing, CD4(+)CD161(+) lymphocytes, which are substantially enriched at the inflamed intestinal mucosa. In addition, TL1A/DR3 signaling results in expansion of the Treg pool with concomitant and transient inhibition of their suppressive function. Constitutive expression of TL1A in transgenic mice was associated with small intestinal inflammation, which was accompanied by colonic fibrosis both spontaneously and under colitogenic conditions. Recent human studies demonstrated that soluble TL1A and DcR3 are present in the systemic circulation in patients with active IBD and decline after successful anti-inflammatory treatment., Summary: TL1A/DR3 interactions may participate in the pathogenesis of chronic intestinal inflammation and offer novel therapeutic targets for patients with ulcerative colitis and Crohn's disease.

Ocular infection with herpes simplex virus 1 (HSV-1) results in a chronic immunoinflamammtory reaction in the cornea, which is primarily orchestrated by CD4(+) T cells. Hence, targeting proinflammatory CD4(+) T cells or increasing the representation of cells that regulate their function is a relevant therapeutic strategy. In this report, we demonstrate that effective therapeutic control can be achieved using a combination of approaches under circumstances where monotherapy is ineffective. We use a convenient and highly effective monoclonal antibody (MAb) approach with MAbT25 to expand cells that express the tumor necrosis factor receptor superfamily member 25 (TNFRSF25). In naïve animals, these are predominantly cells that are Foxp3-positive regulatory T cells. MAbT25 treatment before or at the time of initial HSV infection was an effective means of reducing the severity of subsequent stromal keratitis lesions. However, MAbT25 treatment was not effective if given 6 days after infection since it expanded proinflammatory effector T cells, which also express TNFRSF25. Therefore, the MAbT25 procedure was combined with galectin-9 (Gal-9), an approach that compromises the activity of T cells involved in tissue damage. The combination therapy provided highly effective lesion control over that achieved by treatment with one of them. The beneficial outcome of the combination therapy was attributed to the expansion of the regulatory T cell population that additionally expressed activation markers such as CD103 needed to access inflammatory sites. Additionally, there was a marked reduction of CD4(+) gamma interferon-producing effector T cells responsible for orchestrating the tissue damage. The approach that we describe has potential application to control a wide range of inflammatory diseases, in addition to stromal keratitis, an important cause of human blindness.

Background: Thymic-derived Foxp3(+)CD4(+) regulatory T cells (Tregs)-also called natural Tregs-are critical for the induction and maintenance of transplantation tolerance. Using an agonistic tumor necrosis factor-receptor super family (TNFRSF) 25 antibody, clone 4C12, we showed that TNFRSF25 is a powerful regulator of Treg proliferation-mediating expansion of natural Tregs in vivo. In the present study, we investigate the role of Tregs expanded in vivo by TNFRSF25 on cardiac allograft survival in a mouse model of fully major histocompatibility complex-mismatched ectopic heart transplants., Methods: C57BL/6 mice were treated with 20 μg of TNFRSF25 agonist 4C12 4 days before heterotopic allogeneic heart transplantation. The survival of the graft was monitored daily by abdominal palpation until the cessation of cardiac contraction. The severity of immune rejection was evaluated by histopathology. Infiltration of inflammatory cells and Tregs into the graft were characterized by flow cytometry. The expression of cytokines and other regulatory proteins was measured by quantitative real-time polymerase chain reaction., Results: Treatment with 4C12 resulted in expansion of Tregs to 30%-35% of CD4(+) cells and was associated with a significant prolongation of median graft survival from 8 days to 17 days (P=0.0049). On day 7 after transplantation, the time point when controls reject the graft, the transplants of 4C12-treated animals beat strongly and showed increased accumulation of Foxp3(+) Tregs within the graft and decreased infiltration of inflammatory cells., Conclusions: TNFRSF25 agonists expand Tregs in vivo and delay allograft rejection.

Studies have demonstrated that the anti-tumour effect of natural killer (NK) cells is successful for patients with several cancers. Although interleukin-32 (IL-32) is endogenously expressed in NK cells, cytolytic function of NK cells against cancer cells has not been fully demonstrated. In the present study, we found that the growth of cancer cells was suppressed when colon cancer cells or prostate cancer cells were co-cultured with NK-92 cells, an NK cell line. We also found that the expression of tumour necrosis factor receptor 2 and death receptor 3 (DR3) was increased in PC3 cells, and the expression of FAS and DR3 was increased in SW620 cells by co-culture with NK-92 cells. However, cancer cell growth inhibition and IL-32 expression were abolished when cancer cells were co-cultured with NK cells transfected with small interfering (si) RNA of IL-32. DR3 expression was also diminished by co-culture with IL-32-specific siRNA-transfected NK-92 cells. Expression of APO3L, a ligand of DR3, was elevated in NK cells that were co-cultured with cancer cells. It was also found that expression of apoptosis-related proteins such as cleaved caspase-3 and bax was increased in cancer cells co-cultured with NK-92 cells, but their expression was abolished by co-culture with IL-32 siRNA-transfected NK-92 cells. Moreover, knockdown of DR3 in co-culture of NK-92 cells with cancer cells by siRNA or antibodies of DR3 and APO3L reversed the growth inhibitory effect of NK-92 cells. In conclusion, our study showed that IL-32 enhanced the cytotoxic effect of NK-92 cells on the cancer cells through activation of DR3 and caspase-3., (© 2011 The Authors. Immunology © 2011 Blackwell Publishing Ltd.)

DR3 (TNFRSF25) is a member of the tumor necrosis factor receptor (TNFR) superfamily expressed primarily on lymphocytes and is a receptor for the TNF family cytokine TL1A (TNFSF15). DR3 costimulates T-cell activation, but it is unique among these receptors in that it signals through an intracytoplasmic death domain and the adapter protein TRADD (TNFR-associated death domain). TL1A costimulates T cells to produce a wide variety of cytokines and can promote expansion of activated and regulatory T cells in vivo. Studies in mice deficient in DR3 or TL1A or in animals treated with antibodies that block the activity of TL1A have revealed a specific role for DR3 in enhancing effector T-cell proliferation at the site of tissue inflammation in autoimmune disease models. DR3 appears to be required in autoimmune disease models dependent on a variety of different T-cell subsets and also invariant natural killer T (iNKT) cells. Chronic expression of TL1A induces a distinct interleukin-13-dependent pathology in the small intestine marked by goblet cell hyperplasia and other features associated with allergic and anti-parasitic responses. These studies suggest that TL1A may be a viable target for therapies designed to inhibit the T-cell-dependent component of diverse autoimmune diseases., (Published 2011. This article is a US Government work and is in the public domain in the USA.)

TNFRSF25 is a member of the TNF receptor superfamily (TNFRSF) that binds to the TNF-like protein TL1A. Although recent studies have demonstrated a role for TNFRSF25 in regulating CD4(+) T-cell responses, it remains to be determined if TNFRSF25 functions as a costimulatory receptor for CD8(+) T cells. Here, we demonstrate that ectopic expression of TL1A on mouse plasmacytomas promotes elimination of tumor cells in a CD8(+) T-cell-dependent manner and renders mice immune to a subsequent challenge with tumor cells. To gain further insight into the role of TNFRSF25 in CD8(+) T-cell responses, we analyzed the effect of TNFRSF25 triggering on OT-I TCR transgenic T cells. We demonstrate that TNFRSF25 triggering in vivo with soluble TL1A promotes the proliferation and accumulation of antigen-specific CD8(+) T cells as well as their differentiation into CTLs. Furthermore, we show that TNFRSF25 also functions as a costimulatory receptor for memory CD8(+) T cells. Thus, TNFRSF25 triggering enhances the secondary expansion of endogenous antigen-specific memory CD8(+) T cells. Our data suggest that TNFRSF25 agonists, such as soluble TL1A, could potentially be used to enhance the immunogenicity of vaccines that aim to elicit human anti-tumor CD8(+) T cells., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

TNFR-associated death domain protein (TRADD) is a key effector protein of TNFR1 signaling. However, the role of TRADD in other death receptor (DR) signaling pathways, including DR3, has not been completely characterized. Previous studies using overexpression systems suggested that TRADD is recruited to the DR3 complex in response to the DR3 ligand, TNF-like ligand 1A (TL1A), indicating a possible role in DR3 signaling. Using T cells from TRADD knockout mice, we demonstrate in this study that the response of both CD4(+) and CD8(+) T cells to TL1A is dependent upon the presence of TRADD. TRADD knockout T cells therefore lack the appropriate proliferative response to TL1A. Moreover, in the absence of TRADD, both the stimulation of MAPK signaling and activation of NF-κB in response to TL1A are dramatically reduced. Unsurprisingly, TRADD is required for recruitment of receptor interacting protein 1 and TNFR-associated factor 2 to the DR3 signaling complex and for the ubiquitination of receptor interacting protein 1. Thus, our findings definitively establish an essential role of TRADD in DR3 signaling.

The tumor necrosis factor (TNF) superfamily protein TNF-like 1A (TL1A) is the ligand for death receptor 3 (DR3). TL1A is induced on activated dendritic cells (DCs) and its expression has been linked to human inflammatory bowel disease. To address how TL1A might influence intestinal inflammation, we generated transgenic mice that constitutively express TL1A on DCs. TL1A transgenic mice developed striking goblet cell hyperplasia in the ileum that was associated with elevated interleukin (IL)-13 levels in the small intestine. IL-13- and IL-17-producing small intestinal lamina propria T cells were increased in TL1A transgenic mice. TL1A also enhanced regulatory T (Treg) cell turnover in vivo and directly stimulated Treg cell proliferation in vitro. The presence of TL1A attenuated the ability of Treg cells to suppress conventional T cells, an effect that required DR3 signaling in either conventional T cells or Treg cells. Our findings identify mechanisms by which chronic DR3 signaling could promote pathogenesis in inflammatory bowel disease.

Introduction: TL1A (TNFSF15) augments IFN-gamma production by IL-12/IL-18 responsive human T cells. Its ligand, death domain receptor 3 (DR3), is induced by activation on T and NK cells. Although IL-12/IL-18 induces DR3 expression on most NK cells, addition of TL1A minimally increases IFN-gamma production., Methods: (51)Chromium release and flow cytometric analysis were used to determine whether the TL1A-DR3 pathway is implicated in tumor cell lysis. Our aim was to determine whether the TL1A-DR3 pathway is implicated in tumor cell lysis., Results: TL1A had no additional effect on IL-12/IL-18-induced cytotoxicity against an NK-susceptible tumor (K562); however, it promoted cytotoxicity against NK-resistant targets susceptible to lysis only by activated NK cells., Discussion: With IL-12/IL-18 activation, TL1A increased CD107a expression on NK cells which led to enhanced lysis of Daudi by PBMC and purified NK cells. To a lesser degree, TL1A increased lysis of colorectal adenocarcinoma epithelial derived lines (WiDr and SW837) by IL-12/IL-18-activated cells., Conclusion: TL1A increased cytotoxicity of IL-12/IL-18-activated NK cells against target cells dependent on NK activation for lysis and could function in vivo as a key co-activator of NK cytotoxicity.

TL1A, a TNF member implicated in autoimmune diseases, is a transmembrane protein that is processed to release soluble TL1A (TL1A-S). TL1A-S induces a Th1 response, although the functional significance of membrane-bound TL1A (TL1A-M) remains unknown. We generated TL1A-M expression in HEK-293 cells capable of binding DR3-Fc. Co-incubating IL-12/IL-18-primed CD4(+) T cells with HEK-293 cells expressing TL1A-M induced 3-fold increase in IFN-gamma that was blocked by anti-TL1A Ab. These results demonstrate that TL1A-M can bind death domain receptor 3 (DR3) through cell-cell contact to induce downstream IFN-gamma secretion enhancement. Anti-TL1A antibodies designed to treat immune diseases should be verified to block both endogenous TL1A forms., (Copyright 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)

βig-h3, an extracellular matrix protein involved in various biological processes including cellular growth, differentiation, adhesion, migration, and angiogenesis, has been shown to be elevated in various inflammatory processes. Death receptor 3 (DR3), a member of the TNF-receptor superfamily that is expressed on T cells and macrophages, is involved in the regulation of inflammatory processes through interaction with its cognate ligand, TNF-like ligand 1A (TL1A). In order to find out whether the TL1A-induced inflammatory activation of macrophages is associated with the up-regulation of βig-h3 expression, the human acute monocytic leukemia cell line (THP-1) was stimulated with either recombinant human TL1A- or DR3-specific monoclonal antibodies. Stimulation of DR3 up-regulated the intracellular levels as well as the secretion of βig-h3. Utilization of various inhibitors and Western blot analysis revealed that activation of protein kinase C (PKC), extracellular signal-regulated kinase (ERK), phosphoinositide kinase-3 (PI3K), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is required for TL1A-induced βig-h3 expression. PKC appears to be the upstream regulator of PI3K since the presence of PKC inhibitor blocked the phosphorylation of AKT without affecting ERK phosphorylation. On the other hand, suppression of either PI3K or ERK activity resulted in the suppression of IκB phosphorylation. These findings indicate that TL1A can regulate the inflammatory processes through modulation of the βig-h3 expression through two separate pathways, one through PKC and PI3K and the other through ERK, which culminates at NF-κB activation., (Copyright © 2010 Elsevier Inc. All rights reserved.)

The identification of individuals genetically susceptible to cancer calls for preventive measures to minimize the cancer risk in these high-risk populations. Immune prevention is made necessary by the anticipated health threat, but lack of enough high-affinity T cells against tumor-associated antigens and the unpredictability of tumor antigens make antigen-based immune prevention untenable for cancer. To address this issue, we explored a non-antigen-based cancer immune prevention strategy using the transgenic adenocarcinoma of mouse prostate model that spontaneously develops prostate cancer with 100% penetrance. We show that targeted mutation of the lymphotoxin alpha (LTalpha) gene efficiently rescued tumor-reactive T cells, drastically reduced cancer incidence, and almost completely ablated metastasis. Remarkably, short-term treatments with the fusion protein consisting of constant region of IgG and extracellular domain of lymphotoxin beta receptor (LTbetaRIg) interrupted clonal deletion, reduced the size of the primary cancer, and completely prevented metastasis later in life. Our data demonstrated the value of non-antigen-based immune prevention for those with a genetic predisposition to cancer.

Background: The HLA-B8, DR3 haplotype has been associated with high immune reactivity. In this study, we have tested whether this haplotype has differential effect on graft survival in patients with IgAN compared with control patients., Methods: From the Eurotransplant Registry we analyzed graft survival of 1207 recipients with IgAN and 7935 control patients with non-glomerular diseases. Death-censored graft loss according to the HLA-B8, DR3 haplotype was calculated with Kaplan-Meier analysis and Cox-regression model was used to correct for various risk factors., Results: The frequency of the HLA-B8, DR3 haplotype was significantly lower in IgAN patients compared with controls (10.3% vs. 15.4%, p < 0.001). Ten-year graft survival was identical in the control group with and without the HLA-B8, DR3 haplotype (71.1% and 70.2%, respectively), but significantly worse in IgAN patients carrying the HLA-B8, DR3 haplotype compared with patients without it (52.5% vs. 69.1%, respectively, p = 0.009). The risk of graft loss was increased by 66% (HR 1.6, 95% CI 1.14, 2.29) in IgAN with the HLA-B8, DR3 haplotype and independent of well-known risk factors., Conclusions: We have identified a new risk factor for graft loss unique to patients with IgAN. This finding emphasizes the exclusive immune characteristics of IgAN patients after transplantation.

DR3 (TRAMP, LARD, WSL-1, TNFRSF25) is a death-domain-containing tumor necrosis factor (TNF)-family receptor primarily expressed on T cells. TL1A, the TNF-family ligand for DR3, can costimulate T cells, but the physiological function of TL1A-DR3 interactions in immune responses is not known. Using DR3-deficient mice, we identified DR3 as the receptor responsible for TL1A-induced T cell costimulation and dendritic cells as the likely source for TL1A during T cell activation. Despite its role in costimulation, DR3 was not required for in vivo T cell priming, for polarization into T helper 1 (Th1), Th2, or Th17 effector cell subtypes, or for effective control of infection with Toxoplasma gondii. Instead, DR3 expression was required on T cells for immunopathology, local T cell accumulation, and cytokine production in Experimental Autoimmune Encephalomyelitis (EAE) and allergic lung inflammation, disease models that depend on distinct effector T cell subsets. DR3 could be an attractive therapeutic target for T cell-mediated autoimmune and allergic diseases.

We identify the tumor necrosis factor receptor superfamily 25 (TNFRSF25)/TNFSF15 pair as critical trigger for allergic lung inflammation, which is a cardinal feature of asthma. TNFRSF25 (TNFR25) signals are required to exert T helper cell 2 (Th2) effector function in Th2-polarized CD4 cells and co-stimulate interleukin (IL)-13 production by glycosphingolipid-activated NKT cells. In vivo, antibody blockade of TNFSF15 (TL1A), which is the ligand for TNFR25, inhibits lung inflammation and production of Th2 cytokines such as IL-13, even when administered days after airway antigen exposure. Similarly, blockade of TNFR25 by a dominant-negative (DN) transgene, DN TNFR25, confers resistance to lung inflammation in mice. Allergic lung inflammation-resistant, NKT-deficient mice become susceptible upon adoptive transfer of wild-type NKT cells, but not after transfer of DN TNFR25 transgenic NKT cells. The TNFR25/TL1A pair appears to provide an early signal for Th2 cytokine production in the lung, and therefore may be a drug target in attempts to attenuate lung inflammation in asthmatics.

The immune phenotype of the partial remission phase or "honeymoon phase" of type 1 diabetes is not well defined. We compared flow cytometry and cytokine production by ELISPOT assays in children with newly diagnosed type 1 diabetes and children in the partial remission phase of type 1 diabetes. Newly diagnosed children had higher levels of FoxP3 expression in CD4 CD25 double positive cells (56.1%+/-24.9 vs. 24.9%+/-24.6 p=0.03) and higher mean numbers of IL-10 producing cells (7.3 cells/2x10(5) cells+/-6.6 vs. 0.86 cells/2x10(5)+/-0.36 p=0.0043) compared to partial remission patients. Higher FoxP3 expression at diagnosis predicted worse future glycemic control while higher mean numbers of IL-10 cells were associated with better future glucose control. These data provide an immune phenotype of the honeymoon phase and suggest that analyzing IL-10 and FoxP3 at diagnosis may identify patients that will experience better glucose control.

Tumor necrosis factor (TNF) and lymphotoxin alpha (LT-alpha) are immunomodulators that have been hypothesized to contribute to susceptibility to type 1 diabetes (T1D). Several polymorphisms in the TNF and LT-alpha loci have been extensively studied for T1D association, with conflicting reports. In this study, we examined two TNF variants and one LT-alpha variant for T1D association in 283 Caucasian, multiplex T1D families for which complete human leukocyte antigen (HLA) genotyping data are available. Initially, association with T1D was seen for LT-alpha A1069G (intron A, p=0.011, rs909253) and TNF G(-308)A (p<1x10(-5), rs1800629), but no association was observed for TNF G(-238)A (rs361525). After adjusting the data for linkage disequilibrium (LD) with DRB1-DQB1 haplotypes, however, only one polymorphism, TNF G(-238)A showed significant association with T1D (p<0.006). When HLA-DR3 haplotypes were examined, the A allele of TNF G(-238)A was significantly overtransmitted to affected offspring (p<0.009). Including HLA-B data in the analysis revealed that TNF (-238)A is present exclusively on DR3 haplotypes that also carry HLA-B18. Transmission proportion of B18-DR3 haplotypes did not differ between those with TNF (-238)A and those with TNF (-238)G. Thus, variation at TNF does not affect the T1D risk for B18-DR3 haplotypes, and the apparent association of TNF(-238)A with T1D may simply reflect its presence on a high-risk haplotype.