Interleukin-2 Receptor Beta Chain Research Articles

Abstract A077: A novel, tumor-targeted immunocytokine comprising an anti-PD-L1 Affimer® fused to IL-15 exhibits potent anti-tumor activity

Abstract Affimer® biotherapeutics are novel 15kDa scaffold proteins based on the human protease inhibitor Stefin A. Affimer® proteins lack disulfide bonds and post translational modifications including glycosylation. Large, diverse phage display libraries have been created which incorporate peptide loops into the scaffold backbone. We have previously identified high-affinity competitive binders to human programmed death-ligand 1 (PD-L1) using phage display which block interaction with programmed death 1 (PD-1). Lead anti-PD-L1 Affimer® proteins were formatted by fusing to human Fc or as in-line-fusions to a serum albumin binding Affimer® to extend pharmacokinetic half-life. Here we describe novel immunocytokines that consist of half-life extended Affimer® antagonist to PD-L1 fused to human Interleukin 15 (IL-15) receptor alpha sushi domain and human IL-15 (PDL1-IL15 Affimer® fusion proteins). PD-L1 is upregulated on tumor cells, macrophages, and dendritic cells in the tumor microenvironment. PD-L1 engagement with PD-1 on T cells inhibits T cell proliferation, transcriptional activation, and cytokine release, resulting in suppressed anti-tumor response. IL-15 signals through the IL-2 receptor beta chain and the common gamma chain (IL-2Rβ/γ) and induces differentiation and proliferation of CD8+ T cells and Natural Killer (NK) cells; it does not stimulate regulatory T cells (Tregs). Immunostimulatory cytokines have therapeutic potential but are often associated with toxicity when administered systemically. PDL1-IL15 Affimer® fusion proteins have the potential to bring the immunomodulatory cytokine directly to the tumor and reverse the immunosuppressive tumor microenvironment by enhancing T cell activation, while also introducing a checkpoint inhibitor to augment the anti-tumor immune response. We characterized binding and activity of PDL1-IL15 Affimer® fusion proteins in in vitro assays. PDL1-IL15 Affimer® fusion proteins bind both PD-L1 and IL-2Rβ/γ and exhibit PD-1:PD-L1 blocking activity and IL-2Rβ/γ activation. PDL1-IL15 Affimer® fusion proteins reversed T cell exhaustion in a human mixed lymphocyte reaction assay: PDL1-IL15 Affimer® fusion proteins showed greater activity than either the PD-L1 or the IL-15 component alone. Furthermore, PDL1-IL15 Affimer® fusion proteins enhanced immune cell killing of tumor cells in co-culture assays of human peripheral blood mononuclear cells and tumor cells. In summary, data suggests that PDL1-IL15 Affimer® fusion proteins can reverse T cell exhaustion and induce immune cell activation to elicit an anti-tumor effect. Ongoing in vivo work aims to investigate the efficacy and tolerability profile of PDL1-IL15 Affimer® fusion proteins to direct future development of this therapeutic. In addition, the data will support wider utility of the Affimer® platform to develop new ways of targeting the tumor while reducing systemic toxicity. Citation Format: Victoria Juskaite, Deepa Avisetti, David H Jones, Ahmad Sobri, Gregory Billenness, Hanna Buist, Tik Nga Tong, Norhakim Yahya, Fiona McLaughlin. A novel, tumor-targeted immunocytokine comprising an anti-PD-L1 Affimer® fused to IL-15 exhibits potent anti-tumor activity [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A077.

Molecular reshaping of phage-displayed Interleukin-2 at beta chain receptor interface to obtain potent super-agonists with improved developability profiles

Interleukin-2 (IL-2) engineered versions, with biased immunological functions, have emerged from yeast display and rational design. Here we reshaped the human IL-2 interface with the IL-2 receptor beta chain through the screening of phage-displayed libraries. Multiple beta super-binders were obtained, having increased receptor binding ability and improved developability profiles. Selected variants exhibit an accumulation of negatively charged residues at the interface, which provides a better electrostatic complementarity to the beta chain, and faster association kinetics. These findings point to mechanistic differences with the already reported superkines, characterized by a conformational switch due to the rearrangement of the hydrophobic core. The molecular bases of the favourable developability profile were tracked to a single residue: L92. Recombinant Fc-fusion proteins including our variants are superior to those based on H9 superkine in terms of expression levels in mammalian cells, aggregation resistance, stability, in vivo enhancement of immune effector responses, and anti-tumour effect.

A tumor-targeted cytokine/antibody fusion protein to stimulate anti-cancer immunity

Abstract Interleukin-2 (IL-2) is a pleiotropic cytokine that has clinical utility in stimulating anti-cancer immunity. However, the clinical efficacy of IL-2 is limited by its short serum half-life, systemic toxicity, and concurrent activation of immunostimulatory natural killer (NK) and effector T (Teff) cells and immunosuppressive regulatory T (Treg) cells. IL-2 can signal down an intermediate-affinity receptor consisting of IL-2 receptor beta (IL-2Rβ) and common gamma chain (γc) or a high-affinity receptor that also includes IL-2Rα. Tregs express high levels of IL-2Rα, making them much more responsive to IL-2 than naïve NK and Teff cells. To extend the serum half-life and selectively bias the immunostimulatory functions of IL-2 in a stable unimolecular format, we created a single-chain fusion protein, denoted F10 immunocytokine (F10 IC), that intramolecularly fuses human IL-2 to an anti-IL-2 antibody that sterically blocks the IL-2/IL-2Rα interaction and allosterically enhances the IL-2/IL-2Rβ interaction. To exploit the abundance and accessibility of collagen in the tumor microenvironment for targeting, we fused collagen binding domains to F10 IC in various topographies. These novel fusion proteins occlude IL-2Rα binding and enhance IL-2Rβ binding, thereby eliminating the Treg advantage conferred by IL-2Rα and preferentially activating immune effector cells. Furthermore, these proteins selectively bind purified collagen and are capable of homing to, and being retained in, the tumor in vivo. Building on these promising results, we are assessing the in vivo therapeutic efficacy of these fusion proteins in various murine tumor models to illustrate the potential of collagen binding F10 IC as a powerful anti-cancer therapeutic. Supported by a Sanofi Innovation Award and NIH grants (R01 EB029341, T32 AI007417)

Cytomegalovirus mediates expansion of IL-15-responsive innate-memory cells with SIV killing function.

Interindividual immune variability is driven predominantly by environmental factors, including exposure to chronic infectious agents such as cytomegalovirus (CMV). We investigated the effects of rhesus CMV (RhCMV) on composition and function of the immune system in young macaques. Within months of infection, RhCMV was associated with impressive changes in antigen presenting cells, T cells, and NK cells-and marked expansion of innate-memory CD8+ T cells. These cells express high levels of NKG2A/C and the IL-2 and IL-15 receptor beta chain, CD122. IL-15 was sufficient to drive differentiation of the cells in vitro and in vivo. Expanded NKG2A/C+CD122+CD8+ T cells in RhCMV-infected macaques, but not their NKG2-negative counterparts, were endowed with cytotoxicity against class I-deficient K562 targets and prompt IFN-γ production in response to stimulation with IL-12 and IL-18. Because RhCMV clone 68-1 forms the viral backbone of RhCMV-vectored SIV vaccines, we also investigated immune changes following administration of RhCMV 68-1-vectored SIV vaccines. These vaccines led to impressive expansion of NKG2A/C+CD8+ T cells with capacity to inhibit SIV replication ex vivo. Thus, CMV infection and CMV-vectored vaccination drive expansion of functional innate-like CD8 cells via host IL-15 production, suggesting that innate-memory expansion could be achieved by other vaccine platforms expressing IL-15.

Human interleukin-2 receptor beta mutations associated with defects in immunity and peripheral tolerance

Abstract Interleukin-2, which conveys essential signals for effective immunity and immunological tolerance, operates through a heterotrimeric receptor. Genetic deficiency of the alpha or gamma chain causes debilitating disease. Here we identify human interleukin-2 receptor (IL-2R) beta chain (IL2RB) gene defects as a cause of life-threatening immune dysregulation. We report three homozygous mutations in the human IL2RB gene of eight individuals from four consanguineous families that cause disease by distinct mechanisms. Nearly all patients presented with autoantibodies, hypergammaglobulinemia, bowel inflammation, dermatological abnormalities, and cytomegalovirus disease. Patient T lymphocytes lacked surface expression of IL-2Rbeta and were unable to respond normally to high-dose IL-2 stimulation. By contrast, patient natural killer (NK) cells retained partial IL-2Rbeta expression and cytotoxic function. IL-2Rbeta loss of function was recapitulated in a recombinant system, in which endoplasmic reticulum sequestration was revealed as the mechanism by which certain missense mutations cause disease. Hematopoietic stem cell transplant resulted in resolution of clinical symptoms in one patient. The hypomorphic nature of this disease highlights the significance of variable IL-2Rbeta expression between different lymphocyte subsets and during their maturation as a means of modulating immune function. Insights from these patients can inform the development of IL-2-based therapeutics for immunological diseases and cancer.

Abstract 3158: Ex vivo expansion and activation of human lymphocytes with a selective activator of effector cells

Abstract RDB 1450 is an engineered fusion protein of circularly permuted IL-2 and IL-2Rα that is selective for the intermediate-affinity IL-2 receptor. The intermediate-affinity receptor is comprised of the IL-2 receptor beta chain (CD122) and common gamma chain (CD132) expressed on lymphocytes with effector function, whereas the high-affinity receptor, which additionally includes the alpha chain (CD25), is expressed primarily on immunosuppressive CD4+CD25+ regulatory T cells (Tregs). Ex vivo proliferation of subsets of human lymphocytes in response to RDB 1450 or rhIL-2 were evaluated. RDB 1450 supports the selective activation and expansion of effector lymphocytes based on higher observed memory CD8 T/Treg and NK/Treg ratios. Both RDB 1450 and IL-2 drive expansion of NK cells, however, a greater proportion of CD25+ NK cells are observed in response to RDB 1450. Furthermore, unlike IL-2, RDB 1450 does not effectively expand highly suppressive ICOS+ Tregs. The immunological profile resulting from the ex vivo treatment of human PBMCs with RDB 1450 supports its use as a novel immunotherapy for cancer. Citation Format: Jared E. Lopes, Jan L. Fisher, Heather C. Losey, Marc S. Ernstoff, Juan C. Alvarez. Ex vivo expansion and activation of human lymphocytes with a selective activator of effector cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3158. doi:10.1158/1538-7445.AM2015-3158

Clarifying off-target effects for torcetrapib using network pharmacology and reverse docking approach

BackgroundTorcetrapib, a cholesteryl ester transfer protein (CETP) inhibitor which raises high-density lipoprotein (HDL) cholesterol and reduces low-density lipoprotein (LDL) cholesterol level, has been documented to increase mortality and cardiac events associated with adverse effects. However, it is still unclear the underlying mechanisms of the off-target effects of torcetrapib.ResultsIn the present study, we developed a systems biology approach by combining a human reassembled signaling network with the publicly available microarray gene expression data to provide unique insights into the off-target adverse effects for torcetrapib. Cytoscape with three plugins including BisoGenet, NetworkAnalyzer and ClusterONE was utilized to establish a context-specific drug-gene interaction network. The DAVID functional annotation tool was applied for gene ontology (GO) analysis, while pathway enrichment analysis was clustered by ToppFun. Furthermore, potential off-targets of torcetrapib were predicted by a reverse docking approach. In general, 10503 nodes were retrieved from the integrative signaling network and 47660 inter-connected relations were obtained from the BisoGenet plugin. In addition, 388 significantly up-regulated genes were detected by Significance Analysis of Microarray (SAM) in adrenal carcinoma cells treated with torcetrapib. After constructing the human signaling network, the over-expressed microarray genes were mapped to illustrate the context-specific network. Subsequently, three conspicuous gene regulatory networks (GRNs) modules were unearthed, which contributed to the off-target effects of torcetrapib. GO analysis reflected dramatically over-represented biological processes associated with torcetrapib including activation of cell death, apoptosis and regulation of RNA metabolic process. Enriched signaling pathways uncovered that IL-2 Receptor Beta Chain in T cell Activation, Platelet-Derived Growth Factor Receptor (PDGFR) beta signaling pathway, IL2-mediated signaling events, ErbB signaling pathway and signaling events mediated by Hepatocyte Growth Factor Receptor (HGFR, c-Met) might play decisive characters in the adverse cardiovascular effects associated with torcetrapib. Finally, a reverse docking algorithm in silico between torcetrapib and transmembrane receptors was conducted to identify the potential off-targets. This screening was carried out based on the enriched signaling network analysis.ConclusionsOur study provided unique insights into the biological processes of torcetrapib-associated off-target adverse effects in a systems biology visual angle. In particular, we highlighted the importance of PDGFR, HGFR, IL-2 Receptor and ErbB1tyrosine kinase might be direct off-targets, which were highly related to the unfavorable adverse effects of torcetrapib and worthy of further experimental validation.

Modeling the role of IL2 in the interplay between CD4+ helper and regulatory T cells: studying the impact of IL2 modulation therapies

Several reports in the literature have drawn a complex picture of the effect of treatments aiming to modulate IL2 activity in vivo. They seem to promote indistinctly immunity or tolerance, probably depending on the specific context, dose and timing of their application. Such complexity might derives from the dual role of IL2 on T-cell dynamics. To theoretically address the latter possibility, we develop a mathematical model for helper, regulatory and memory T-cells dynamics, which account for most well-known facts relative to their relationship with IL2. We simulate the effect of three types of therapies: IL2 injections, IL2 depletion using anti-IL2 antibodies and IL2/anti-IL2 immune complexes injection. We focus in the qualitative and quantitative conditions of dose and timing for these treatments which allow them to potentate either immunity or tolerance. Our results provide reasonable explanations for the existent pre-clinical and clinical data and further provide interesting practical guidelines to optimize the future application of these types of treatments. Particularly, our results predict that: (i) Immune complexes IL2/anti-IL2 mAbs, using mAbs which block the interaction of IL2 and CD25 (the alpha chain of IL2 receptor), is the best option to potentate immunity alone or in combination with vaccines. These complexes are optimal when a 1:2 molar ratio of mAb:IL2 is used and the mAbs have the largest possible affinity; (ii) Immune complexes IL2/anti-IL2 mAbs, using mAbs which block the interaction of IL2 and CD122 (the beta chain of IL2 receptor), are the best option to reinforce preexistent natural tolerance, for instance to prevent allograft rejection. These complexes are optimal when a 1:2 molar ratio of mAb:IL2 is used and the mAbs have intermediate affinities; (iii) mAbs anti-IL2 can be successfully used alone to treat an ongoing autoimmune disorder, promoting the re-induction of tolerance. The best strategy in this therapy is to start treatment with an initially high dose of the mAbs (one capable to induce some immune suppression) and then scales down slowly the dose of mAb in subsequent applications.

Differentiation and Persistence of Memory CD8+ T Cells Depend on T Cell Factor 1

T cell factor 1 (TCF-1) is a transcription factor known to act downstream of the canonical Wnt pathway and is essential for normal T cell development. However, its physiological roles in mature CD8(+) T cell responses are unknown. Here we showed that TCF-1 deficiency limited proliferation of CD8(+) effector T cells and impaired their differentiation toward a central memory phenotype. Moreover, TCF-1-deficient memory CD8(+) T cells were progressively lost over time, exhibiting reduced expression of the antiapoptotic molecule Bcl-2 and interleukin-2 receptor beta chain and diminished IL-15-driven proliferation. TCF-1 was directly associated with the Eomes allele and the Wnt-TCF-1 pathway was necessary and sufficient for optimal Eomes expression in naive and memory CD8(+) T cells. Importantly, forced expression of Eomes partly protected TCF-1-deficient memory CD8(+) T cells from time-dependent attrition. Our studies thus identify TCF-1 as a critical player in a transcriptional program that regulates memory CD8 differentiation and longevity.

Pathway analysis comparison using Crohn's disease genome wide association studies

BackgroundThe use of biological annotation such as genes and pathways in the analysis of gene expression data has aided the identification of genes for follow-up studies and suggested functional information to uncharacterized genes. Several studies have applied similar methods to genome wide association studies and identified a number of disease related pathways. However, many questions remain on how to best approach this problem, such as whether there is a need to obtain a score to summarize association evidence at the gene level, and whether a pathway, dominated by just a few highly significant genes, is of interest.MethodsWe evaluated the performance of two pathway-based methods (Random Set, and Binomial approximation to the hypergeometric test) based on their applications to three data sets of Crohn's disease. We consider both the disease status as a phenotype as well as the residuals after conditioning on IL23R, a known Crohn's related gene, as a phenotype.ResultsOur results show that Random Set method has the most power to identify disease related pathways. We confirm previously reported disease related pathways and provide evidence for IL-2 Receptor Beta Chain in T cell Activation and IL-9 signaling as Crohn's disease associated pathways.ConclusionsOur results highlight the need to apply powerful gene score methods prior to pathway enrichment tests, and that controlling for genes that attain genome wide significance enable further biological insight.

Roles of CD122+ Cells in Resistance against Neospora caninum Infection in a Murine Model

Innate cells, such as natural killer (NK) cells and NKT cells, play essential roles as primary effector cells at the interface between the host and parasite until establishment of adaptive immunity. However, the roles of NK and NKT cells in defense against Neospora caninum have not been well clarified. NK and NKT cells were depleted by the treatment with an anti-CD122 (interleukin-2 receptor beta chain) monoclonal antibody (mAb, TM-β1) in vivo. The parasite burden in the brain of mice was promoted by the treatment with anti-CD122 mAb. However, there was no significant difference in the infection rates between controls and the mice treated with anti-asialoGM1 antibody to deplete NK cells. Activation of CD4+ T cells was suppressed in the mice treated with anti-CD122 mAb compared with controls and the mice treated with anti-asialoGM1 antibody. On the other hand, depletion of CD122+ cells or NK cells did not affect the number of activated CD8+ T cells, dendritic cells and B cells following N. caninum infection. These results indicate that CD122+ cells (probably NKT cells) play a crucial role in host defense by activating CD4+ T cells against N. caninum infection.

Sequential Polarization and Imprinting of Type 1 T Helper Lymphocytes by Interferon-γ and Interleukin-12

Differentiation of naive T lymphocytes into type I T helper (Th1) cells requires interferon-gamma and interleukin-12. It is puzzling that interferon-gamma induces the Th1 transcription factor T-bet, whereas interleukin-12 mediates Th1 cell lineage differentiation. We use mathematical modeling to analyze the expression kinetics of T-bet, interferon-gamma, and the IL-12 receptor beta2 chain (IL-12Rbeta2) during Th1 cell differentiation, in the presence or absence of interleukin-12 or interferon-gamma signaling. We show that interferon-gamma induced initial T-bet expression, whereas IL-12Rbeta2 was repressed by T cell receptor (TCR) signaling. The termination of TCR signaling permitted upregulation of IL-12Rbeta2 by T-bet and interleukin-12 signaling that maintained T-bet expression. This late expression of T-bet, accompanied by the upregulation of the transcription factors Runx3 and Hlx, was required to imprint the Th cell for interferon-gamma re-expression. Thus initial polarization and subsequent imprinting of Th1 cells are mediated by interlinked, sequentially acting positive feedback loops of TCR-interferon-gamma-Stat1-T-bet and interleukin-12-Stat4-T-bet signaling.

Spontaneous Endometrial Hyperplasia in the Uteri of IL-2 Receptor Beta-Chain Transgenic Mice

We found frequent and spontaneous proliferation of glandular epithelium and dilated cysts in the uteri of interleukin-2 receptor (IL2R) beta-chain transgenic (Tg2Rbeta) mice. The aim of this study was to examine the involvement of IL2R beta-chain in the pathogenesis of endometrial hyperplasia (EH). Mouse uteri and serum were collected from Tg2Rbeta and normal littermates (NL), which were classified into three groups according to age. The incidence of EH increased in an age-dependent manner in both types of mice. However, in old age, Tg2Rbeta mice showed more serious phenotypes of EH than NL. Immunohistochemical analysis revealed specific localization of IL2R beta-chain in the glandular epithelial cells, with a correlation to the degree of EH, not only in the Tg2Rbeta uteri but also in the NL uteri. Immunoreactions of CD3 and CD25 were detected in the uteri of Tg2Rbeta but were weak in the uteri of NL, and CD25-positive cells were distributed in the endometrial stroma and myometrium in the Tg2Rbeta mice. These findings suggest that the IL2R beta-chain induces growth potential for glandular epithelial cells and an immune-privileged condition mediated by CD25+regulatory-T cells.

Regulation of IL-2β receptor expression and β-chain mRNA by human thymocytes

The high affinity form of the human IL-2 receptor (IL-2R) has two known components, the IL-2R alpha (p55) and the IL-2R beta chain (p75). We have previously shown that recombinant IL-2 (rIL-2) could induce the expression of the alpha-chain (p55) on T cells and thymocytes, and increase this expression following suboptimal activation with concanavalin A (Con A) in combination with IL-2. An increase in the accumulation of IL-2R alpha-specific mRNA induced by rIL-2 in T cells and thymocytes had also been documented. We report here that the expression of IL-2R beta on the cell surface can be demonstrated on human thymocytes by the binding of Mik beta1, a MoAb directed against an epitope of the beta-chain. The IL-2R beta chain is constitutively expressed on freshly isolated thymocytes; this expression can be increased in thymocytes activated with Con A in combination with IL-2 or tetradecanoylphorbol 13-acetate (TPA). Blocking the formation of high affinity receptors with a MoAb directed against the alpha-chain of the receptor results in an increase in the display of IL-2R beta as evidenced by binding of MoAb Mik beta1. The accumulation of IL-2R-beta-specific mRNA is observed in freshly isolated thymocytes and it is increased in thymocytes cultured with rIL-2 alone, with Con A, and further enhanced by the addition of rIL-2 in combination with Con A or with TPA. Cyclosporine (CsA), which inhibits the accumulation of lymphokine-specific mRNA of thymocytes, does not inhibit the induction of the accumulation of IL-2R beta-specific mRNA. This is analogous to its effect on the expression of the alpha-chain (p55), and the accumulation of alpha-chain-specific mRNA.

Interleukin 15 and its receptor.

Interleukin 15 (IL-15) is a member of the four-helix bundle cytokine family that shares many in vitro biological activities with IL-2. Previous work demonstrated that IL-15 utilizes the beta and gamma chains of the IL-2 receptor (IL-2R), and that these are essential for IL-15-mediated signal transduction. However, several lines of evidence indicated the existence of an additional, IL-15-specific receptor component. An IL-15 binding chain was identified on a murine T cell clone, and direct expression cloning was used to isolate the corresponding cDNA. The predicted structure of this protein shows sequence similarity to the IL-2R alpha chain. Transfection of this cDNA into a murine, IL-3-dependent myeloid cell line, 32D-01, conferred IL-15 binding and, together with transfection of the IL-2R beta chain, rendered the cells responsive to IL-15 stimulation. This experiment confirmed that the IL-15 binding chain is part of the IL-15 receptor, and it is designated as the IL-15R alpha subunit. The expression pattern of the IL-15R alpha mRNA is distinct from that of IL-2R alpha mRNA. Recombinant expression of a soluble form of IL-15R alpha demonstrated that it is a potent inhibitor of IL-15 biological activity.

Identification of a novel G245R polymorphism in the IL-2 receptor β membrane proximal domain associated with human visceral leishmaniasis

Binding of the interleukin-2 (IL-2) to the IL-2 receptor (IL-2R) triggers a series of intracellular events culminating in lymphocyte proliferation and differentiation. We report here the identification of a novel G245R polymorphism in the membrane proximal domain of the IL-2 receptor beta chain (IL-2Rbeta). Present at a frequency of 7.2%, the IL-2-Rbeta G245R was identified in a population of Eastern Sudan exposed to a severe outbreak of visceral leishmaniasis (VL), a disease associated with a marked depression of T-cell antigen-specific responses. The location of the G245R polymorphism next to the box1/box2 proximal cytokine receptor homology segment and suggestive genetic association with the development of disease (P=0.043), suggest that it may affect Janus kinase (JAK) association and impair growth signal transduction. However, additional genetic association with a synonymous single nucleotide polymorphism (IL2RB+8777T) suggests that other variations of IL2RB or nearby genes participate in the highly significant linkage with VL at 22q12 previously reported for this population.

Interleukin-2 receptor beta chain locus rearrangement in a T-cell acute lymphoblastic leukemia

A translocation t(1;22)(p13;q13) was detected in a child with T-cell acute lymphoblastic leukemia (T-ALL). FISH studies showed that the breakpoint was located in the 5' part of the interleukin-2 receptor beta chain (IL2RB) locus, but could only be located distal to 1p13.3 on the partner chromosome. This is the first case of the IL2RB locus rearrangement in T-ALL. The localization of the breakpoint suggests that the chromosomal translocation results in deregulation of IL2RB expression.

T Helper 1-Inducing Property of II-27/WSX-1 Signaling Is Required for the Induction of Experimental Colitis

WSX-1, a component of the interleukin (IL)-27 receptor, is a novel class I cytokine receptor with homology to the IL-12 receptor beta2 chain. Initially, WSX-1 signaling was reported to play an important role in the promotion of T helper-1 responses, but recent reports have revealed an anti-inflammatory property in WSX-1 signaling. In the present study, we investigated the role of IL-27/WSX-1 signaling in a murine colitis model, dextran sulfate sodium (DSS) colitis, by using WSX-1 knockout (KO) mice. First, we observed whether WSX-1 KO mice developed colitis spontaneously. Second, we induced DSS colitis in WSX-1 KO and wild-type (WT) mice. WSX-1 KO mice were observed not to develop colitis spontaneously. The severity of DSS colitis was decreased in WSX-1 KO mice in comparison with WT mice in association with a reduced production of interferon-gamma, IL-6, and tumor necrosis factor-alpha by lamina propria mononuclear cells from WSX-1 KO mice and the absence of T-bet expression in the colon from WSX-1 KO mice. This study revealed the inflammatory property of IL-27/WSX-1 signaling in intestinal inflammation. As a result, IL-27/WSX-1 signal pathway may thus be a promising candidate for the therapeutic intervention of human inflammatory bowel diseases such as Crohn's disease and ulcerative colitis.

A distinct role for ICOS-mediated co-stimulatory signaling in CD4+ and CD8+ T cell subsets

While the ligand of inducible co-stimulator (ICOS), B7 homologous protein, is widely expressed in somatic cells, B7-1 and B7-2 expression is mainly limited to lymphoid organs. Thus, the activation of T cells through ICOS without a CD28-mediated signal may occur in physiological situations. In order to gain a better understanding of the role of the ICOS co-stimulatory signal in immune responses, we studied the cellular response of T cells to beads coated with anti-ICOS or anti-CD28, plus sub-optimal anti-CD3 mAb. We demonstrate that while CD28 ligation induced expansion of both CD4+ and CD8+ populations, ICOS ligation only resulted in the expansion of CD8+ T cells, and induced apoptosis in the CD4+ T cell population. It was found that IL-2 is critically required for CD8+ T cell expansion triggered by ICOS ligation, whereas it had only a limited effect on the expansion of CD4+ T cells. This distinct reactivity of CD4+ and CD8+ T cell populations to exogenous IL-2 strongly correlates with the expression level of IL-2 receptor beta-chain, CD122, on T cells. Furthermore, we defined a small but distinct population of memory phenotype CD4+ T cells that constitutively express ICOS. Interestingly, while naive CD4+ T cells were unable to produce IL-2, ICOS-expressing T cells produced a substantial amount of IL-2 by stimulation with anti-ICOS/CD3 beads, suggesting that IL-2, which is indispensable for CD8+ T cell expansion, is produced by this ICOS-expressing T cell population. These results provide evidence indicating that the ICOS co-stimulatory signal plays a distinct role in the development of CD4+ and CD8+ T cell-mediated immune responses.

Aberrant regulation of interleukin‐12 receptor β2 chain on type 1 cytokine‐stimulated T lymphocytes in type 1 diabetes

An aberrant mitogen-induced polarization of peripheral blood T cells has been associated with type 1 diabetes (T1D). We studied, in T1D, type 1 and 2 cytokine-induced expression of the interleukin-12 receptor beta2 chain (IL-12Rbeta2 chain), which plays a critical role in regulating T-cell polarization. Peripheral blood lymphocytes from children with newly diagnosed T1D (n=10; mean age 10 years), from children with longstanding T1D (n=8; mean age 12.9 years) and from healthy children (n=15; mean age 11.5 years) were stimulated with phytohaemagglutinin (PHA) in a type 1 (IL-12 and anti-IL-4) or a type 2 (IL-4 and anti-IL-12) cytokine environment. Secretion of interferon-gamma (IFN-gamma), IL-5 and IL-13, as detected by enzyme-linked immunosorbent assay (ELISA), and expression of the IL-12Rbeta2 chain on CD4 and CD8 cells by flow cytometry, were analysed. Children with newly diagnosed and longstanding T1D had lower expression levels of the IL-12Rbeta2 chain on IL-12Rbeta2 chain-positive CD4 T cells (for a type 1 or a type 2 cytokine environment: P=0.01 and P=0.002 or P=0.02 and P=0.01, respectively) and on IL-12Rbeta2 chain-positive CD8 T cells (for a type 1 or a type 2 cytokine environment: P=0.007 and P=0.0007 or P=0.003 and P=0.01, respectively) when compared to healthy children. A decreased percentage of IL-12Rbeta2 chain-expressing CD4 T cells (P=0.07 and P=0.03) and CD8 T cells (P=0.004 and P=0.01) and increased secretion of IL-13 (P=0.006 and P=0.04) in a type 1 cytokine environment was seen in both groups of patients. Peripheral blood T cells from patients with both newly diagnosed and longstanding T1D showed poor polarization towards type 1 cells.