Immune Regulatory 1 Cells: A Novel and Potent Subset of Human T Regulatory Cells.

A subset of T regulatory cells (Tregs), identified by TIRC7 (T cell immune response cDNA 7) expression is designated as Immune Regulatory 1 Cells (IR1 cells). TIRC7 is an immune checkpoint inhibitor, co-localized with the T- cell receptor, HLA-DR and CTLA-4 during T-cell activation, which delivers regulatory signals binding to its ligand, HLA-DR 2 domain. IR1 cells express FOXP3, and multiple other markers associated with immune suppression.

The Transmembrane Receptor TIRC7 Identifies a Distinct Subset of Immune Cells with Prognostic Implications in Cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a heterogeneous malignancy with a dismal prognosis. Therapeutic options are largely limited to surgery and conventional chemotherapy offers limited benefit. As immunotherapy has proven highly effective in various cancer types, we have undertaken a quantitative immunohistopathological assessment of immune cells expressing the immunoinhibitory T cell immune response cDNA 7 receptor (TIRC7), an emerging immunoinhibitory receptor, in a cohort of 135 CCA patients.

Efficacy and Safety of CAP7.1 as Second-Line Treatment for Advanced Biliary Tract Cancers: Data from a Randomised Phase II Study.

CAP7.1 is a novel topoisomerase II inhibitor, converted to active etoposide via carboxylesterase 2 (CES2), with signals of efficacy in treatment-refractory solid tumours. In a Phase II trial, 27 patients with advanced biliary tract cancers (BTC) were randomised 1:1 to CAP7.

A review of systemic therapy in biliary tract carcinoma.

Biliary tract carcinoma (BTC) has a poor prognosis and is increasing in incidence. Although surgery, chemotherapy and other treatment modalities have improved, surgery remains the only potential curative treatment and is appropriate for only those few patients who present with localized, resectable disease. However, for the majority of patients, unresectable disease is evident at diagnosis and about 95% of patients die within 10 years, despite the majority receiving chemotherapy.

Prognostic Impact of Carboxylesterase 2 in Cholangiocarcinoma.

Carboxylesterase 2 (CES2) is instrumental for conversion of ester-containing prodrugs in cancer treatment. Novel treatment strategies are exceedingly needed for cholangiocarcinoma (CCA) patients. Here, we assessed CES2 expression by immunohistochemistry in a CCA cohort comprising 171 non-liver fluke associated, intrahepatic (n = 72) and extrahepatic (perihilar: n = 56; distal: n = 43) CCAs.

Tissue-infiltrating plasma cells are an important source of carboxylesterase 2 contributing to the therapeutic efficacy of prodrugs.

Carboxylesterase 2 (CES-2) is instrumental for conversion of ester-containing prodrugs in cancer treatment. CES-2 expression was analyzed by immunohistochemistry in colorectal cancer (CRC) compared to colonic inflammation as well as in liver and peripheral blood. In CRC, tumor grades showed no correlation with levels of CES-2 expression, which was heterogeneous within these tumors.

Improving the outcomes: developing cancer therapeutics.

Oncology therapeutics are less likely to reach the market than other therapeutics, at a higher cost, and only approximately one in ten cancer drugs in clinical development actually reach the market. To improve, there need to be new approaches to oncology research and development, based on understanding cancer biology and improving preclinical models and clinical trials, such as more use of biomarkers and evaluation of other targets including cancer stem cells and use of combination therapies. Biomarkers can be used to make early go/no-go decisions in drug development and can speed up drug development by selecting patients who will benefit and excluding patients likely to experience severe side effects, but they need validation before use.

Adiponectin is a negative regulator of antigen-activated T cells.

Adiponectin (APN), a cytokine constitutively produced in fat tissue, has been shown to exert anti-inflammatory effects in various disease models. While the influence of APN on monocytic cells has been extensively studied in vitro, little is known about its role in T cells. In this study, we show that while <10% of human peripheral blood T cells express adiponectin receptors (AdipoRs) on their surface, most T cells store AdipoRs in intracellular compartments.

New approaches to treat cancer - what they can and cannot do.

Delivering drugs directly to tumors and overcoming drug resistance are two hurdles that face cancer researchers. Here's a look at where cancer treatment stands.

HLA-DR alpha 2 mediates negative signalling via binding to Tirc7 leading to anti-inflammatory and apoptotic effects in lymphocytes in vitro and in vivo.

Classically, HLA-DR expressed on antigen presenting cells (APC) initiates lymphocyte activation via presentation of peptides to TCR bearing CD4+ T-Cells. Here we demonstrate that HLA-DR alpha 2 domain (sHLA-DRalpha2) also induces negative signals by engaging TIRC7 on lymphocytes. This interaction inhibits proliferation and induces apoptosis in CD4+ and CD8+ T-cells via activation of the intrinsic pathway.

T-cell immune response cDNA 7 in allograft rejection and inflammation.

The membrane protein T-cell immune response cDNA 7 (TIRC7) is transiently expressed in subsets of lymphocytes following antigen stimulation. The importance of TIRC7 in immune activation is demonstrated by the effect of antibodies directed against extracellular domains of TIRC7. In vitro targeting of TIRC7 inhibits proliferation and cytokine expression in human, mouse and rat lymphocytes, and these inhibitory effects have been associated with induction of cytotoxic T-lymphocyte antigen 4 mRNA and protein in the presence of TIRC7 antibodies.

TIRC7 is induced in rejected human kidneys and anti-TIRC7 mAb with FK506 prolongs survival of kidney allografts in rats.

TIRC7 delivers essential signals during immune activation as antibodies targeting TIRC7 inhibit lymphocyte proliferation and Th1 cytokine expression in vitro and prolonged kidney and heart allograft survival in vivo. Immunohistochemical analysis of biopsy specimens from human renal allografts undergoing rejection despite treatment with Calcineurin inhibitors (CI) showed elevated TIRC7 expression. Accordingly, with a view to clinical application, we evaluated the therapeutic effect of a chimerized anti-TIRC7 mAb in combination with Tacrolimus (FK506) using a rat kidney transplantation model (DA to Lewis).

TIRC7 inhibits T cell proliferation by modulation of CTLA-4 expression.

Ab targeting of TIRC7 has been shown previously to inhibit T cell proliferation and Th1 lymphocyte-associated cytokine production. In this study, we demonstrate that Ab targeting of TIRC7 induces early cell surface expression of CTLA-4. The majority of stimulated CD4+ and CD8+ human T cells coexpress CTLA-4 and TIRC7.

TIRC7 pathway as a target for preventing allograft rejection.

A number of leukocyte surface molecules play an essential role during immune activation. Targeting of these molecules utilizing antibodies serves as a specific therapeutic approach for the treatment of a variety of human diseases. Antibodies targeting a number of leukocyte surface molecules were shown to induce tolerance to transplants in several animal models.

TIRC7 deficiency causes in vitro and in vivo augmentation of T and B cell activation and cytokine response.

The membrane protein T cell immune response cDNA 7 (TIRC7) was recently identified and was shown to play an important role in T cell activation. To characterize the function of TIRC7 in more detail, we generated TIRC7-deficient mice by gene targeting. We observed disturbed T and B cell function both in vitro and in vivo in TIRC7(-/-) mice.

Monoclonal antibody specific for TIRC7 induces donor-specific anergy and prevents rejection of cardiac allografts in mice.

T cell immune response c-DNA (TIRC7) is up-regulated during the early stages of T-cell activation in response to alloantigens. In this study, we analyzed the effects of newly developed monoclonal antibodies (mAb) against TIRC7 in acute cardiac allograft rejection. Fully vascularized heterotopic allogeneic heart transplantation was performed in mice across a full-mismatch barrier (C57Bl/10 into CBA).

Carcinoembryonic antigen-related cellular adhesion molecule 1 isoforms alternatively inhibit and costimulate human T cell function.

Carcinoembryonic Ag-related cellular adhesion molecule 1 (CEACAM1) represents a group of transmembrane protein isoforms that consist of variable numbers of extracellular Ig-like domains together with either a long cytoplasmic (cyt) tail containing two immunoreceptor tyrosine-based inhibitory motifs or a unique short cyt tail. Although CEACAM1 has been reported to be expressed on the surface of T lymphocytes upon activation, its roles in T cell regulation are controversial due to the lack of functional characterization of each individual CEACAM1 isoform. We thus cotransfected Jurkat T cells with CEACAM1 isoform-encoding constructs and an IL-2 promoter-bearing plasmid or a small interference RNA targeting src homology domain 2 containing phosphatase 1.

Specific regulation of T helper cell 1-mediated murine colitis by CEACAM1.

Carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1) is a cell surface molecule that has been proposed to negatively regulate T cell function. We have shown that CEACAM1 is associated with specific regulation of T helper cell (Th)1 pathways, T-bet-mediated Th1 cytokine signaling, and Th1-mediated immunopathology in vivo. Mice treated with anti-mouse CEACAM1-specific monoclonal antibody (mAb) CC1 during the effector phase exhibited a reduced severity of trinitrobenzene sulfonic acid colitis in association with decreased interferon (IFN)-gamma production.