Importance of peroxisome proliferator-activated receptor-gamma in hepatic ischemia/reperfusion injury in mice.

Background/aims: Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a transcriptional factor belonging to the nuclear receptor superfamily. Recent studies have suggested that PPARgamma regulates inflammatory responses and PPARgamma specific agonists have beneficial effects on several disease conditions in the various organs. However, the precise role of PPARgamma in acute liver injury remains unknown.

Clinical significance and therapeutic potential of the programmed death-1 ligand/programmed death-1 pathway in human pancreatic cancer.

Purpose: The programmed death-1 ligand/programmed death-1 (PD-L/PD-1) pathway has been recently suggested to play a pivotal role in the immune evasion of tumors from host immune system. In this study, we tried to reveal the clinical importance and therapeutic potential of the PD-L/PD-1 pathway in pancreatic cancer, which is one of the most aggressive and intractable malignant tumors.

Experimental Design: We used immunohistochemistry to investigate PD-L expression in 51 patients with pancreatic cancer who underwent surgery and explored the therapeutic efficacy of blocking the PD-L1/PD-1 pathway in murine pancreatic cancer in vivo.

A potent antiangiogenic factor, endostatin prevents the development of asthma in a murine model.

Background: Clinical studies suggest a role for angiogenesis in the development and persistence of chronic asthma, but whether angiogenic mediators contribute to acute asthma has not been fully studied.

Objective: The aim of this study was to investigate a role of vascular endothelial growth factor (VEGF), a major angiogenic and proinflammatory mediator, in allergen-induced acute asthma and to determine whether endostatin/Fc, a potent antiangiogenic factor can attenuate allergic airway responses.

Methods: We sensitized BALB/c mice with ovalbumin.

Function of the vascular endothelial growth factor receptors Flt-1 and Flk-1/KDR in the alloimmune response in vivo.

Background: We have recently reported that vascular endothelial growth factor (VEGF) functions as a proinflammatory cytokine to regulate the trafficking of leukocytes into allografts in the early posttransplant period. VEGF binds two major VEGF receptors: VEGFR-1 (flt-1) and VEGFR-2 (flk-1/KDR). Here, we wished to investigate the expression and function of VEGF receptors in the process of acute allograft rejection in vivo.

Requirements for induction and maintenance of peripheral tolerance in stringent allograft models.

Peripheral tolerance can be achieved in many but not all murine allograft models. The requirements for controlling more aggressive immune responsiveness and generating peripheral tolerance in stringent allograft models are unknown. Understanding these requirements will provide insight toward ultimately achieving tolerance in humans, which are also resistant.

Significance and therapeutic potential of prostaglandin E2 receptor in hepatic ischemia/reperfusion injury in mice.

Prostaglandin E2 (PGE2) mediates a variety of innate and adaptive immunity through four distinct receptors: EP1-EP4. It has been suggested that each EP plays a unique and pivotal role in various disease conditions. We investigated the pathophysiological role of EP receptors in hepatic ischemia/reperfusion (I/R) injury.

A novel small-molecule compound targeting CCR5 and CXCR3 prevents acute and chronic allograft rejection.

Background: Chemokines and chemokine receptors are critical in leukocyte recruitment, activation, and differentiation. Among them, CC chemokine receptor 5 (CCR5) and CXC chemokine receptor 3 (CXCR3) have been reported to play important roles in alloimmune responses and may be potential targets for posttransplant immunosuppression.

Methods: Fully major histocompatibility complex (MHC)-mismatched murine cardiac and islet transplant models were used to test the effect in vivo of a novel, small-molecule compound TAK-779 by targeting CCR5 and CXCR3 in acute allograft rejection.

Dual role of vascular endothelial growth factor in hepatic ischemia-reperfusion injury.

Background: Vascular endothelial growth factor (VEGF), a major angiogenic factor, mediates a variety of disease conditions through promotion of angiogenesis. It also plays a critical role as a potent proinflammatory cytokine in a variety of physiologic and pathologic immune responses. In the present study, we evaluated the expression of VEGF in hepatic warm ischemia-reperfusion (I/R) injury and examined the effect of recombinant human (rh)VEGF administration in an established murine model.

Role of the ICOS-B7h costimulatory pathway in the pathophysiology of chronic allograft rejection.

Background: Inducible costimulator (ICOS) is the third member of the CD28 superfamily and has a unique role in T cell activation and function. Recent studies indicated that the ICOS-B7h pathway plays an important role in alloimmune responses. We further investigated the role of the ICOS pathway in the pathologic process of chronic rejection in vivo.

Clinical significance of programmed death-1 ligand-1 and programmed death-1 ligand-2 expression in human esophageal cancer.

Purpose: The negative regulatory programmed death-1/programmed death-1 ligand (PD-1/PD-L) pathway in T-cell activation has been suggested to play an important role in tumor evasion from host immunity. In this study, we investigated the expression of PD-L1 and PD-L2 in human esophageal cancer to define their clinical significance in patients' prognosis after surgery.

Experimental Design: PD-L1 and PD-L2 gene expression was evaluated in 41 esophagectomy patients by real-time quantitative PCR.

CD70 signaling is critical for CD28-independent CD8+ T cell-mediated alloimmune responses in vivo.

The inability to reproducibly induce robust and durable transplant tolerance using CD28-B7 pathway blockade is in part related to the persistence of alloreactive effector/memory CD8(+) T cells that are less dependent on this pathway for their cellular activation. We studied the role of the novel T cell costimulatory pathway, CD27-CD70, in alloimmunity in the presence and absence of CD28-B7 signaling. CD70 blockade prolonged survival of fully mismatched vascularized cardiac allografts in wild-type murine recipients, and in CD28-deficient mice induced long-term survival while significantly preventing the development of chronic allograft vasculopathy.

Bone marrow chimerism and tolerance induced by single-dose cyclophosphamide.

Background: Establishment of hematopoietic chimerism is the most stable strategy for donor-specific tolerance. Safer pretreatment regimens are needed for clinical application. We evaluated the efficacy of a simple protocol using cyclophosphamide (CYP) on induction of chimerism and organ transplant tolerance across major histocompatibility complex (MHC) barriers in the rat.

[Current status and prospect of T cell costimulatory blockade in transplantation].

Organ transplantation has been widely accepted as a routine medical treatment in Japan. The recent introduction of new immunosuppressive reagents may improve outcome after transplantation. However, further investigations are required to achieve the prevention of chronic rejection and the induction of donor-specific tolerance in clinical transplantation.

Prognostic significance of localized p27Kip1 and potential role of Jab1/CSN5 in pancreatic cancer.

p27Kip1 belongs to the family of small polypeptides collectively termed cyclin-dependent kinase inhibitors, which negatively regulate the cell cycle progression. In various human cancers, the reduced p27Kip1 expression correlates well with poor prognosis. Recently, Jab1/CSN5, the fifth component of the COP9 signalosome complex, was found to specifically translocate p27Kip1 from the nucleus to the cytoplasm, and reduce the protein level of p27Kip1 by accelerating its degradation.

Proinflammatory functions of vascular endothelial growth factor in alloimmunity.

Vascular endothelial growth factor (VEGF), an established angiogenesis factor, is expressed in allografts undergoing rejection, but its function in the rejection process has not been defined. Here, we initially determined that VEGF is functional in the trafficking of human T cells into skin allografts in vivo in the humanized SCID mouse. In vitro, we found that VEGF enhanced endothelial cell expression of the chemokines monocyte chemoattractant protein 1 and IL-8, and in combination with IFN-gamma synergistically induced endothelial cell production of the potent T cell chemoattractant IFN-inducible protein-10 (IP-10).

Favorably tipping the balance between cytopathic and regulatory T cells to create transplantation tolerance.

Therapeutic application of broadly reactive anti-T cell antibodies can lead not only to potent immunosuppression but also to profound and long-lived T cell depletion. We reasoned that a strategy that almost exclusively targets activated cytopathic donor reactive T cells and spares immunoregulatory networks might prove to be an exceptionally potent and highly selective means of producing long-term engraftment and tolerance. Herein we show that the combined administration of rapamycin and agonist IL-2- and antagonist IL-15-related cytolytic fusion proteins provides for long-term engraftment/tolerance in exceptionally stringent allotransplant models by (1) limiting the early expansion of activated T cells, (2) preserving and even exaggerating their subsequent apoptotic clearance, and (3) further amplifying the depletion of these activated T cells by antibody-dependent mechanisms, while (4) preserving CD4+CD25+ T cell-dependent immunoregulatory networks.

Proangiogenic function of CD40 ligand-CD40 interactions.

Angiogenesis is a characteristic component of cell-mediated immune inflammation. However, little is known of the immunologic mediators of angiogenesis factor production. Interactions between CD40 ligand (CD40L) and CD40 have been shown to have pluripotent functions in inflammation, including the production of cytokines, chemokines, as well as the angiogenesis factor, vascular endothelial growth factor (VEGF), by endothelial cells.

The role of the ICOS-B7h T cell costimulatory pathway in transplantation immunity.

Inducible costimulatory molecule (ICOS) plays a pivotal role in T cell activation and Th1/Th2 differentiation. ICOS blockade has disparate effects on immune responses depending on the timing of blockade. Its role in transplantation immunity, however, remains incompletely defined.

CD45RB-targeting strategies for promoting long-term allograft survival and preventingchronic allograft vasculopathy.

Background: CD45RB is a potent immunomodulatory target to achieve long-term allograft survival. We evaluated the in vivo effect of anti-CD45RB monoclonal antibody (mAb) treatment in combination with conventional immunosuppression or costimulatory blockade strategies as a therapeutic modality for future clinical application.

Methods: A fully MHC-mismatched vascularized mouse cardiac allograft model was used to test the interactions between anti-CD45RB mAb and conventional immunosuppressive drugs or costimulatory blockade of the CD40/CD154 or B7/CD28 pathway.

Allograft rejection in a new allospecific CD4+ TCR transgenic mouse.

The application of TCR transgenic mice to transplantation immunology is hampered by the limited lines available. Recently, we reported CD4+ T cell receptor (TCR) transgenic mice specific for I-Abm12 expressed on B6.C.

Clinical significance of aminopeptidase N/CD13 expression in human pancreatic carcinoma.

Purpose: We previously established a novel murine monoclonal antibody(MH8-11) that recognized aminopeptidase N (APN)/cluster of differentiation antigen 13 (CD13). This monoclonal antibody inhibited human umbilical vein endothelial cells migration and capillary-like tube formation of human umbilical vein endothelial cells on Matrigel. In this study, we investigated the expression of APN/CD13 and the intratumor microvessel density (IMD) as the number of microvessel counts in 50 patients with pancreatic carcinoma.

New insights into the interactions between T-cell costimulatory blockade and conventional immunosuppressive drugs.

Objective: To determine the precise in vivo interaction between T-cell costimulatory blockade and conventional immunosuppression in transplantation.

Summary Background Data: Blocking B7 or CD154 T-cell costimulatory activation pathways prevents allograft rejection in small and large animal transplant models and is considered a promising strategy for clinical organ transplantation.

Methods: A fully MHC-mismatched vascularized mouse cardiac allograft model was used to test the interactions between anti-CD154 or CTLA4Ig monotherapy and conventional immunosuppressive drugs in promoting long-term graft acceptance.

T-cell response to cardiac myosin persists in the absence of an alloimmune response in recipients with chronic cardiac allograft rejection.

Background: Immune-mediated injury to the graft has been implicated in the pathogenesis of chronic rejection. However, little is known regarding the nature of the antigen(s) involved in this immune process. We demonstrated that cardiac transplantation in mice induces an autoimmune T-cell response to a heart tissue-specific protein, cardiac myosin (CM).

Physiological mechanisms of regulating alloimmunity: cytokines, CTLA-4, CD25+ cells, and the alloreactive T cell clone size.

The mechanisms underlying physiological regulation of alloimmune responses remain poorly defined. We investigated the roles of cytokines, CTLA-4, CD25(+) T cells, and apoptosis in regulating alloimmune responses in vivo. Two murine cardiac transplant models were used, B10.