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We developed a method to generate dendritic cells (DCs) from mouse embryonic stem (ES) cells. We cultured ES cells for 10 days on feeder cell layers of OP9, in the presence of granulocyte-macrophage colony-stimulating factor in the latter 5 days. The resultant ES cell-derived cells were transferred to bacteriologic Petri dishes without feeder cells and further cultured. In about 7 days, irregularly shaped floating cells with protrusions appeared and these expressed major histocompatibility complex class II, CD11c, CD80, and CD86, with the capacity to stimulate primary mixed lymphocyte reaction (MLR) and to process and present protein antigen to T cells. We designated

Purpose: To establish cancer immunotherapy, it is important to identify the tumor-associated antigens (TAA) that are strongly expressed in the tumor cells but not in the normal cells. In this study, to establish an effective anticancer immunotherapy, we tried to identify the useful TAA of pancreatic cancer. Experimental Design: Based on a previous genome-wide cDNA microarray analysis of pancreatic cancer, we focused on cadherin 3 (CDH3)/P-cadherin as a novel candidateTAA for anticancer immunotherapy. To identify the HLA-A2 (A*0201)^restricted CTL epitopes of CDH3, we used HLA-A2.1 (HHD) transgenic mice (Tgm). Furthermore, we examined the cytotoxicity against the tumor cells in vitro and in vivo of CTLs specific to CDH3 induced from HLA-A2p ositive healthy donors and cancer patients. Results: CDH3 was overexpressed in the majority of pancreatic cancer and various other malignancies, including gastric and colorectal cancers, but not in their noncancerous counterparts or in many normal adult tissues. In the experiment using HLA-A2.1 Tgm, we found that the CDH3-4 655-663 (FILPVLGAV) and CDH3-7 757-765 (FIIENLKAA) peptides could induce HLA-A2^restricted CTLs inTgm. In addition, peptides-reactive CTLs were successfully induced from peripheral blood mononuclear cells by in vitro stimulation with these two peptides in HLAA2^positive healthy donors and cancer patients, and these CTLs exhibited cytotoxicity specific to cancer cells expressing both CDH3 and HLA-A2. Furthermore, the adoptive transfer of the CDH3-specific CTLs could inhibit the tumor growth of human cancer cells engrafted into nonobese diabetic/severe combined immunodeficiency mice. Conclusions: These results suggest that CDH3 is a novel TAA useful for immunotherapy against a broad spectrum of cancers, including pancreatic cancer.Pancreatic cancer has a poor prognosis, with an overall 5-year survival rate of f5% (1). A surgical resection remains the only option for a long-term survival, but patients with resectable pancreatic cancer are in the minority (9-22%; refs. 2 -4). Even in these patients, however, the 5-year survival rate remains f20% in spite of surgery with a curative intent (5, 6). Up to 80% of patients present with locally advanced or metastatic disease, and their median survival ranges from 6 to 9 months (7). It is generally thought that the presence of few signs or symptoms in the early stage, lack of an effective screening test, high rate of relapse, and poor response to current therapies contribute to the poor prognosis of this malignancy. Hence, the development of novel therapeutic modalities is an issue of great importance, and immunotherapy may be a potential treatment for pancreatic cancer.To establish an effective antitumor immunotherapy, the identification of tumor-associated antigens (TAA) plays a key role. In the past, many TAAs in various malignancies have been identified using the method of cDNA expression cloning (8 -10) and a serologic analysis of the recombinant cDNA expression library (11 -15). Recently, cDNA microarray...

Experimental autoimmune encephalomyelitis (EAE) is caused by activation of myelin Ag-reactive CD4+ T cells. In the current study, we tested a strategy to prevent EAE by pretreatment of mice with genetically modified dendritic cells (DC) presenting myelin oligodendrocyte glycoprotein (MOG) peptide in the context of MHC class II molecules and simultaneously expressing TRAIL or Programmed Death-1 ligand (PD-L1). For genetic modification of DC, we used a recently established method to generate DC from mouse embryonic stem cells (ES cells) in vitro (ES-DC). ES cells were sequentially transfected with an expression vector for TRAIL or PD-L1 and an MHC class II-associated invariant chain-based MOG epitope-presenting vector. Subsequently, double-transfectant ES cell clones were induced to differentiate to ES-DC, which expressed the products of introduced genes. Treatment of mice with either of the double-transfectant ES-DC significantly reduced T cell response to MOG, cell infiltration into spinal cord, and the severity of MOG peptide-induced EAE. In contrast, treatment with ES-DC expressing MOG alone, irrelevant Ag (OVA) plus TRAIL, or OVA plus PD-L1, or coinjection with ES-DC expressing MOG plus ES-DC-expressing TRAIL or PD-L1 had no effect in reducing the disease severity. In contrast, immune response to irrelevant exogenous Ag (keyhole limpet hemocyanin) was not impaired by treatment with any of the genetically modified ES-DC. The double-transfectant ES-DC presenting Ag and simultaneously expressing immune-suppressive molecules may well prove to be an effective therapy for autoimmune diseases without inhibition of the immune response to irrelevant Ag.

A protein containing a heme-binding PAS (PAS is from the protein names in which imperfect repeat sequences were first recognized: PER, ARNT, and SIM) domain from Escherichia coli has been implied a direct oxygen sensor (Ec DOS) enzyme. In the present study, we isolated cDNA for the Ec DOS full-length protein, expressed it in E. coli, and examined its structure-function relationships for the first time. Ec DOS was found to be tetrameric and was obtained as a 6-coordinate low spin ferric heme complex. Its ␣-helix content was calculated as 53% by CD spectroscopy. The redox potential of the heme was found to be ؉67 mV versus SHE. Mutation of His-77 of the isolated PAS domain abolished heme binding, whereas mutation of His-83 did not, suggesting that His-77 is one of the heme axial ligands. Ferrous, but not ferric, Ec DOS had phosphodiesterase (PDE) activity of nearly 0.15 min ؊1 with cAMP, which was optimal at pH 8.5 in the presence of Mg 2؉ and was strongly inhibited by CO, NO, and etazolate, a selective cAMP PDE inhibitor. Absorption spectral changes indicated tight CO and NO bindings to the ferrous heme. Therefore, the present study unequivocally indicates for the first time that Ec DOS exhibits PDE activity with cAMP and that this is regulated by the heme redox state.Heme proteins and enzymes perform a broad range of functions. Well known examples include O 2 storage with myoglobin, O 2 carriage with hemoglobin, mediators of electron transfer with cytochromes, and catalytic activation of heme ligands with P450s and peroxidases (1-3). Recently, a new class of heme enzymes involved in intramolecular signal transduction is emerging, known as heme-based sensors (4 -6). Almost of all the heme-based sensors contain two different functional domains as follows: one is an N-terminal heme domain, which acts a sensor, and the other is a catalytic domain such as a histidine kinase or a soluble guanylate cyclase. These heme sensor enzymes use the heme for mediating transcriptional and regulatory events associated with the presence of gaseous molecules such as CO, NO, and O 2 (4 -6). In these enzymes, the ligand association or dissociation from the heme iron leads to protein conformational changes, which transmit signals to the other domain where they initiate catalytic function or DNA binding. For example, the CooA 1 protein from Rhodospirillum rubrum is a CO sensor heme protein that regulates the expression of the coo genes associated with CO-dependent growth (Refs. 7 and 8 and references therein). Soluble guanylate cyclase is an NO sensor heme protein that regulates conversion of 5Ј-GTP to the intracellular second messenger, cGMP (Refs. 9 and 10 and references therein). Hem-AT-Bs and Hem-AT-Hs are oxygen sensors in which the hemes are thought to mediate signal transduction for methylation of the chemotaxis proteins (11, 12).The Fix proteins, FixL and FixJ, of Rhizobium meliloti are well characterized as biological oxygen sensors and regulate the expression of the nitrogen fixation genes of a plant symbiotic bacterium, Sino...

TRAIL is known to play a pivotal role in the inhibition of autoimmune disease. We previously demonstrated that administration of dendritic cells engineered to express TRAIL and myelin-oligodendrocyte glycoprotein reduced the severity of experimental autoimmune encephalomyelitis and suggested that CD4+CD25+ regulatory T cells (Tregs) were involved in mediating this preventive effect. In the current study, we investigated the effect of TRAIL on Tregs, as well as conventional T cells, using TRAIL-deficient mice. Upon induction of experimental autoimmune encephalomyelitis, TRAIL-deficient mice showed more severe clinical symptoms, a greater frequency of IFN-γ–producing CD4+ T (Th1) cells, and a lower frequency of CD4+Foxp3+ Tregs than did wild-type mice. In vitro, conventional T cells stimulated by bone marrow-derived dendritic cells (BM-DCs) from TRAIL-deficient mice showed a greater magnitude of proliferation than did those stimulated by BM-DCs from wild-type mice. In contrast, TRAIL expressed on the stimulator BM-DCs enhanced the proliferative response of CD4+CD25+ Tregs in the culture. The functional TRAILR, mouse death receptor 5 (mDR5), was expressed in conventional T cells and Tregs upon stimulation. In contrast, the decoy receptor, mDc-TRAILR1, was slightly expressed only on CD4+CD25+ Tregs. Therefore, the distinct effects of TRAIL may be due to differences in the mDc-TRAILR1 expression or the signaling pathways downstream of mouse death receptor 5 between the two T cell subsets. Our data suggest that TRAIL suppresses autoimmunity by two mechanisms: the inhibition of Th1 cells and the promotion of Tregs.

Toward the development of a novel cancer immunotherapy, we have previously identified several tumor-associated antigens (TAAs) and the epitopes recognized by human histocompatibility leukocyte (HLA)-A2/A24-restricted cytotoxic T lymphocyte (CTL). In this study, we tried to identify a TAA of lung cancer (LC) and its HLA-A2 restricted CTL epitopes to provide a target antigen useful for cancer immunotherapy of LC. We identified a novel cancer testis antigen, cell division cycle associated gene 1 (CDCA1), overexpressed in nonsmall cell LC using a cDNA microarray analysis. The expression levels of CDCA1 were also increased in the majority of small cell LC, cholangiocellular cancer, urinary bladder cancer and renal cell cancers. We used HLA-A2.1 transgenic mice to identify the HLA-A2 (A*0201)-restricted CDCA1 epitopes recognized by mouse CTL, and we investigated whether these peptides could induce CDCA1-reactive CTLs from the peripheral blood mononuclear cells (PBMCs) of HLA-A2-positive donors and a NSCLC patient. Consequently, we found that the CDCA1 65-73 (YMMPVNSEV) peptide and CDCA1 [351][352][353][354][355][356][357][358][359] (KLATAQFKI) peptide could induce peptide-reactive CTLs in HLA-A2.1 transgenic mice. In HLA-A2 1 donors, in vitro stimulation of PBMC with these peptides could induce peptide-reactive CTLs which killed tumor cell lines endogenously expressing both HLA-A2 and CDCA1. As a result, CDCA1 is a novel cancer-testis antigen overexpressed in LC, cholangiocellular cancer, urinary bladder cancer and renal cell cancers, and CDCA1 may therefore be an ideal TAA useful for the diagnosis and immunotherapy of these cancers.

Dendritic cell (DC)-based immunotherapy is regarded as a promising means for anti-cancer therapy. The efficiency of T cell-priming in vivo by transferred DCs should depend on their encounter with T cells. In the present study, we attempted to improve the capacity of DCs to prime T cells in vivo by genetic modification to express chemokine with a T cell-attracting property. For genetic modification of DCs, we used a recently established method to generate DCs from mouse embryonic stem cells. We generated double-transfectant DCs expressing a chemokine along with a model Ag (OVA) by sequential transfection of embryonic stem cells, and then induced differentiation to DCs. We comparatively evaluated the effect of three kinds of chemokines; secondary lymphoid tissue chemokine (SLC), monokine induced by IFN-γ (Mig), and lymphotactin (Lptn). All three types of double transfectant DCs primed OVA-specific CTLs in vivo more efficiently than did DCs expressing only OVA, and the coexpression of SLC or Lptn was more effective than that of Mig. Immunization with DCs expressing OVA plus SLC or Mig provided protection from OVA-expressing tumor cells more potently than did immunization with OVA alone, and SLC was more effective than Mig. In contrast, coexpression of Lptn gave no additive effect on protection from the tumor. Collectively, among the three chemokines, expression of SLC was the most effective in enhancing antitumor immunity by transferred DCs in vivo. The findings provide useful information for the development of a potent DC-based cellular immunotherapy.