Possible Association of Mutations in the MEFV Gene with the Intestinal Phenotype of Behçet's Disease and Refractoriness to Treatment.

BACKGROUND: Mediterranean fever (MEFV) gene mutations are responsible for familial Mediterranean fever (FMF) and associated with other inflammatory diseases. However, the effects of MEFV gene mutations on intestinal Behçet's disease (BD) are unknown. In this study, we investigated these mutations and clinical features in patients with intestinal BD. METHODS: MEFV gene analysis was performed in 16 patients with intestinal BD, 10 with BD without intestinal lesions, and 50 healthy controls. Clinical features of patients with intestinal BD were retrospectively assessed. RESULTS: The rates of MEFV gene mutations in patients with intestinal BD, BD without intestinal lesions, and healthy controls were 75%, 50%, and 38%, respectively. Only 2 of 12 patients with intestinal BD harboring MEFV gene mutations (17%) were controlled without immunosuppressive treatment, while 8 patients (67%) required therapy with tumor necrosis factor (TNF) inhibitors. Among patients with intestinal BD without MEFV gene mutations (four patients), three (75%) were controlled by the administration of 5-aminosalicylic acid with or without colchicine, and one (25%) required TNF inhibitors. All patients who underwent intestinal resection had MEFV gene mutations. Immunohistochemical analysis and in situ hybridization with interleukin-1ß (IL-1ß) showed a high expression of IL-1ß only in injured areas, suggesting that IL-1ß may be involved in the formation of ulcers in patients with intestinal BD carrying MEFV gene mutations. CONCLUSION: Mutations in the MEFV gene may be associated with intestinal lesions of BD and refractoriness to treatment.

Single-incision laparoscopic ileocecal resection in a 10-year-old child with appendiceal neuroendocrine tumor.

BACKGROUND: In Japan, the majority of gastrointestinal tract neuroendocrine tumors (NETs) have been reported to originate from the rectum, and appendiceal NETs are relatively rare. Preoperative diagnosis is very difficult and it is diagnosed after appendectomy. Pediatric appendiceal NET is a disease with a good prognosis. However, in rare cases, lymph node metastasis could occur and additional resection is required. CASE PRESENTATION: A 10-year-old boy complained of right lower quadrant abdominal pain and underwent an appendectomy under a diagnosis of acute appendicitis in previous hospital. The final diagnosis was appendiceal NET, so he was referred to our department for additional resection. The tumor was found in the base of the appendix and invasively reached the subserosal layer with obvious vascular invasion. His Ki-67 index was 1 to 2%, so we classified it as appendiceal NET G1 according to the WHO 2015 classification. We considered the possibility of a tumor remnant or lymph node metastasis, so we performed single-incision laparoscopy with D3 lymph node dissection. The pathological diagnosis revealed no tumor remnant but metastasis to one lymph node. He was discharged on the 9th postoperative day. There has been no recurrence at 3 years and 7 months after surgery. CONCLUSION: When the tumor size is 10-20 mm, the frequency of lymph node metastasis in some reports is variable, and there is no consensus yet on the indications for additional resection. However, there are definitely a certain number of cases with lymph node metastasis that require additional resection. In the present patient, long-term survival can be obtained by additional resection. At present, factors such as the presence of vascular or lymph node invasion and the malignancy grade and tumor's location must be considered on a case-by-case basis. Although the incidence rate of appendiceal NET is rare, the diagnosis can be made only during postoperative pathological examination; thus, reliable histopathological examination is required.

Efficacy and Safety of Enoxaparin for Prophylaxis of Postoperative Venous Thromboembolism After Esophagectomy: A Single-center Prospective Randomized Controlled Phase II Study.

BACKGROUND/AIM: This study aimed to assess whether low-molecular-weight heparin (LMWH) is effective and safe in preventing postoperative venous thromboembolism (VTE) in patients undergoing esophageal cancer surgery. PATIENTS AND METHODS: In this single-institution, prospective, randomized trial, 73 patients with esophageal cancer undergoing esophagectomy were randomly divided into the enoxaparin group (E group) and intermittent pneumatic compression group (I group). The primary endpoint was efficacy of enoxaparin, and secondary endpoints were evidence of bleeding and serum anti-Xa activity in the E group. RESULTS: The E group comprised 42 patients and the I group comprised 31 patients. Deep vein thrombosis was observed in 0 (0%) patients in the E group and 7 (22.6%) patients in the I group (p=0.002). Soluble fibrin monomer complex was significantly lower in the E versus I group on day 8 (p<0.001). D-dimer was significantly lower in the E versus I group on days 2, 8, and 15 (p=0.008, p<0.001, p<0.001, respectively). CONCLUSION: VTE was significantly reduced by using enoxaparin.

A xenograft model reveals that PU.1 functions as a tumor suppressor for multiple myeloma in vivo.

We previously demonstrated that PU.1 expression is down-regulated in the majority of myeloma cell lines and primary myeloma cells from patients. We introduced the tet-off system into the human myeloma cell lines U266 and KMS12PE that conditionally express PU.1 and demonstrated that PU.1 induces cell cycle arrest and apoptosis in myeloma cells in vitro. Here, we established a mouse xenograft model of myeloma using these cell lines to analyze the effects of PU.1 on the phenotype of myeloma cells in vivo. When doxycycline was added to the drinking water of mice engrafted with these myeloma cells, all mice had continuous growth of subcutaneous tumors and could not survived more than 65 days. In contrast, mice that were not exposed to doxycycline did not develop subcutaneous tumors and survived for at least 100 days. We next generated mice engrafted with subcutaneous tumors 5-10 mm in diameter that were induced by exposure to doxycycline. Half of the mice stopped taking doxycycline-containing water, whereas the other half kept taking the water. Although the tumors in the mice taking doxycycline continued to grow, tumor growth in the mice not taking doxycycline was significantly suppressed. The myeloma cells in the tumors of the mice not taking doxycycline expressed PU.1 and TRAIL and many of such cells were apoptotic. Moreover, the expression of a cell proliferation marker Ki67 was significantly decreased in tumors from the mice not taking doxycycline, compared with that of tumors from the mice continuously taking doxycycline. The present data strongly suggest that PU.1 functions as a tumor suppressor of myeloma cells in vivo.

[A Case Report of Neuroendocrine Carcinoma of the Esophagus Treated with Multidisciplinary Therapy].

A 72-year-old man was referred to our department because of esophageal tumor. Immunohistochemical findings were CD56-positive, synaptophysin-positive, chromogranin A-positive, Ki-67(labeling index)≥90%. The diagnosis was esophageal neuroendocrine carcinoma, categorized as cT4b(106recR-main bronchus), cN1(106recR), cM0, cStage III C. We had initiated irinotecan plus cisplatin(IP)as neoadjuvant chemotherapy(NAC). Biopsy specimens of primary lesion after 1 course chemotherapy showed a change to squamous cell carcinoma(SCC). The target lesion exhibited partial response(PR)after 2 courses of chemotherapy, and the primary lesion was reduced, but was still present. We performed subtotal esophagectomy and subtotal stomach reconstruction with lymphadenectomy(R0, Cur A). The histopathological findings showed the primary lesion was SCC, metastatic lymph nodes(106recR)was NEC. The final diagnosis was SCC plus NEC, categorized as CT-pT1a (MM), pN1(106recR), M0, fStage II B. After that, we selected treatment regimen considering tissue type, and performed surgery and chemotherapy for 2 times of recurrences. At a follow-up examination 1 year and 2 months after the start of first chemotherapy, the patient is alive without recurrence. Esophageal neuroendocrine carcinoma is relatively rare and the prognosis is poor, but there is as yet no standard therapy. We experienced a case of neuroendocrine carcinoma of the esophagus treated with multidisciplinary therapy.

Angiotensin II type 1 receptor blocker telmisartan induces apoptosis and autophagy in adult T-cell leukemia cells.

Adult T-cell leukemia/lymphoma (ATL), an aggressive T-cell malignancy that develops after long-term infection with human T-cell leukemia virus (HTLV-1), requires new treatments. Drug repositioning, reuse of a drug previously approved for the treatment of another condition to treat ATL, offers the possibility of reduced time and risk. Among clinically available angiotensin II receptor blockers, telmisartan is well known for its unique ability to activate peroxisome proliferator-activated receptor-γ, which plays various roles in lipid metabolism, cellular differentiation, and apoptosis. Here, telmisartan reduced cell viability and enhanced apoptotic cells via caspase activation in ex vivo peripheral blood monocytes from asymptomatic HTLV-1 carriers (ACs) or via caspase-independent cell death in acute-type ATL, which has a poor prognosis. Telmisartan also induced significant growth inhibition and apoptosis in leukemia cell lines via caspase activation, whereas other angiotensin II receptor blockers did not induce cell death. Interestingly, telmisartan increased the LC3-II-enriched protein fraction, indicating autophagosome accumulation and autophagy. Thus, telmisartan simultaneously caused caspase activation and autophagy. A hypertension medication with antiproliferation effects on primary and leukemia cells is intriguing. Patients with an early diagnosis of ATL are generally monitored until the disease progresses; thus, suppression of progression from AC and indolent ATL to acute ATL is important. Our results suggest that telmisartan is highly effective against primary cells and leukemia cell lines in caspase-dependent and -independent manners, and its clinical use may suppress acute transformation and improve prognosis of patients with this mortal disease. This is the first report demonstrating a cell growth-inhibitory effect of telmisartan in fresh peripheral blood mononuclear cells from leukemia patients.

Immunomodulatory drugs act as inhibitors of DNA methyltransferases and induce PU.1 up-regulation in myeloma cells.

Immunomodulatory drugs (IMiDs) such as thalidomide, lenalidomide, and pomalidomide are efficacious in the treatment of multiple myeloma and significantly prolong their survival. However, the mechanisms of such effects of IMiDs have not been fully elucidated. Recently, cereblon has been identified as a target binding protein of thalidomide. Lenalidomide-resistant myeloma cell lines often lose the expression of cereblon, suggesting that IMiDs act as an anti-myeloma agent through interacting with cereblon. Cereblon binds to damaged DNA-binding protein and functions as a ubiquitin ligase, inducing degradation of IKZF1 and IKZF3 that are essential transcription factors for B and T cell development. Degradation of both IKZF1 and IKZF3 reportedly suppresses myeloma cell growth. Here, we found that IMiDs act as inhibitors of DNA methyltransferases (DMNTs). We previously reported that PU.1, which is an ETS family transcription factor and essential for myeloid and lymphoid development, functions as a tumor suppressor in myeloma cells. PU.1 induces growth arrest and apoptosis of myeloma cell lines. In this study, we found that low-dose lenalidomide and pomalidomide up-regulate PU.1 expression through inducing demethylation of the PU.1 promoter. In addition, IMiDs inhibited DNMT1, DNMT3a, and DNMT3b activities in vitro. Furthermore, lenalidomide and pomalidomide decreased the methylation status of the whole genome in myeloma cells. Collectively, IMiDs exert demethylation activity through inhibiting DNMT1, 3a, and 3b, and up-regulating PU.1 expression, which may be one of the mechanisms of the anti-myeloma activity of IMiDs.

Rituximab Monotherapy and Rituximab-Containing Chemotherapy Were Effective for Paraneoplastic Pemphigus Accompanying Follicular Lymphoma, but not for Subsequent Bronchiolitis Obliterans.

A 60-year-old male patient suffered from mild exertional dyspnea, wheezing, and systemic blisters. He was diagnosed with paraneoplastic pemphigus (PNP) with follicular lymphoma in the pancreas head and pelvic cavity. He was first treated with eight cycles of rituximab; his blisters and erosions gradually improved and highly elevated levels of auto-antibodies related to PNP gradually decreased to normal levels. However, obstructive and restrictive respiratory failure still progressed. Computed tomography of the inspiratory and expiratory phases revealed obstructive pulmonary disorder, leading to a diagnosis of bronchiolitis obliterans (BO). The patient underwent plasma exchange and was repeatedly treated with rituximab monotherapy and rituximab-containing chemotherapies, but died 7 months after the diagnosis of BO. Early introduction of rituximab-containing regimens may be necessary to prevent the development of BO accompanying PNP. However, when a diagnosis of PNP-related BO is made, lung transplantation may also be considered for patients in whom rituximab-containing regimens are effective for PNP.

Injury and subsequent regeneration of muscles for activation of local innate immunity to facilitate the development and relapse of autoimmune myositis in C57BL/6 mice.

OBJECTIVE: To determine whether injury and regeneration of the skeletal muscles induce an inflammatory milieu that facilitates the development and relapse of autoimmune myositis. METHODS: The quadriceps of C57BL/6 mice were injured with bupivacaine hydrochloride (BPVC) and evaluated histologically. Macrophages and regenerating myofibers in the treated muscles and differentiating C2C12 myotubes were examined for cytokine expression. Mice were immunized with C protein fragments at the base of the tail and in the right hind footpads (day 0) to evoke systemic anti-C protein immunity and to induce local myositis in the right hind limbs. The contralateral quadriceps muscles were injured with BPVC or phosphate buffered saline (PBS) on day 7 or after spontaneous regression of myositis (day 42). The quadriceps muscle in nonimmunized mice was injured with BPVC on day 7. The muscles were examined histologically 14 days after treatment. RESULTS: The BPVC-injured muscles had macrophage infiltration most abundantly at 3 days after the injection, with emergence of regenerating fibers from day 5. The macrophages expressed inflammatory cytokines, including tumor necrosis factor α, interleukin-1ß, and CCL2. Regenerating myofibers and C2C12 myotubes also expressed the cytokines. The BPVC-injected muscles from nonimmunized mice had regenerating myofibers with resolved cell infiltration 14 days after treatment. In mice preimmunized with C protein fragments, the muscles injected with BPVC on day 7 as well as on day 42, but not those injected with PBS, had myositis accompanied by CD8+ T cell infiltration. CONCLUSION: Injury and regeneration could set up an inflammatory milieu in the muscles and facilitate the development and relapse of autoimmune myositis.

Experimental myositis inducible with transfer of dendritic cells presenting a skeletal muscle C protein-derived CD8 epitope peptide.

It is suggested that polymyositis, an autoimmune inflammatory myopathy, is mediated by autoaggressive CD8 T cells. Skeletal muscle C protein is a self-antigen that induces C protein-induced myositis, a murine model of polymyositis. To establish a new murine model of myositis inducible with a single CD8 T-cell epitope peptide that derives from the C protein, three internet-based prediction systems were employed to identify 24 candidate peptides of the immunogenic fragment of the C protein and bind theoretically to major histocompatibility complex class I molecules of C57BL/6 (B6) mice. RMA-S cell assay revealed that a HILIYSDV peptide, amino acid position 399-406 of the C protein, had the highest affinity to the H2-K(b) molecules. Transfer of mature bone marrow-derived dendritic cells pulsed with HILIYSDV induced myositis in naive B6 mice. This myositis was suppressed by anti-CD8-depleting antibodies but not by anti-CD4-depleting antibodies. Because this myositis model is mediated by CD8 T cells independently of CD4 T cells, it should be a useful tool to investigate pathology of polymyositis and develop therapies targeting CD8 T cells.

Abatacept may be effective and safe in patients with amyloid A amyloidosis secondary to rheumatoid arthritis.

OBJECTIVES: To examine the efficacy and safety of abatacept (ABT) in patients with amyloid A (AA) amyloidosis secondary to rheumatoid arthritis (RA), and to speculate about the immunologic association of ABT with AA amyloid deposit regression. METHODS: We administered ABT to 70- and 65-year-old Japanese women with RA and AA amyloidosis. We quantified serum cytokine concentrations and analysed regulatory T lymphocytes (Treg cells) via flow cytometry. We also studied AA amyloid deposits via histopathology and immunohistochemistry. RESULTS: ABT improved rheumatoid inflammation and AA amyloidosis, one case showing clinical remission and the other demonstrating incomplete recovery of nephrosis but stable kidney function. Serum levels of interleukin-6 and tumour necrosis factor α decreased to baseline in the first 6 months of treatment, but serum interleukin-2 concentrations did not change. CD4+CD25++FoxP3+ Treg cells gated on T lymphocytes and CD4+ T lymphocytes decreased to baseline in the first 3 treatment months. One case showed complete regression of AA amyloid fibrils in serial upper gastrointestinal biopsies, but the other case still had AA amyloid deposits despite ABT-induced normalised rheumatoid inflammation, with polymorphonuclear leukocytes and macrophages infiltrating tissues containing AA amyloid. CONCLUSIONS: ABT demonstrated efficacy and safety in AA amyloidosis secondary to RA and affected Treg cells and inflammatory cytokines. Because the gradual decrease in Treg cells population coincided with AA amyloid deposit regression during ABT therapy, AA amyloid fibril turnover in these patients may involve an immunologic mechanism. Phagocytes seemed to have an important role in AA amyloid fibril regression, which suggests an immunologic interaction.

Immunotherapy with pluripotent stem cell-derived dendritic cells.

In vivo transfer of dendritic cells (DC) has proven efficient in the priming of T cells and is regarded as a powerful means of providing anti-cancer immunotherapy. Clinical trials of anti-cancer therapy with DC pulsed with peptide antigens have been carried out in many institutions, although dramatic therapeutic effect has not been observed in most of the trials. Negative regulation of the immune response by DC might be applicable to treatment of autoimmune diseases and transplantation medicine. Currently, the DC used for anti-cancer vaccine therapy are generated from the peripheral blood monocytes of the patients. However, there is a limitation in the number of available monocytes and the potential of monocytes to differentiate into DC varies depending on the individual blood donors. To resolve the issue of the cell source for DC therapy, several groups have developed methods to generate DC from pluripotent stem cells. This review introduces methods to generate functional DC from pluripotent stem cells of mouse and human.

Oligomannose-coated liposomes efficiently induce human T-cell leukemia virus-1-specific cytotoxic T lymphocytes without adjuvant.

Human T-cell leukemia virus-1 (HTLV-1) causes adult T-cell leukemia/lymphoma, which is an aggressive peripheral T-cell neoplasm. Insufficient T-cell response to HTLV-1 is a potential risk factor in adult T-cell leukemia/lymphoma. Efficient induction of antigen-specific cytotoxic T lymphocytes is important for immunological suppression of virus-infected cell proliferation and oncogenesis, but efficient induction of antigen-specific cytotoxic T lymphocytes has evaded strategies utilizing poorly immunogenic free synthetic peptides. Here, we examined the efficient induction of an HTLV-1-specific CD8+ T-cell response by oligomannose-coated liposomes (OMLs) encapsulating the human leukocyte antigen (HLA)-A*0201-restricted HTLV-1 Tax-epitope (OML/Tax). Immunization of HLA-A*0201 transgenic mice with OML/Tax induced an HTLV-1-specific gamma-interferon reaction, whereas immunization with epitope peptide alone induced no reaction. Upon exposure of dendritic cells to OML/Tax, the levels of CD86, major histocompatibility complex class I, HLA-A02 and major histocompatibility complex class II expression were increased. In addition, our results showed that HTLV-1-specific CD8+ T cells can be efficiently induced by OML/Tax from HTLV-1 carriers compared with epitope peptide alone, and these HTLV-1-specific CD8+ T cells were able to lyse cells presenting the peptide. These results suggest that OML/Tax is capable of inducing antigen-specific cellular immune responses without adjuvants and may be useful as an effective vaccine carrier for prophylaxis in tumors and infectious diseases by substituting the epitope peptide.

Peptides derived from human insulin-like growth factor-II mRNA binding protein 3 can induce human leukocyte antigen-A2-restricted cytotoxic T lymphocytes reactive to cancer cells.

Insulin-like growth factor-II mRNA binding protein 3 (IMP-3) is an oncofetal protein expressed in various malignancies including lung cancer. This study aimed to identify immunogenic peptides derived from IMP-3 that can induce tumor-reactive and human leukocyte antigen (HLA)-A2 (A*02:01)-restricted cytotoxic T lymphocytes (CTL) for lung cancer immunotherapy. Forty human IMP-3-derived peptides predicted to bind to HLA-A2 were analyzed to determine their capacity to induce HLA-A2-restricted T cells in HLA-A2.1 (HHD) transgenic mice (Tgm). We found that three IMP-3 peptides primed HLA-A2-restricted CTL in the HLA-A2.1 Tgm. Among them, human CTL lines reactive to IMP-3 (515) NLSSAEVVV(523) were reproducibly established from HLA-A2-positive healthy donors and lung cancer patients. On the other hand, IMP-3 (199) RLLVPTQFV(207) reproducibly induced IMP-3-specific and HLA-A2-restricted CTL from healthy donors, but did not sensitize CTL in the HLA-A2.1 Tgm. Importantly, these two IMP-3 peptide-specific CTL generated from healthy donors and cancer patients effectively killed the cancer cells naturally expressing both IMP-3 and HLA-A2. Cytotoxicity was significantly inhibited by anti-HLA class I and anti-HLA-A2 monoclonal antibodies, but not by the anti-HLA-class II monoclonal antibody. In addition, natural processing of these two epitopes derived from the IMP-3 protein was confirmed by specific killing of HLA-A2-positive IMP-3-transfectants but not the parental IMP-negative cell line by peptide-induced CTL. This suggests that these two IMP-3-derived peptides represent highly immunogenic CTL epitopes that may be attractive targets for lung cancer immunotherapy.

Dual effects of TRAIL in suppression of autoimmunity: the inhibition of Th1 cells and the promotion of regulatory T cells.

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.

Pluripotent stem cell-derived dendritic cells for immunotherapy.

Dendritic cell (DC) is regarded as a powerful means for anti-cancer immunotherapy. Clinical trials of cancer therapy with DC loaded with cancer antigens, such as tumor cell-lysates or HLA class I-binding antigenic peptides, have been conducted. Antigen-specific negative manipulation of the immune response by DC is a potential treatment for autoimmune diseases and also for control of allo-reactive immune responses in transplantation medicine. Currently, DC for clinical use are generated from peripheral blood monocytes of the patients. However, the number of monocytes obtained from the patients is limited and the potential of monocytes to differentiate into DC varies depending on the blood donor. Thus, the issue of limited cells is a serious obstacle for DC therapy. ES cells and iPS cells have pluripotency and unlimited propagation capacity and may be an ideal cell source for DC-therapy. Several groups, including us, have developed methods to generate DC from ES cells or iPS cells. This review introduces the studies on generation, characterization, and genetic modification of DC derived from ES cells or iPS cells.

Pluripotent stem cells as source of dendritic cells for immune therapy.

Dendritic cells (DC) are the most potent antigen-presenting cells. In vivo transfer of antigen-bearing DC has proven efficient in priming T cell responses specific to the antigen. DC-based cellular vaccination is now regarded as a powerful means for immunotherapy, especially for anti-cancer immunotherapy. Clinical trials of therapy with DC pulsed with peptide antigens or genetically modified to present antigens are currently carried out in many institutions. In addition, antigen-specific negative regulation of immune response by DC is considered to be a promising approach for treatments of autoimmune diseases and also for regulation of allo-reactive immune response causing graft rejection and GVHD in transplantation medicine. DC for transfer therapy are now generated by in vitro differentiation of peripheral blood monocytes of the patients. However, there is a limitation in the number of available monocytes, and the DC-differentiation potential of monocytes varies depending on the blood donor. Embryonic stem (ES) cells possess both pluripotency and infinite propagation capacity. We consider ES cells to be an ideal source for DC to be used in immunotherapy. Several groups, including us, have developed methods to generate DC from ES cells. This review introduces the studies on generation, characterization, and genetic modification of DC derived from ES cells or induced pluripotent stem (iPS) cells. The issues to be resolved before clinical application of pluripotent stem cell-derived DC will also be discussed.

Identification of SPARC as a candidate target antigen for immunotherapy of various cancers.

To establish efficient anticancer immunotherary, it is important to identify tumor-associated antigens (TAAs) directing the immune system to attack cancer. A genome-wide cDNA microarray analysis identified that secreted protein acidic and rich in cysteine (SPARC) gene is overexpressed in the gastric, pancreatic and colorectal cancer tissues but not in their noncancerous counterparts. This study attempted to identify HLA-A24 (A*2402)-restricted and SPARC-derived CTL epitopes. We previously identified H-2K(d)-restricted and SPARC-derived CTL epitope peptides in BALB/c mice, of which H-2K(d)-binding peptide motif is comparable with that of HLA-A24 binding peptides. By using these peptides, we tried to induce HLA-A24 (A*2402)-restricted and SPARC-reactive human CTLs and demonstrated an antitumor immune response. The SPARC-A24-1(143-151) (DYIGPCKYI) and SPARC-A24-4(225-234) (MYIFPVHWQF) peptides-reactive CTLs were successfully induced from peripheral blood mononuclear cells by in vitro stimulation with these two peptides in HLA-A24 (A*2402) positive healthy donors and cancer patients, and these CTLs exhibited cytotoxicity specific to cancer cells expressing both SPARC and HLA-A24 (A*2402). Furthermore, the adoptive transfer of the SPARC-specific CTLs could inhibit the tumor growth in nonobese diabetic/severe combined immunodeficient mice bearing human cancer cells expressing both HLA-A24 (A*2402) and SPARC. These findings suggest that SPARC is a potentially useful target candidate for cancer immunotherapy.