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Tumor-associated Antigens (tumor-associated + antigen)
Selected AbstractsPeripheral tolerance limits CNS accumulation of CD8 T cells specific for an antigen shared by tumor cells and normal astrocytesGLIA, Issue 15 2008Thomas Calzascia Abstract T cell mediated immunotherapies are proposed for many cancers including malignant astrocytoma. As such therapies become more potent, but not necessarily more tumor-specific, the risk of collateral autoimmune damage to normal tissue increases. Tumors of the brain present significant challenges in this respect, as autoimmune destruction of brain tissue could have severe consequences. To investigate local immune reactivity toward a tumor-associated antigen in the brain, transgenic mice were generated that express a defined antigen (CW3170,179) in astroglial cells. The resulting six transgenic mouse lines expressed the transgenic self-antigen in cells of the gastrointestinal tract and CNS compartments, or in the CNS alone. By challenging transgenic mice with tumor cells that express CW3, self/tumor-specific immune responses were visualized within a normal polyclonal T cell repertoire. A large expansion of the endogenous CW3170,179 -specific CD8 T cell population was observed in nontransgenic mice after both subcutaneous and intracerebral implantation of tumor cells. In contrast, CW3170,179 -specific immune responses were not observed in transgenic mice that exhibited extracerebral transgene expression. Importantly, in certain groups of mice in which transgene expression was restricted to the CNS, antigen-specific immune responses occurred when tumor was implanted subcutaneously, but not intracerebrally. This local immune tolerance in the brain was induced via peripheral (extrathymic) rather than central (thymic) tolerance mechanisms. Thus, this study highlights the role of regional immune regulation in the prevention of autoimmunity in the brain, and the potential impact of these mechanisms for brain tumor immunotherapy. © 2008 Wiley-Liss, Inc. [source] The nuclear DNA repair protein Ku70/80 is a tumor-associated antigen displaying rapid receptor mediated endocytosisINTERNATIONAL JOURNAL OF CANCER, Issue 10 2006Johan Fransson Abstract To be of therapeutic relevance, a tumor-associated antigen should be expressed on the surface of neoplastic cells but not, or to a significantly lower extent, on cells of non-transformed nature. The Ku heterodimer (Ku70/80) is involved in DNA double strand break recognition and repair and is ubiquitously expressed in the nucleus of all cells. However, its exclusive nuclear localization has been reassessed by studies that demonstrate Ku to be expressed on the surface of tumor cell lines, displaying functions in cell adhesion, migration and invasion. In this study, we add another feature to the pluripotent role of Ku70/80 by showing that, upon binding the novel human recombinant antibody INCA-X, the Ku70/80 heterodimer is internalized into pancreatic carcinoma cells. The receptor-mediated endocytosis of Ku70/80 is rapid (t1/2 12 min) and extensive (90% of the receptor pool inside the cell after 100 min) as measured by rotating radioimmunoassay. Ku70/80 was also successfully used as a port of entry for cytotoxic payloads to tumor cells of various origin, as determined by indirect immunotoxin administration of a saporin-conjugated, secondary anti-human antibody. Thus, the internalization properties of the Ku70/80 suggest a potential role of this tumor associated antigen in selective drug-delivery in several human malignancies. © 2006 Wiley-Liss, Inc. [source] Identification of the H2-Kd -restricted cytotoxic T lymphocyte epitopes of a tumor-associated antigen, SPARC, which can stimulate antitumor immunity without causing autoimmune disease in miceCANCER SCIENCE, Issue 1 2009Yoshiaki Ikuta We previously reported that the secreted protein acidic and rich in cystein (SPARC) was overexpressed in melanoma in humans, and the serum SPARC level was useful as a novel tumor marker for melanoma. SPARC was also reported to be overexpressed in various human cancers. In this study, we asked whether SPARC-specific cytotoxic T lymphocytes (CTL) could induce antitumor immunity to SPARC-expressing tumor in mice or not as a preclinical study of SPARC-directed anticancer immunotherapy. Because of similarities in the structural motifs of major histocompatibility complex-binding peptides between H2-Kd and HLA-A24 (A*2402), the most common human leukocyte antigen class I allele in the Japanese population, we attempted to identify the H2-Kd -restricted SPARC epitope for CTL in BALB/c mice and we found that the mouse SPARC143,151 (DYIGPCKYI) and SPARC225,234 (MYIFPVHWQF) peptides could induce peptide-reactive CTL in BALB/c mice without causing autoimmune diseases. The immunization of mice with SPARC225,234 peptide-pulsed bone marrow-derived dendritic cells (BMDC) inhibited the growth of s.c. inoculated mouse mammary cancer cell line, N2C, expressing SPARC and these mice lived longer than the mice immunized with peptide-unpulsed BMDC. In conclusion, our study indicated that SPARC peptide-based cancer immunotherapy was effective and safe at least in a mouse tumor prevention model. (Cancer Sci 2009; 100: 132,137) [source] A recombinant bispecific single-chain antibody induces targeted, supra-agonistic CD28-stimulation and tumor cell killingEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2003Ludger Grosse-Hovest Abstract Endowing tumor cells with costimulatory signals for T cell activation has emerged as a promising strategy for tumor immunotherapy. Costimulatory molecules were either transfected into tumor cells to generate vaccines or were fused, e.g. to antibodies against tumor-associated antigens, to achieve targeted T cell costimulation in vivo. Here we report the production and purification of rM28, a recombinant bispecific single-chain antibody directed to a melanoma-associated proteoglycan and to the costimulatory CD28 molecule on human T cells. We found that a dimer of the recombinant molecule, bound to tumor target cells, induced pronounced T cell activation in peripheral blood mononuclear cell preparations without additional TCR/CD3 stimulation being required. Thelytic activity generated after 3,days of stimulation effectively prevented tumor cell growth. However, it was unspecific and predominantly mediated by non T cells. Our findings demonstrate that presentation of a CD28 antibody within a suitable recombinant, bispecific format may result in a "targeted supra-agonistic stimulation" of the CD28 molecule, which leads to effective tumor cell killing after induction of unspecifically lytic cells. [source] mRNA expression of tumor-associated antigens in melanoma tissues and cell linesEXPERIMENTAL DERMATOLOGY, Issue 4 2002Stefan Eichmüller Abstract: Tumor-associated antigens (TAA) are increasingly used as specific targets for immune therapy of malignant melanoma. The aim of the present study was to provide a basis for selecting the most suitable TAA by analyzing the mRNA expression of a large panel of TAA by RT-PCR and Northern blotting. We have chosen primers differentiating four groups of TAA (MAGE-A, MAGE-B, and two groups of GAGE-genes) and 13 individual TAA (MAGE-A2 and -A3, RAGE-1, -2, -3, and -4, LAGE-1a and -1b, NY-ESO-1, GAGE-1, SSX-2, SCP-1, and cTAGE-1) based on most recent sequence data. In addition, the RAGE-gene family has been separated into its four members by a novel designed nested PCR, which was confirmed by Northern analysis. Furthermore, the chromosomal organization and relationship between the RAGE-family and MOK was analyzed. RAGE-4 mRNA could be shown for the first time to be present in testis tissue. The most frequently expressed TAA were the MAGE-A and the GAGE-3,-4,-5,-6,-8 group, whereas among individual TAA MAGE-A2, -A3, RAGE-1, -3, and LAGE-1a/b were found within most specimens and are thus promising candidates for immune therapy. In comparison, melanoma metastatic specimens and cell lines show similar profiles of TAA expression, but individual TAA differ notably between both types of samples indicating that results from cell lines are not always applicable to tumor specimen. [source] Autoantibodies against stress-induced phosphoprotein-1 as a novel biomarker candidate for ovarian cancerGENES, CHROMOSOMES AND CANCER, Issue 7 2010Sunghoon Kim Detection of autoantibodies against tumor-associated antigens (TAA) has recently been shown to be a powerful tool for early detection of various cancers. The aim of this study was to investigate the possibility of using autoantibodies against TAA as novel biomarkers by a proteomics-based approach in patients with ovarian cancer. We used two-dimensional differential gel electrophoresis analysis of immuno-precipitated tumor antigens (2D-DITA) to compare the levels of autoandibodies in pretreatment and posttreatment sera of patients with ovarian cancers. The identified autoantibodies were validated by SYBR Green real-time polymerase chain reaction (PCR) and immunohistochemistry (IHC). We further evaluated the level of autoantibody in sera of 68 ovarian cancer patients by an enzyme-linked immunosorbent assay (ELISA). The autoantibody directed against stress-induced phosphoprotein-1 (STIP-1) emerged as a novel biomarker candidate for ovarian cancer. SYBR Green PCR and IHC confirmed that the STIP-1 mRNA and protein expression levels were significantly up-regulated in ovarian cancers compared with normal and benign tumors (P = 0.003 and P < 0.001, respectively). A preliminary ELISA study showed that the serum levels of anti-STIP-1 autoantibodies were significantly elevated in ovarian cancer patients compared with healthy controls (P = 0.03). The results suggest that 2D-DITA is a useful tool to detect autoantibodies and that STIP-1 is a potential biomarker candidate for ovarian cancers. © 2010 Wiley-Liss, Inc. [source] Identification of SPARC as a candidate target antigen for immunotherapy of various cancersINTERNATIONAL JOURNAL OF CANCER, Issue 6 2010Mitsuhiro Inoue Abstract 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-2Kd -restricted and SPARC-derived CTL epitope peptides in BALB/c mice, of which H-2Kd -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-A24-1143,151 (DYIGPCKYI) and SPARC-A24-4225,234 (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. [source] Phenotypic and functional characterization of mature dendritic cells from pediatric cancer patientsPEDIATRIC BLOOD & CANCER, Issue 7 2007Joannes F.M. Jacobs MD Abstract Background Dendritic cells (DCs) are the most potent antigen-presenting cells of the immune system. Clinical trials have demonstrated that mature DCs loaded with tumor-associated antigens can induce tumor-specific immune responses. Theoretically, pediatric patients are excellent candidates for immunotherapy since their immune system is more potent compared to adults. We studied whether sufficient amounts of mature monocyte-derived DCs can be cultured from peripheral blood of pediatric cancer patients. Procedure DCs from 15 pediatric patients with an untreated primary tumor were cultured from monocytes and matured with clinical grade cytokines. Phenotype and function were tested with flow cytometry, mixed lymphocyte reaction (MLR), and an in vitro migration assay. DCs of children with a solid tumor were compared with monocyte-derived DCs from age-related non-malignant controls. Results Ex vivo-generated monocyte-derived DCs from pediatric patients can be generated in numbers sufficient for DC vaccination trials. Upon cytokine stimulation the DCs highly upregulate the expression of the maturation markers CD80, CD83, and CD86. The mature DCs are six times more potent in inducing T cell proliferation compared to immature DCs. Furthermore, mature DCs, but not immature DCs, express the chemokine receptor CCR7 and have the capacity to migrate in vitro. Conclusions These data indicate that mature DCs can be generated ex vivo to further optimize DC-vaccination trials in pediatric cancer patients. Pediatr Blood Cancer 2007;49:924,927. © 2007 Wiley-Liss, Inc. [source] A different pattern of cytotoxic T lymphocyte recognition against primary and metastatic tumor cells in a patient with nonsmall cell lung carcinomaCANCER, Issue 1 2005Tetsuya So M.D. Abstract BACKGROUND Lung carcinoma represents the most frequent cause of cancer death worldwide because of tumor metastases. The objective of the current study was to analyze the immunologic response during the progress of lung carcinoma metastasis. METHODS The authors established two tumor cell lines that were derived from primary and metastatic lesions in a patient with lung carcinoma (Patient G603). One cell line (G603L) was established from the primary lesion, and the other cell line (G603AD) was established from a metastatic lesion in the right adrenal gland 7 months after the patient underwent surgery for the primary lesion. Autologous regional lymph node lymphocytes were stimulated with CD80-transfected G603L cells, then cytotoxic T lymphocytes (CTLs) were induced against both lung carcinoma cell lines. RESULTS Both G603L cells and G603AD cells expressed Class I human leukocyte antigen, intracellular cell adhesion molecule 1, and lymphocyte-associated antigen type 3 (LFA-3), but not Fas or Fas ligand on their surfaces. By stimulation with CD80-transfected G603L cells, 2 CTL clones (H2/17 and H2/36) were established from the bulk CTLs. CTL clone H2/17 lysed G603L cells but not G603AD cells, suggesting that the antigen recognized by CTL clone H2/17 was abrogated during the process of metastasis. In contrast, CTL clone H2/36 lysed both G603L cells and G603AD cells, indicating that the antigen recognized by CTL clone H2/36 was maintained in the tumor cells throughout tumor progression. CONCLUSIONS The results demonstrated the possibility that some tumor-associated antigens may be abrogated during the process of metastasis, although others are maintained. The identification of these antigens will lead to a better understanding of their immunologic role during disease progression in patients with lung carcinoma. Cancer 2005. © 2004 American Cancer Society. [source] Induction of carbohydrate-specific antibodies in HLA-DR transgenic mice by a synthetic glycopeptide: a potential anti cancer vaccine for human useCHEMICAL BIOLOGY & DRUG DESIGN, Issue 3 2003S. Vichier-Guerre Abstract: Over the last few years, anticancer immunotherapy has emerged as a new exciting area for controlling tumors. In particular, vaccination using synthetic tumor-associated antigens (TAA), such as carbohydrate antigens hold promise for generating a specific antitumor response by targeting the immune system to cancer cells. However, development of synthetic vaccines for human use is hampered by the extreme polymorphism of human leukocyte-associated antigens (HLA). In order to stimulate a T-cell dependent anticarbohydrate response, and to bypass the HLA polymorphism of the human population, we designed and synthesized a glycopeptide vaccine containing a cluster of a carbohydrate TAA B-cell epitope (Tn antigen: , -GalNAc-Ser) covalently linked to peptides corresponding to the Pan DR ,universal' T-helper epitope (PADRE) and to a cytotoxic T lymphocyte (CTL) epitope from the carcinoembryonic antigen (CEA). The immunogenicity of the construct was evaluated in outbred mice as well as in HLA transgenic mice (HLA-DR1, and HLA-DR4). A strong T-cell dependent antibody response specific for the Tn antigen was elicited in both outbred and HLA transgenic mice. The antibodies induced by the glycopeptide construct efficiently recognized a human tumor cell line underlying the biological relevance of the response. The rational design and synthesis of the glycopeptide construct presented herein, together with its efficacy to induce antibodies specific for native tumor carbohydrate antigens, demonstrate the potential of a such synthetic molecule as an anticancer vaccine candidate for human use. [source] | |||||||||||||