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ABSTRACT: Effective immunotherapy using T cell receptor (TCR) gene-modified T cells requires an understanding of the relationship between
TCR affinity and functional avidity of T cells. In this study, we evaluate the relative affinity of two TCRs isolated from
HLA-A2-restricted, gp100-reactive T cell clones with extremely high functional avidity. Furthermore, one of these T cell clones,
was CD4−CD8− indicating that antigen recognition by this clone was CD8 independent. However, when these TCRs were expressed in CD8− Jurkat cells, the resulting Jurkat cells recognized gp100:209–217 peptide loaded T2 cells and had high functional avidity,
but could not recognize HLA-A2+ melanoma cells expressing gp100. Tumor cell recognition by Jurkat cells expressing these TCRs could not be induced by exogenously
loading the tumor cells with the native gp100:209–217 peptide. These results indicate that functional avidity of a T cell
does not necessarily correlate with TCR affinity and CD8-independent antigen recognition by a T cell does not always mean
its TCR will transfer CD8-independence to other effector cells. The implications of these findings are that T cells can modulate
their functional avidity independent of the affinity of their TCRs.
Cancer Immunology and Immunotherapy 04/2012; 58(5):719-728. · 3.70 Impact Factor
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ABSTRACT: About a century ago Otto Warburg observed that tumor cells exhibited increased glycolysis despite the presence of oxygen and stated this metabolic shift to glycolysis as the origin of cancer cell. In the meantime it has become clear, that the altered glucose metabolism is only one piece of the tumor metabolome puzzle. In addition, amino acid, lipid and adenosine metabolism are adapted to fulfill the tumors needs for energy and generation of building blocks such as lipids and nucleotides for new cell structures. The altered tumor metabolism leads to accumulation of specific metabolites in the tumor environment and creates a favorable milieu for tumor growth, progression and metastasis. These tumor-derived metabolites are important players in immune escape mechanisms beside other known factors such as cytokines, chemokines and growth factors. A variety of metabolites re-educate immune cells and prevent an effective immune response against tumor cells. Furthermore, tumor infiltrating immune cells support tumor growth by the secretion of cytokines, growth factors and other metabolic determinants. Hence, a complex interplay of tumor metabolites, cytokines and stromal factors is active in tumors and facilitates their establishment and growth. Pharmacological blockade of tumor metabolites could overcome some limitations of cancer treatment and rescue the endogenous immune response against tumor cells.
Seminars in Cancer Biology 03/2012; 22(4):335-41. · 6.47 Impact Factor
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Onkologie 01/2012; 35 Suppl 2:1. · 0.87 Impact Factor
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ABSTRACT: Upon specific interaction with APCs, T cells capture membrane fragments and surface molecules in a process termed trogocytosis. In this study, we demonstrate that human Ag-specific CD8(+) T cells acquire the coinhibitory molecule programmed death ligand 1 (PD-L1) from mature dendritic cells (mDC) and tumor cells in an Ag-specific manner. Immature dendritic cells were less effective in transferring surface molecules onto CD8(+) T cells than mDCs. Interestingly, trogocytosis of PD-L1 requires cell-cell contact and cannot be induced by uptake of soluble proteins obtained from mDC lysates. The transfer process is impaired by inhibition of vacuolar ATPases in T cells as well as by fixation of dendritic cells. Of importance, CD8(+) T cells that acquired PD-L1 complexes were able to induce apoptosis of neighboring programmed death 1-expressing CD8(+) T cells. In summary, our data demonstrate that human CD8(+) T cells take up functionally active PD-L1 from APCs in an Ag-specific fashion, leading to fratricide of programmed death 1-expressing, neighboring T cells. The transfer of functionally active coinhibitory molecules from APCs onto human CD8(+) T cells could have a regulatory role in immune responses.
The Journal of Immunology 12/2011; 188(2):744-52. · 5.79 Impact Factor
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Katrin Singer,
Michael Kastenberger,
Eva Gottfried,
Christine G Hammerschmied,
Maike Büttner,
Michael Aigner,
Barbara Seliger,
Bernhard Walter,
Hans Schlösser,
Arndt Hartmann,
Reinhard Andreesen, Andreas Mackensen,
Marina Kreutz
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ABSTRACT: Many tumor cells are characterized by a dysregulated glucose metabolism associated with increased glycolysis in the presence of oxygen ("Warburg Effect"). Here, we analyzed for the first time a possible link between glucose metabolism and immune cell infiltration in renal cell carcinoma (RCC). RCC specimens revealed a highly significant increase in the expression of lactate dehydrogenase A (LDHA) and glucose-transporter 1 (GLUT-1) compared to the corresponding normal kidney tissue on mRNA level. Accordingly, tumor cell lines of different origin such as RCC, melanoma and hepatocellular carcinoma strongly expressed LDHA and GLUT-1 compared to their nonmalignant counterparts. In line with this finding, tumor cells secreted high amounts of lactate. High expression of GLUT-1 and LDH5, a tetramer of 4 LDHA subunits, was confirmed by tissue microarray analysis of 249 RCC specimens. Overall, 55/79 (69.6%) and 46/71 (64.7%) cases of clear cell carcinoma showed a constitutive, but heterogeneous expression of GLUT-1 and LDH5, respectively. The number of CD3(+), CD8(+) and FOXP3(+) T cells was significantly elevated in RCC lesions compared to normal kidney epithelium, but effector molecules such as granzyme B and perforin were decreased in tumor infiltrating T cells. Of interest, further analysis revealed an inverse correlation between GLUT-1 expression and the number of CD8(+) T cells in RCC lesions. Together, our data suggest that an accelerated glucose metabolism in RCC tissue is associated with a low infiltration of CD8(+) effector T cells. Targeting the glucose metabolism may represent an interesting tool to improve the efficacy of specific immunotherapeutic approaches in RCC.
International Journal of Cancer 05/2011; 128(9):2085-95. · 5.44 Impact Factor
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ABSTRACT: Regulatory T cells (Tregs) play an important role in the maintenance of immune tolerance to self-antigens and are involved in modulating immune responses in autoimmunity, transplant rejection, and tumor immunity. Recently, a novel subset of TCR-αβ(+) CD4(-) CD8(-) (double negative, DN) T cells has been described to specifically suppress T-cell responses in mice. Here, we demonstrate that human DN T cells are highly potent suppressors of both CD4(+) and CD8(+) T-cell responses. In contrast to naturally occurring CD4(+) CD25(+) Tregs, DN T cells have to be activated by antigen-presenting cells (APCs) to induce their regulatory potential. The suppressive activity of DN T cells is neither mediated indirectly by modulation of APCs nor by competition for T-cell growth factors. Furthermore, DN T-cell-mediated suppression toward responder T cells is TCR dependent and requires novel protein synthesis. In contrast to murine DN T cells, which eliminate effector T cells via Fas/FasL or perforin/granzyme, human DN T cells suppress proliferation of responder T cells by cell contact-dependent mechanisms. Taken together, our data indicate that human DN T cells exert strong immunosuppressive effects on both CD4(+) and CD8(+) T cells and may serve as a new therapeutic approach to treat autoimmunity and transplant rejection.
European Journal of Immunology 03/2011; 41(3):739-48. · 5.10 Impact Factor
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ABSTRACT: Tumor cells have developed multiple mechanisms to escape T-cell-mediated immune recognition. Recent work has revealed that the altered tumor metabolism depletes essential nutrients or leads to the accumulation of immunosuppressive metabolites in the tumor microenvironment. In this review, we discuss the suppressive activity of some metabolic key players, which are upregulated in human tumor cells, including indolamine-2,3-dioxygenase (IDO), arginase, inducible nitric oxide synthetase (iNOS), and lactate dehydrogenase (LDH)-A, on the adaptive immune system. A better understanding of the impact of metabolic alterations of tumor cells on effector T-cell functions could lead to new therapeutic strategies to improve the efficacy of cancer immunotherapy.
Cancer Immunology and Immunotherapy 03/2011; 60(3):425-31. · 3.70 Impact Factor
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Onkologie 01/2011; 34 Suppl 2:1. · 0.87 Impact Factor
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ABSTRACT: At present, the treatment of T-cell-dependent autoimmune diseases relies exclusively on strategies leading to nonspecific suppression of the immune systems causing a substantial reduced ability to control concomitant infections or malignancies. Furthermore, long-term treatment with most drugs is accompanied by several serious adverse effects and does not consequently result in cure of the primary immunological malfunction. By contrast, antigen-specific immunotherapy offers the potential to achieve the highest therapeutic efficiency in accordance with minimal adverse effects. Therefore, several studies have been performed utilizing antigen-presenting cells specifically engineered to deplete allo- or antigen-specific T cells ('guided missiles'). Many of these strategies take advantage of the Fas/Fas ligand signaling pathway to efficiently induce antigen-presenting cell-mediated apoptosis in targeted T cells. In this article, we discuss the advantages and shortcomings of a novel non-cell-based 'killer artificial antigen-presenting cell' strategy, developed to overcome obstacles related to current cell-based approaches for the treatment of T-cell-mediated autoimmunity.
Immunotherapy 07/2010; 2(4):539-50. · 1.85 Impact Factor
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ABSTRACT: Adoptive cell transfer (ACT), either using rapidly expanded tumor infiltrating lymphocytes or T-cell receptor transduced peripheral blood lymphocytes, can be considered one of the most promising approaches in cancer immunotherapy. ACT results in the repopulation of the host with high frequencies of tumor-specific T cells; however, optimal function of these cells within the tumor micro-environment is required to reach long-term tumor clearance. We and others have shown that ongoing anti-tumor immune responses can be impaired by the expression of ligands, such as PD-L1 (B7-H1) on tumor cells. Such inhibitory molecules can affect T cells at the effector phase via their receptor PD-1. PD-L1/PD-1 interaction has indeed been shown crucial in inducing T-cell anergy and maintaining peripheral tolerance. In order to maximize anti-tumor responses, antibodies that target the PD-1/PD-L1 axis are currently in phase I/II trials. Alternatively, a more refined approach could be the selective targeting of PD-1 in tumor-specific T cells to obtain long-term resistance against PD-1-mediated inhibition. We addressed whether this goal could be achieved by means of retroviral siRNA delivery. Effective siRNA sequences resulting in the reduction of surface PD-1 expression led to improved murine as well as human T-cell immune functions in response to PD-L1 expressing melanoma cells. These data suggest that blockade of PD-1-mediated T-cell inhibition through siRNA forms a promising approach to achieve long-lasting enhancement of tumor-specific T-cell function in adoptive T-cell therapy protocols.
Cancer Immunology and Immunotherapy 03/2010; 59(8):1173-83. · 3.70 Impact Factor
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Cancer Immunology and Immunotherapy 10/2009; 59(11):1745-56. · 3.70 Impact Factor
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ABSTRACT: Adoptive transfer of naïve CD8(+) T cells into lymphopenic recipients results both in spontaneous proliferation and in partial activation of T cells, a phenomenon termed homeostatic proliferation (HP). HP of CD8(+) T cells is dependent on host IL-7, IL-15, and MHC-class I and has been shown to prevent T-cell tolerance, reverse T-cell anergy and support T-cell-mediated tumor control in vivo. However, the initial anatomic site of HP is still under debate. Since we observed that the earliest detectable HP occurs within LN and that T cells undergoing HP retain a CD62L(bright) phenotype, we investigated the functional role of CD62L for this process. We found that CD62L-expression on T cells is required for optimal HP and HP was impaired in lymphotoxin-alphabeta(-/-) mice, indicating the necessity for intact host secondary lymphoid organ structures. Use of the LN egression inhibitor FTY720 indicated that LN structures were pivotal to yield homeostatically proliferated T cells detected in other compartments. Consistent with these results, HP-supported control of MC57-SIY tumors depended on CD62L. Our data indicate a critical role for CD62L and LN homing for the process of HP, which has implications for adoptive immunotherapy approaches of cancer.
European Journal of Immunology 09/2009; 39(11):2981-90. · 5.10 Impact Factor
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ABSTRACT: Novel immunosuppressive strategies are targeting for an antigen-specific deletion of T cells responsible for organ damage in autoimmunity and allograft rejection. Here, we present a new flow cytometry-based assay that allows the reliable and efficient detection of T cells that were eliminated in an antigen-specific fashion. A stable cell-labelling technique utilizing the two membrane dyes PKH26 and PKH67 has been combined with annexin V and 7-aminoactinomycin (7-AAD) staining to detect apoptotic cells. A differential gating strategy enabled us to determine the viability/apoptosis for each PKH-stained T cell subpopulation independently. The capability to simultaneously analyze apoptosis within T cell mixtures of different antigen specificities establishes this assay as a superior tool for the further development of novel antigen-specific immunosuppressive approaches.
Journal of immunological methods 04/2009; 344(2):98-108. · 2.35 Impact Factor
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ABSTRACT: The immune attack against malignant tumors require the concerted action of CD8+ cytotoxic T lymphocytes (CTL) as well as CD4+ T helper cells. The contribution of T cell receptor (TCR) alphabeta+ CD4- CD8- double-negative (DN) T cells to anti-tumor immune responses is widely unknown. In previous studies, we have demonstrated that DN T cells with a broad TCR repertoire are present in humans in the peripheral blood and the lymph nodes of healthy individuals. Here, we characterize a human DN T cell clone (T4H2) recognizing an HLA-A2-restricted melanoma-associated antigenic gp100-peptide isolated from the peripheral blood of a melanoma patient. Antigen recognition by the T4H2 DN clone resulted in specific secretion of IFN-gamma and TNF. Although lacking the CD8 molecule the gp100-specific DN T cell clone was able to confer antigen-specific cytotoxicity against gp100-loaded target cells as well as HLA-A2+ gp100 expressing melanoma cells. The cytotoxic capacity was found to be perforin/granzymeB-dependent. Together, these data indicate that functionally active antigen-specific DN T cells recognizing MHC class I-restricted tumor-associated antigen (TAA) may contribute to anti-tumor immunity in vivo.
Cancer Immunology and Immunotherapy 11/2008; 58(5):709-18. · 3.70 Impact Factor
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ABSTRACT: Adoptive immunotherapy for treatment of cancers and infectious diseases is often hampered by a high degree of variability in the final T cell product and in the limited in vivo function and survival of ex vivo expanded antigen-specific cytotoxic T cells (CTL). This has stimulated interest in development of standardized artificial antigen presenting cells (aAPC) to reliably expand antigen specific CTL. However, for successful immunotherapy the aAPC ex vivo generated CTL must have anti-tumor activity in vivo. Here, we demonstrate that HLA-Ig based aAPC stimulated tumor-specific CTL from human peripheral blood T lymphocytes showed robust expansion and functional activity in a human/SCID mouse melanoma model. HLA-Ig based aAPC expanded CTL were detected in the peripheral blood up to 15 days after transfer. Non-invasive bioluminescence imaging of tumor bearing mice demonstrated antigen dependent localization of transferred CTL to the tumor site. Moreover, adoptive transfer of HLA-Ig based aAPC generated CTL inhibited the tumor growth both in prevention and treatment modes of therapy and was comparable to that achieved by dendritic cell expanded CTL. Thus, our data demonstrate potential therapeutic in vivo activity of HLA-Ig based aAPC expanded CTL to control tumor growth.
Cancer Immunology and Immunotherapy 07/2008; 58(2):209-20. · 3.70 Impact Factor
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Claus Garbe,
Dirk Schadendorf,
Wilhelm Stolz,
Matthias Volkenandt,
Uwe Reinhold,
Rolf‐Dieter Kortmann,
Christoph Kettelhack,
Bernhard Frerich,
Ulrich Keilholz,
Reinhard Dummer,
Günther Sebastian,
Wolfgang Tilgen,
Gerold Schuler, Andreas Mackensen,
Roland Kaufmann,
Axel Hauschild
Journal der Deutschen Dermatologischen Gesellschaft 05/2008; 6(s1). · 1.47 Impact Factor
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ABSTRACT: Several cell-based immunotherapy strategies have been developed to specifically modulate T cell-mediated immune responses. These methods frequently rely on the utilization of tolerogenic cell-based antigen-presenting cells (APCs). However, APCs are highly sensitive to cytotoxic T-cell responses, thus limiting their therapeutic capacity. Here, we describe a novel bead-based approach to modulate T-cell responses in an antigen-specific fashion. We have generated killer artificial APCs (kappaaAPCs) by coupling an apoptosis-inducing alpha-Fas (CD95) IgM mAb together with HLA-A2 Ig molecules onto beads. These kappaaAPCs deplete targeted antigen-specific T cells in a Fas/Fas ligand (FasL)-dependent fashion. T-cell depletion in cocultures is rapidly initiated (30 minutes), dependent on the amount of kappaaAPCs and independent of activation-induced cell death (AICD). kappaaAPCs represent a novel technology that can control T cell-mediated immune responses, and therefore has potential for use in treatment of autoimmune diseases and allograft rejection.
Blood 05/2008; 111(7):3546-52. · 9.90 Impact Factor
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Claus Garbe,
Axel Hauschild,
Matthias Volkenandt,
Dirk Schadendorf,
Wilhelm Stolz,
Uwe Reinhold,
Rolf-Dieter Kortmann,
Christoph Kettelhack,
Bernhard Frerich,
Ulrich Keilholz,
Reinhard Dummer,
Günther Sebastian,
Wolfgang Tilgen,
Gerold Schuler, Andreas Mackensen,
Roland Kaufmann
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ABSTRACT: Systemic medical treatment of melanoma is administered in the adjuvant and palliative setting. Adjuvant therapy may be considered in patients with primary melanoma with more than 1.5 mm tumor thickness and with regional node metastasis. Presently no indication for systemic adjuvant chemotherapy or for adjuvant therapy with nonspecific immune-stimulatory agents outside controlled studies is seen. Interferon-alpha is the first substance in the adjuvant therapy of melanoma, which has shown to present a significant advantage to the patients in some prospective randomized studies. Good arguments for using adjuvant interferon-alpha therapy in high-risk melanoma patients exist. Both high-dose and low-dose interferon-alpha show promise. The major indications for systemic chemotherapy and chemoimmunotherapy are inoperable recurrent tumors, inoperable regional metastases and distant metastases (stage IV). As treatment in such situations is primarily palliative, the effect of any regimen on the quality of life must be carefully weighed. As a first line treatment, single agent therapy is recommended, as polychemotherapy or biochemotherapy did not show significant advantages for prolongation of survival; hence they are more toxic. An urgent need for development of new treatment modalities is necessary and general principles of experimental immunotherapy are outlined.
Melanoma Research 05/2008; 18(2):152-60. · 2.19 Impact Factor
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Claus Garbe,
Dirk Schadendorf,
Wilhelm Stolz,
Matthias Volkenandt,
Uwe Reinhold,
Rolf-Dieter Kortmann,
Christoph Kettelhack,
Bernhard Frerich,
Ulrich Keilholz,
Reinhard Dummer,
Günther Sebastian,
Wolfgang Tilgen,
Gerold Schuler, Andreas Mackensen,
Roland Kaufmann,
Axel Hauschild
Journal der Deutschen Dermatologischen Gesellschaft 05/2008; 6 Suppl 1:S9-S14. · 1.47 Impact Factor
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Claus Garbe,
Axel Hauschild,
Matthias Volkenandt,
Dirk Schadendorf,
Wilhelm Stolz,
Uwe Reinhold,
Rolf-Dieter Kortmann,
Christoph Kettelhack,
Bernhard Frerich,
Ulrich Keilholz,
Reinhard Dummer,
Günther Sebastian,
Wolfgang Tilgen,
Gerold Schuler, Andreas Mackensen,
Roland Kaufmann
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ABSTRACT: The primary treatment of a melanoma is surgical excision. An excisional biopsy is preferred, and safety margins of 1 cm for tumor thickness up to 2 mm and 2 cm for higher tumor thickness should be applied either at primary excision or in a two-step procedure. When dealing with facial, acral or anogenital melanomas, micrographic control of the surgical margins may be preferable to allow reduced safety margins and conservation of tissue. The sentinel lymph node biopsy should be performed in patients whose primary melanoma is thicker than 1.0 mm and this operation should be performed in centers where both the operative and nuclear medicine teams are experienced. In clinically identified lymph node metastases, radical lymph node dissection is considered standard therapy. If distant metastases involve just one internal organ and operative removal is feasible, then surgery should be seen as therapy of choice. Radiation therapy for the primary treatment of melanoma is indicated only in those cases in which surgery is impossible or not reasonable. In regional lymph nodes, radiation therapy is usually recommended when excision is not complete (R1 resection) or if the nodes are inoperable. In distant metastases, radiation therapy is particularly indicated in bone metastases, brain metastases and soft tissue metastases.
Melanoma Research 03/2008; 18(1):61-7. · 2.19 Impact Factor
