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Carmen Scheibenbogen

Publications and source records attributed to Carmen Scheibenbogen.

At least 19 recordsLinked to original sources
PubMed2006

Identification of a highly immunogenic HLA-A*01-binding T cell epitope of WT1.

PURPOSE: The transcription factor Wilms tumor protein 1 (WT1) belongs to a new generation of tumor antigens, as it is essential for tumor cell proliferation and is highly expressed in various hematologic and solid malignancies. The aim of this study was to apply a modified reverse immunology strategy to identify immunogenic epitopes of WT1 which could be useful for immunotherapy. EXPERIMENTAL DESIGN: Potential HLA-A*01 epitopes predicted by a MHC binding algorithm were screened for recognition by peripheral blood mononuclear cells (PBMC) from patients with spontaneous T cell responses using intracellular cytokine cytometry. Epitope processing was shown by proteasomal cleavage. Epitope-specific T cells were generated from CD4+CD25+ regulatory T cell-depleted PBMC. RESULTS: One of five predicted HLA-A*01-binding candidate epitopes showed high immunogenicity as 5 of 14 patients with hematologic malignancies had WT1.317-327-reactive T cells ranging from 0.4% to 1.5% of CD3+CD8+ T cells. Proteasomal degradation assays indicated the cleavage of WT1.317-327. The depletion of regulatory T cells from PBMCs enabled the rapid expansion of WT1.317-327-specific CTL, whereas no CTL could be generated from unfractionated PBMC. WT1.317-327-specific CTL efficiently lysed an autologous WT1-expressing tumor cell line but not HLA-A*01-negative WT1-expressing tumor cells. Immunogenicity of the epitope across histologies was verified by the demonstration of spontaneous ex vivo WT1.317-327-specific T cell responses in two of six patients with HLA-A*01-positive melanoma or lung cancer. CONCLUSION: In this study, a modified reverse immunology strategy was employed to identify a first immunogenic HLA-A*01-restricted T cell epitope of the tumor antigen WT1, which is of considerable interest for use in vaccination trials.

Antigens, Neoplasm↗
PubMed2006

Addition of GM-CSF to a peptide/KLH vaccine results in increased frequencies of CXCR3-expressing KLH-specific T cells.

T-cell trafficking is determined by expression patterns of chemokine receptors. The chemokine receptor CXCR3 is expressed on a subpopulation of type 1 T cells and plays an important role for migration of T cells into inflamed and tumor tissues. Here, we studied the chemokine receptor expression on specific T cells generated against the neoantigen keyhole limpet hemocyanin (KLH) in patients who had been immunized in the context of a tumor peptide vaccination trial with or without the adjuvant granulocyte-macrophage colony-stimulating factor (GM-CSF). In patients immunized in the presence of GM-CSF the fraction of CXCR3(+) KLH-specific T cells was significantly higher than in patients immunized in the absence of GM-CSF (median 45 vs. 20%, P = 0.001). In contrast, the chemokine receptor CCR4, associated with migration to the skin was found in both cohorts on less than 10% of KLH-specific T cells. These results show that CXCR3 expression on vaccine-induced T cells can be modulated by modifying the local vaccine milieu.

Adjuvants, Immunologic↗
PubMed2006

Cross-presentation of HLA class I epitopes from influenza matrix protein produced in Saccharomyces cerevisiae.

Here we report that genetically engineered yeast of the strain Saccharomyces cerevisiae expressing full-length influenza matrix protein (IMP) attached to the yeast cell wall are a very versatile host for antigen delivery. Feeding of dendritic cells with either intact yeast expressing IMP protein or soluble IMP protein cleaved off the cell wall resulted in protein uptake, processing and cross-presentation of IMP-derived peptides. This process was analysed using previously established T-cell lines recognizing the immuno-dominant 58-66 peptide when presented by HLA-A2*0201 complexes. In addition, IMP(58-66)/HLA-A2*0201-specific antibodies were selected from a naive phage library which confirmed that peptide presentation was an active process of endocellular uptake and not just a result of external peptide loading. Moreover, MHC peptide antibodies could block the recognition of peptide-presenting dendritic cells by IMP(58-66)-specific T-cells in a dose dependent manner. There was no difference in T-cell recognition when either intact yeast or yeast cell extracts were used for DC feeding. Together, these data demonstrate that yeast derived proteins either in their soluble form or as part of a whole yeast vaccine are taken up, processed and presented by dendritic cells in HLA class I context.

Antibody Specificity↗
PubMed2006

Chemokine receptor CCR6 expression level and liver metastases in colorectal cancer.

PURPOSE: The liver is the primary organ of metastasis in colorectal cancer (CRC). Chemokine receptor CCR6 is expressed on a subset of T cells and is associated with their migration into the liver. This study was performed to analyze a possible association between CCR6 expressed by primary CRC and liver metastases. PATIENTS AND METHODS: CCR6 expression levels were evaluated by immunohistology in 64 CRC primary tumor specimens. Twenty-four of 64 patients had synchronous liver metastases. Evaluation of immunostaining was performed semiquantitatively by visual assessment and quantitatively by digital image analysis (DIA). Multiple logistic regression analysis was performed to assess relevant parameters for liver metastases. RESULTS: CCR6 expression was verified in all 64 primary tumor specimens with considerable variations in intensity; 21 tumors (33%) demonstrated weak CCR6 staining, 32 (50%) demonstrated intermediate staining, and 11 (17%) demonstrated strong staining. Quantitative assessment by DIA showed an up to 5-log difference in CCR6 values. CCR6 staining was significantly stronger in tumor cells compared with adjacent colon epithelial cells (P < .0005). Multiple logistic regression analysis, controlling for age, sex, tumor stage, nodal status, pathologic grade, and preoperative carcinoembryonic antigen levels, revealed that CCR6 staining in the primary tumor was independently associated with the presence of liver metastases (odds ratio = 2.1; P = .002). CONCLUSION: The association between expression level of CCR6 in primary CRC and synchronous liver metastases suggests that CCR6 and its ligand may be involved in the metastatic spread to the liver. Therefore, CCR6 may be a potential target for specific therapeutic interventions.

Aged↗
PubMed2006

Immune monitoring of T-cell responses in cancer vaccine development.

Monitoring cellular immune responses is one prerequisite for rational development of cancer vaccines. The primary objective of immune monitoring is to determine the efficacy of a vaccine to induce or augment a specific T-cell response. Further questions relate to the prevalence and functional relevance of spontaneous tumor-directed immune responses, the functional characteristics of T-cell responses, and, finally and most importantly, the relationship between immune monitoring assay results and clinical end points. The issue of T-cell monitoring has become more complex as different types and generations of assays have been adopted during the past decade and both standardization and validation of assays have often been insufficient. Because the development of assays parallel the clinical development of cancer vaccines, technical advances have been achieved simultaneously with broadening understanding of cancer immunity. Suitable animal models for immune monitoring are, however, lacking, because preclinical vaccine development in rodents does not allow serial immune monitoring of the peripheral blood, as is commonly used in patients. The current situation is characterized by a lack of universal standards for T-cell assessment, uncertainty about the association between immune monitoring assay results and clinical antitumor end points, and lack of knowledge regarding the contribution of different aspects of T-cell function to clinical efficacy. It is acknowledged that T-cell monitoring will have to be validated in large trials with clinically effective vaccines, but this necessity should not discourage the current application of novel assays within clinical trials of all stages.

Animals↗
PubMed2005

Lymphomas are sensitive to perforin-dependent cytotoxic pathways despite expression of PI-9 and overexpression of bcl-2.

There is considerable interest in immunotherapeutic approaches for lymphoma. The expression of proteinase inhibitor 9 (PI-9), a molecule that inactivates granzyme B, is considered an immune escape mechanism in lymphoma. Further, lymphomas frequently overexpress the antiapoptotic molecule bcl-2, which is able to inhibit perforin-dependent cytotoxic pathways. In this study, the impact of PI-9 and bcl-2 expression on the sensitivity of lymphomas to T- and natural killer (NK) cell-mediated cytotoxicity was analyzed. We found PI-9 expression in 10 of 18 lymphoma cell lines and in 9 of 14 primary lymphomas. Overexpression of bcl-2 was found in 8 of 18 cell lines and in 12 of 14 primary lymphomas. All lymphoma cells were sensitive to cytolysis by specific T cells and cytokine-activated NK cells, and no difference in sensitivity was observed with respect to PI-9 or bcl-2 expression. Cytolysis was mediated predominantly through perforin-dependent pathways despite expression of PI-9 and bcl-2. Interestingly, the majority of lymphoma cells were resistant to cytolysis by resting allogeneic NK cells. This was due to the failure of lymphomas to induce degranulation of resting NK cells. These results show that resistance to perforin-dependent pathways is not a relevant immune escape mechanism in lymphoma and therefore is unlikely to impair clinical outcome of immunotherapeutic approaches.

Cytokines↗
PubMed2005

Peptide vaccination after repeated resection of metastases can induce a prolonged relapse-free interval in melanoma patients.

This pilot study was carried out to gain a first insight into the effects of peptide vaccination in melanoma patients in the high-risk adjuvant disease setting. From the adjuvant peptide vaccination studies carried out in our institution since 1998, we identified all melanoma patients with a history of at least 3 completely resected metastases during the year preceding enrollment into the trial and describe the clinical and immunologic observations. Out of a total of 44 patients with resected cutaneous melanoma entered into adjuvant peptide vaccination trials, 9 patients were identified with more than 3 metastases in the year before vaccination. After initiation of vaccination, 2 patients remained relapse-free for 27 and 42+ months, 2 patients experienced single or several initial relapses and subsequent relapse-free intervals of 18 and 65+ months, whereas 5 patients progressed. In both patients with relapse after prolonged relapse-free intervals, the relapses were initially confined to the small intestine and could be resected. Induction or boosting of functional tyrosinase peptide-specific T cells was noted in 6 of 8 patients, including all 4 patients with prolonged relapse-free intervals. In conclusion, adjuvant peptide vaccination was associated with cessation of recurrences in 4 of 9 patients, of whom all 4 had an immunologic response to the vaccine.

Adjuvants, Immunologic↗
PubMed2005

T cell responses against tumor associated antigens and prognosis in colorectal cancer patients.

INTRODUCTION: Spontaneous T cell responses against specific tumor-associated antigens (TAA) are frequently detected in peripheral blood of tumor patients of various histiotypes. However, little is known about whether these circulating, spontaneously occurring, TAA-reactive T cells influence the clinical course of disease. METHODS: Fifty-four HLA-A2 positive colorectal cancer patients had been analyzed for the presence of T cell responses against epitopes derived from the TAA Ep-CAM, her-2/neu, and CEA either by ELISPOT assay or by intracellular cytokine staining. Then, Kaplan-Meier survival analysis was performed comparing T-cell-responders and T-cell-non-responders. For comparison, a group of T-cell-non-responders was compiled stringently matched to T-cell-responders based on clinical criteria and also analyzed for survival. RESULTS: Sixteen out of 54 patients had a detectable T cell response against at least one of the three tested TAA. Two out of 21 patients (9.5%) with limited stage of disease (UICC I and II) and 14 out of 33 patients (42.4%) with advanced disease (UICC III and IV) were T cell response positive. Comparing all T-cell-responders (n = 16) and all T-cell-non-responders (n = 38), no survival difference was found. In an attempt to reduce the influence of confounding clinical factors, we then compared 16 responders and 16 non-responders in a matched group survival analysis; and again no survival difference was found (p = 0.7). CONCLUSION: In summary, we found no evidence that spontaneous peripheral T cell responses against HLA-A2-binding epitopes of CEA, her-2/neu and Ep-CAM are a strong prognostic factor for survival.

Journal Article↗
PubMed2005

Addition of histamine to interleukin 2 treatment augments type 1 T-cell responses in patients with melanoma in vivo: immunologic results from a randomized clinical trial of interleukin 2 with or without histamine (MP 104).

PURPOSE: Preclinical investigations suggest that histamine dihydrochloride (HDC) protects T cells and natural killer cells from inhibition by monocyte-derived reactive oxygen metabolites and synergizes with interleukin (IL) 2 in inducing T-cell activation. Here, we investigate whether this mechanism is operational in patients with melanoma treated with HDC as an adjunct to IL-2. EXPERIMENTAL DESIGN: Melanoma patients having liver metastases were treated with IL-2 with or without HDC within a randomized, multicenter, phase III trial. The effect of HDC on type 1 and type 2 T-cell cytokine production was investigated in peripheral blood samples from 19 patients with the use of intracellular cytokine flow cytometry. Melanoma-specific T-cell responses were analyzed in eight HLA-A2-positive patients. RESULTS: Frequencies of CD3+ T cells producing IFN-gamma (type 1 T cells) in response to phorbol myristate acetate/ionomycin increased (median, 1.8-fold) in patients receiving IL-2 plus HDC but not in those receiving IL-2 alone (P < 0.01 for comparison between arms). In contrast, the number of IL-13-producing type 2 T cells that increased in patients after treatment with IL-2 was not modulated by HDC. Melanoma- and tyrosinase-specific IFN-gamma and IL-13-producing T cells were detected in two of four HLA-A2-positive patients with melanoma following treatment with HDC + IL-2. CONCLUSIONS: Treatment of patients with stage IV melanoma with HDC in combination with IL-2 increases type 1 T-cell responses and may promote induction of melanoma-specific T cells. These effects are of relevance for tumor immunotherapy and provide a potential mechanism for the clinical efficacy of HDC added to IL-2.

CD3 Complex↗
PubMed2004

Quantitative detection of circulating tumor cells in cutaneous and ocular melanoma and quality assessment by real-time reverse transcriptase-polymerase chain reaction.

PURPOSE: Inconsistent reports on the detection of melanoma cells in peripheral blood by reverse transcriptase-PCR (RT-PCR) have resulted in uncertainty on the prognostic value of circulating melanoma cells. EXPERIMENTAL DESIGN: We developed real-time RT-PCR assays for quantitation of tyrosinase, MelanA/MART1, and gp100 and for porphobilinogen deaminase housekeeping gene. Melanoma tissue (n = 18), peripheral blood samples from healthy donors (n = 21), and patients with cutaneous (n = 122) and uveal (n = 64) melanoma from our institution were analyzed. For quality control, an additional 251 samples from ongoing multicenter studies were compared with in-house samples. RESULTS: Tyrosinase was not detected in healthy donor blood samples. For the two other markers, cutoff values had to be defined to distinct patient samples from controls. Patients with stage IV uveal and cutaneous melanoma expressed all three markers more frequently and at higher levels in peripheral blood as compared with earlier stages. The variation of expression was 4 logs and correlated with tumor load and serum lactate dehydrogenase. In 2 of 3 uveal melanoma patients, detection of circulating tumor cells preceded the development of liver metastases. The diagnostic sensitivity was optimal in blood samples containing >0.1pg/ microl porphobilinogen deaminase (95.7% of in-house samples and 57.4% of multicenter samples). CONCLUSIONS: Real-time RT-PCR is able to quantitatively define the quality of a sample and provides quantitative data for melanoma markers. Disparities in the results of previous studies may be attributable to undetected differences in sample quality. The prognostic relevance of this assay is currently under evaluation in several prospective randomized trials.

Antigens, Neoplasm↗
PubMed2004

Independent prognostic factors for distant metastases and survival in patients with primary uveal melanoma.

Adjuvant treatment strategies in uveal melanoma require determination of prognostic factors. Patients, who received primary therapy in 1994 and 1995 at our institution, were analysed. Of 271 patients 85% and 71% were available for follow up of 4 and 5 years. Forty three patients (15.9%) developed metastases. Kaplan-Meier analysis revealed a 5-year progression free survival (PFS) of 79% for the whole patient cohort. Extraocular tumor growth (EOG), ciliary body involvement or a largest tumor diameter (LTD) >14 mm were associated with a significantly lower 5-year PFS of 28%, 61.4% or 67.6%. In multivariate analysis time to progression was significantly associated with ciliary body involvement and LTD, and survival was associated with ciliary body involvement. Ciliary body involvement profoundly increased the risk for metastases (hazard ratio 6.9, P<0.001) within the first 3 years. This study determined patients with ciliary body involvement to be candidates for future adjuvant therapeutic interventions.

Adolescent↗
PubMed2004

Functional CCR9 expression is associated with small intestinal metastasis.

In general, metastases to the small intestine are rare, and mostly occur in melanoma. CCR9 has been shown to be the principal chemokine receptor for the thymus expressed chemokine (TECK), a chemokine selectively expressed in the small intestine and thymus. Here we show that CCR9 is highly expressed on melanoma cells and all melanoma cell lines isolated from small intestinal metastases, and on a proportion of cell lines from other sites. Only melanoma cells and cell lines from small intestinal metastases, however, were responsive to the CCR9 ligand TECK, as assessed by receptor downregulation and by actin polymerization. CCR9 expression was also found on the adenocarcinoma cell line CaCo-2 expressing characteristics of enterocytic differentiation, but not on any other cell line isolated from colorectal, breast, and lung cancer. Our data provide evidence that the aberrant functional cell surface expression of an organ-specific chemokine receptor is associated with metastasis to this site. The regulation of receptor function seems to be a critical step in the metastatic process.

Actins↗
PubMed2004

Immunological monitoring of cancer vaccine therapy.

Immunological treatment of malignant diseases in humans aiming at the induction and proliferation of antigen-specific T cells has made rapid progress in recent years. A growing number of tumour-associated antigens, potentially synergistic combinations with adjuvants, and various routes of application provide new opportunities for cancer vaccination. Therefore, a highly accurate assessment of vaccine-induced T cell responses is required. Three T cell assays (tetramers, intracellular cytokine flow cytometry and ELISPOT assay) have emerged as first-line methods for monitoring T cell induction during vaccination. These assays are relatively easy to perform, reliable, sensitive and allow an ex vivo T cell analysis at the single cell level. Although at this stage assays are not a defined surrogate marker for clinical efficacy, they already provide information concerning the immunological potency of a given vaccine. In particular, comparing immune responses under various treatment conditions will help to develop more clinically efficient tumour vaccination. Novel assays, such as CD107 staining, human leukocyte antigen/green fluorescent protein-antigen-presenting cells or microarrays, and assays determining functions, such as proliferation assays, are beginning to complement first-line monitoring assays.

Antigen-Antibody Reactions↗
PubMed2003

Human tumor-derived heat shock protein 96 mediates in vitro activation and in vivo expansion of melanoma- and colon carcinoma-specific T cells.

Heat shock proteins (hsp) 96 play an essential role in protein metabolism and exert stimulatory activities on innate and adaptive immunity. Vaccination with tumor-derived hsp96 induces CD8(+) T cell-mediated tumor regressions in different animal models. In this study, we show that hsp96 purified from human melanoma or colon carcinoma activate tumor- and Ag-specific T cells in vitro and expand them in vivo. HLA-A*0201-restricted CD8(+) T cells recognizing Ags expressed in human melanoma (melanoma Ag recognized by T cell-1 (MART-1)/melanoma Ag A (Melan-A)) or colon carcinoma (carcinoembryonic Ag (CEA)/epithelial cell adhesion molecule (EpCAM)) were triggered to release IFN-gamma and to mediate cytotoxic activity by HLA-A*0201-matched APCs pulsed with hsp96 purified from tumor cells expressing the relevant Ag. Such activation occurred in class I HLA-restricted fashion and appeared to be significantly higher than that achieved by direct peptide loading. Immunization with autologous tumor-derived hsp96 induced a significant increase in the recognition of MART-1/Melan-A(27-35) in three of five HLA-A*0201 melanoma patients, and of CEA(571-579) and EpCAM(263-271) in two of five HLA-A*0201 colon carcinoma patients, respectively, as detected by ELISPOT and HLA/tetramer staining. These increments in Ag-specific T cell responses were associated with a favorable disease course after hsp96 vaccination. Altogether, these data provide evidence that hsp96 derived from human tumors can present antigenic peptides to CD8(+) T cells and activate them both in vitro and in vivo, thus representing an important tool for vaccination in cancer patients.

Antigen Presentation↗
PubMed2003

Natural T cell immunity against cancer.

It has long been a matter of debate whether tumors are spontaneously immunogenic in patients. With the availability of sensitive methods, naturally occurring T cells directed against tumor-associated antigens (TAAs) can be frequently detected in cancer patients. In this review, we summarize the current data on T cell responses to TAAs in various malignancies, including melanoma, colorectal cancer, leukemia, and breast cancer. T cell responses against various antigens, including melanoma differentiation antigens, carcinoembryonic antigen, epithelial cell adhesion molecule, her-2/neu, Wilms' tumor protein, proteinase 3, NY-ESO-1, and surviving, have been reported in a substantial number of patients. In contrast, other TAAs, including most antigens of the MAGE family, do not usually elicit spontaneous T cell responses. A distinction between direct ex vivo T cell responses and in vitro-generated T cell responses is provided because in vitro stimulation results in quantitative and functional changes of T cell responses. The possible role of TAA-specific T cells in immunosurveillance and tumor escape and the implications for immunological treatment strategies are discussed. Naturally occurring T cells against TAAs are a common phenomenon in tumor patients. Understanding the mechanisms and behavior of natural TAA-specific T cells could provide crucial information for rational development of more efficient T cell-directed immunotherapy.

Antibodies, Monoclonal↗
PubMed2003

Bone marrow contains melanoma-reactive CD8+ effector T cells and, compared with peripheral blood, enriched numbers of melanoma-reactive CD8+ memory T cells.

Circulating melanoma-specific T cells can be frequently detected in patients with melanoma. Effective T-cell immunity and tumor surveillance, however, requires the presence of specific T cells in tissues populated by tumor cells. The bone marrow (BM) is a compartment frequently harboring micrometastatic tumor cells. Here, we compared directly ex vivo in peripheral blood (PB) and BM frequencies and differentiation phenotypes of T cells reactive with the melanoma-associated antigen tyrosinase and with autologous melanoma cells. Using intracellular cytokine and tetramer staining, we detected tyrosinase- and melanoma-reactive CD3+CD8+ T cells in the BM in similar or enhanced frequencies as in PB. Additional characterization of the differentiation subset using CD45RA and CCR7 revealed the presence of specific effector and memory T cells in the BM in all five patients analyzed. Remarkably, the frequency of tyrosinase- and melanoma-specific memory T cells was significantly increased in BM compared with PB. Thus, the BM may be an important compartment for tumor surveillance harboring a tumor-specific memory T-cell pool in addition to effector T cells.

Bone Marrow Cells↗