Melanoma: Dietrich PY

Guggisberg D, Cerottini JP, Krischer J, Braun R, Dietrich PY, Liénard D, Anonymous00229. · Département hospitalo-universitaire romand de dermatologie et vénéréologie, Lausanne et Genève. · Rev Med Suisse Romande. · Pubmed #11887568 No free full text.

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Romero P, Valmori D, Pittet MJ, Zippelius A, Rimoldi D, Lévy F, Dutoit V, Ayyoub M, Rubio-Godoy V, Michielin O, Guillaume P, Batard P, Luescher IF, Lejeune F, Liénard D, Rufer N, Dietrich PY, Speiser DE, Cerottini JC. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, Lausanne branch, University Hospital (CHUV), Lausanne, Switzerland. · Immunol Rev. · Pubmed #12445283 No free full text.

Abstract: Some cancer patients mount spontaneous T- and B-cell responses against their tumor cells. Autologous tumor reactive CD8 cytolytic T lymphocyte (CTL) and CD4 T-cell clones as well as antibodies from these patients have been used for the identification of genes encoding the target antigens. This knowledge opened the way for new approaches to the immunotherapy of cancer. In this review, we describe the characterization of the structure-function properties of the melanocyte/melanoma tumor antigen Melan-A/MART-1, the assessment of the T-cell repertoire available against this antigen in healthy individuals, and the analysis of naturally acquired and/or vaccine-induced CTL responses to this antigen in patients with metastatic melanoma.

van Baren N, Bonnet MC, Dréno B, Khammari A, Dorval T, Piperno-Neumann S, Liénard D, Speiser D, Marchand M, Brichard VG, Escudier B, Négrier S, Dietrich PY, Maraninchi D, Osanto S, Meyer RG, Ritter G, Moingeon P, Tartaglia J, van der Bruggen P, Coulie PG, Boon T. · Ludwig Institute for Cancer Research, 74 avenue Hippocrate, UCL7459, B-1200 Brussels, Belgium; e-mail: · J Clin Oncol. · Pubmed #16061912 No free full text.

Abstract: PURPOSE: To evaluate the toxicity, antitumoral effectiveness, and immunogenicity of repeated vaccinations with ALVAC miniMAGE-1/3, a recombinant canarypox virus containing a minigene encoding antigenic peptides MAGE-3(168-176) and MAGE-1(161-169), which are presented by HLA-A1 and B35 on tumor cells and can be recognized by cytolytic T lymphocytes (CTLs). MATERIALS AND METHODS: The vaccination schedule comprised four sequential injections of the recombinant virus, followed by three booster vaccinations with the MAGE-3(168-176) and MAGE-1(161-169) peptides. The vaccines were administered, both intradermally and subcutaneously, at 3-week intervals. RESULTS: Forty patients with advanced cancer were treated, including 37 melanoma patients. The vaccines were generally well tolerated with moderate adverse events, consisting mainly of transient inflammatory reactions at the virus injection sites. Among the 30 melanoma patients assessable for tumor response, a partial response was observed in one patient, and disease stabilization in two others. The remaining patients had progressive disease. Among the patients with stable or progressive disease, five showed evidence of tumor regression. A CTL response against the MAGE-3 vaccine antigen was detected in three of four patients with tumor regression, and in only one of 11 patients without regression. CONCLUSION: Repeated vaccination with ALVAC miniMAGE-1/3 is associated with tumor regression and with a detectable CTL response in a minority of melanoma patients. There is a significant correlation between tumor regression and CTL response. The contribution of vaccine-induced CTL in the tumor regression process is discussed in view of the immunologic events that could be analyzed in detail in one patient.

Liénard D, Rimoldi D, Marchand M, Dietrich PY, van Baren N, Geldhof C, Batard P, Guillaume P, Ayyoub M, Pittet MJ, Zippelius A, Fleischhauer K, Lejeune F, Cerottini JC, Romero P, Speiser DE. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. · Cancer Immun. · Pubmed #15149168 links to  free full text

Abstract: The purpose of this study was to test melanoma vaccines consisting of peptides and immunological adjuvants for optimal immunogenicity and to evaluate laboratory immune monitoring for in vivo relevance. Forty-nine HLA-A2 positive patients with Melan-A positive melanoma were repeatedly vaccinated with Melan-A peptide, with or without immune adjuvant AS02B (QS21 and MPL) or IFA. Peptide-specific CD8 T cells in PBLs were analyzed ex vivo using fluorescent HLA-A2/Melan-A multimers and IFN-gamma ELISPOT assays. The vaccines were well tolerated. In vivo expansion of Melan-A-specific CD8 T cells was observed in 13 patients (1/12 after vaccination with peptide in AS02B and 12/17 after vaccination with peptide in IFA). The T cells produced IFN-gamma and downregulated CD45RA and CD28. T-cell responses correlated with inflammatory skin reactions at vaccine injection sites (P < 0.001) and with DTH reaction to Melan-A peptide (P < 0.01). Twenty-six of 32 evaluable patients showed progressive disease, whereas 4 patients had stable disease. The two patients with the strongest Melan-A-specific T-cell responses experienced regression of metastases in skin, lymph nodes, and lung. We conclude that repeated vaccination with Melan-A peptide in IFA frequently leads to sustained responses of specific CD8 T cells that are detectable ex vivo and correlate with inflammatory skin reactions.

Rochlitz C, Dreno B, Jantscheff P, Cavalli F, Squiban P, Acres B, Baudin M, Escudier B, Heinzerling L, Morant R, Herrmann R, Dietrich PY, Dummer R. · Departement Innere Medizin, Abteilung für Onkologie, Kantonsspital, Petersgraben 4, CH-4031 Basel, Switzerland. · Cancer Gene Ther. · Pubmed #11896446 links to  free full text

Abstract: BACKGROUND: Systemic IL-2 has shown some activity in metastatic melanoma, but its use is severely limited by toxicity. TG2001 is a product in which the human IL-2 cDNA was incorporated into the genome of Vero cells, a monkey fibroblast cell line. The goal of this intratumorally applied therapy was to create an antitumor immune response stimulated by xeno-antigens and local production of IL-2 in the close vicinity of tumor-specific antigens. TG2001 was reported to have a good safety profile in two previous dose-escalating phase I studies performed in 18 patients with various solid tumors, with encouraging clinical responses in three patients. The objectives of this study were to evaluate the tolerance and incidence of tumor regression in patients with metastatic melanoma, following repeated administration of Vero-IL-2 cells. PATIENTS AND METHODS: This was on open-label, randomized phase II study comparing two doses of Vero-IL-2, 5x10(5) and 5x10(6) cells. Twenty-eight patients with metastatic melanoma were enrolled in the study, 14 in each treatment group. Patients received TG2001 by intratumoral injection on days 1, 3, and 5 every 4 weeks for four cycles, and every 8 weeks thereafter, until evidence of progressive disease (PD). Criteria for patient selection included histologically proven metastatic melanoma, with one tumor accessible for product administration, and at least another tumor site for response assessment. Evaluation included tumor measurements, humoral and T cell-mediated local and systemic immune response, humoral response to Vero cells, adverse events and standard laboratory parameters. RESULTS: None of the patients achieved a confirmed objective response. Stable disease (SD) was seen in six (43%) and eight patients (57%) at the 5x10(5) and the 5x10(6) dose level, respectively. Two patients, one in each group, died during the study (i.e., within 1 month after the last injection) due to PD. Three patients exhibited antibody responses to Vero cells. T-cell immunity, serum cytokine levels and cytokine mRNA expression in tumor biopsies did not show meaningful alterations after therapy, except for a trend toward an increase in intratumoral TH2 cytokine (IL-4 and/or IL-10) levels. The study drug was well tolerated at both dose levels and side effects mainly consisted of injection site pain and erythema, and pyrexia. CONCLUSION: The intratumoral administration of TG2001 was generally well tolerated in patients with metastatic melanoma, and transient disease stabilization was observed in 50% of patients.

Rochlitz C, Jantscheff P, Bongartz G, Dietrich PY, Quiquerez AL, Schatz C, Mehtali M, Courtney M, Tartour E, Dorval T, Fridman WH, Herrmann R. · Division of Medical Oncology, Kantonsspital, Basal, Switzerland. · Cancer Gene Ther. · Pubmed #10359213 links to  free full text

Abstract: On the basis of compelling preclinical data in cats and dogs, we initiated a clinical gene therapy study in nine patients with advanced solid tumors using xenogeneic fibroblasts secreting human interleukin (IL)-2 (Vero-IL-2 cells). Cohorts of three successive patients with tumors accessible to computed tomography- or ultrasound-guided injection were treated repeatedly with 5 x 10(5), 5 x 10(6), or 5 x 10(7) Vero-IL-2 cells. The endpoints of the study were feasibility, toxicity, and the clinical and biological effects of this novel approach to immunotherapy of cancer. Histopathological, immunological, and molecular analyses were performed on biopsy specimens of tumors and blood samples before, during, and after treatment. Treatment was well tolerated, and toxicity consisted of transient fever in one patient and short-lived, mild itching and erythema in two others. One patient with soft-tissue sarcoma showed a reduction of >90% and >50% of the volume of two distant, noninjected metastases, lasting for 29+ and 26 months, respectively. Four other patients showed stabilization of their disease for 3-9 months; of these patients, one with melanoma developed marked vitiligo. We conclude that repeated injections of < or =5 x 10(7) Vero-IL-2 cells are feasible and safe in heavily pretreated patients with advanced solid tumors. An additional evaluation of an intratumoral application of Vero-IL-2 seems warranted.

Marchand M, van Baren N, Weynants P, Brichard V, Dréno B, Tessier MH, Rankin E, Parmiani G, Arienti F, Humblet Y, Bourlond A, Vanwijck R, Liénard D, Beauduin M, Dietrich PY, Russo V, Kerger J, Masucci G, Jäger E, De Greve J, Atzpodien J, Brasseur F, Coulie PG, van der Bruggen P, Boon T. · Ludwig Institute for Cancer Research, Brussels Branch, and Université Catholique de Louvain, Belgium. · Int J Cancer. · Pubmed #9935203 No free full text.

Abstract: Thirty-nine tumor-bearing patients with metastatic melanoma were treated with 3 subcutaneous injections of the MAGE-3.A1 peptide at monthly intervals. No significant toxicity was observed. Of the 25 patients who received the complete treatment, 7 displayed significant tumor regressions. All but one of these regressions involved cutaneous metastases. Three regressions were complete and 2 of these led to a disease-free state, which persisted for more than 2 years after the beginning of treatment. No evidence for a cytolytic T lymphocyte (CTL) response was found in the blood of the 4 patients who were analyzed, including 2 who displayed complete tumor regression. Our results suggest that injection of the MAGE-3.A1 peptide induced tumor regression in a significant number of the patients, even though no massive CTL response was produced.

Inan I, De Sousa S, Myers PO, Bouclier B, Dietrich PY, Hagen ME, Morel P. · Visceral Surgery Division, Department of Surgery, Geneva University Hospital, Rue Micheli-du-Crest 24, CH-1211, Geneva, Switzerland. · World J Surg Oncol. · Pubmed #18706116 links to  free full text

Abstract: BACKGROUND: Pleural or peritoneal effusions (ascites) are frequent in terminal stage malignancies. Medical management may be hazardous. METHODS: A 60-year-old man with metastatic malignant melanoma presented refractory ascites as well as bilateral pleural effusions. After failure of the medical treatment, bilateral pleural aspiration and paracentesis became necessary two to three times a week. A multi perforated 15F silicone catheter connected with a subcutaneous port was implanted in peritoneal and both pleural cavities surgically under general anesthesia. Leakage around the catheter is prevented by subcutaneous tunneling. Surgical technique is described and illustrated in a video. RESULTS: Implanted systems were immediately operational. Follow up period was 41 days. Each port was accessed 10 times and a total of 65'200 ml of fluid was drained. By the end of the forth week, pleural effusions diminished, systems were controlled for permeability and chest x-rays confirmed absence of effusion. CONCLUSION: Implanted port systems for refractory ascites and pleural effusions avoid morbidity and the patient's anxiety related to repeated puncture-aspiration. Large catheter diameter allows an easy and fast drainage of large volumes. Compared to chronic indwelling catheters, subcutaneous location of port system allows an entire integration, giving the patient a total liberty in daily life between two sessions of drainage. Drainage can be performed in an outpatient basis as an ambulatory procedure. This patient-friendly technique may be a treatment option in case of failure of other techniques.

Le Gal FA, Widmer VM, Dutoit V, Rubio-Godoy V, Schrenzel J, Walker PR, Romero PJ, Valmori D, Speiser DE, Dietrich PY. · Laboratory of Tumor Immunology, Division of Oncology, Department of Internal Medicine, University Hospital, Geneva, Switzerland. · J Invest Dermatol. · Pubmed #17039243 links to  free full text

Abstract: Tumor antigen-specific cytotoxic T cells (CTLs) play a major role in the adaptive immune response to cancers. This CTL response is often insufficient because of functional impairment, tumor escape mechanisms, or inhibitory tumor microenvironment. However, little is known about the fate of given tumor-specific CTL clones in cancer patients. Studies in patients with favorable outcomes may be very informative. In this longitudinal study, we tracked, quantified, and characterized functionally defined antigen-specific T-cell clones ex vivo, in peripheral blood and at tumor sites, in two long-term melanoma survivors. MAGE-A10-specific CD8+ T-cell clones with high avidity to antigenic peptide and tumor lytic capabilities persisted in peripheral blood over more than 10 years, with quantitative variations correlating with the clinical course. These clones were also found in emerging metastases, and, in one patient, circulating clonal T cells displayed a fully differentiated effector phenotype at the time of relapse. Longevity, tumor homing, differentiation phenotype, and quantitative adaptation to the disease phases suggest the contribution of the tracked tumor-reactive clones in the tumor control of these long-term metastatic survivor patients. Focusing research on patients with favorable outcomes may help to identify parameters that are crucial for an efficient antitumor response and to optimize cancer immunotherapy.

Speiser DE, Baumgaertner P, Barbey C, Rubio-Godoy V, Moulin A, Corthesy P, Devevre E, Dietrich PY, Rimoldi D, Liénard D, Cerottini JC, Romero P, Rufer N. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, University Hospital of Lausanne, Lausanne, Switzerland. · J Immunol. · Pubmed #16818795 links to  free full text

Abstract: Despite major progress in T lymphocyte analysis in melanoma patients, TCR repertoire selection and kinetics in response to tumor Ags remain largely unexplored. In this study, using a novel ex vivo molecular-based approach at the single-cell level, we identified a single, naturally primed T cell clone that dominated the human CD8(+) T cell response to the Melan-A/MART-1 Ag. The dominant clone expressed a high-avidity TCR to cognate tumor Ag, efficiently killed tumor cells, and prevailed in the differentiated effector-memory T lymphocyte compartment. TCR sequencing also revealed that this particular clone arose at least 1 year before vaccination, displayed long-term persistence, and efficient homing to metastases. Remarkably, during concomitant vaccination over 3.5 years, the frequency of the pre-existing clone progressively increased, reaching up to 2.5% of the circulating CD8 pool while its effector functions were enhanced. In parallel, the disease stabilized, but subsequently progressed with loss of Melan-A expression by melanoma cells. Collectively, combined ex vivo analysis of T cell differentiation and clonality revealed for the first time a strong expansion of a tumor Ag-specific human T cell clone, comparable to protective virus-specific T cells. The observed successful boosting by peptide vaccination support further development of immunotherapy by including strategies to overcome immune escape.

Meidenbauer N, Zippelius A, Pittet MJ, Laumer M, Vogl S, Heymann J, Rehli M, Seliger B, Schwarz S, Le Gal FA, Dietrich PY, Andreesen R, Romero P, Mackensen A. · Department of Hematology/Oncology, University of Regensburg, Regensburg, Germany. · Cancer Res. · Pubmed #15342421 links to  free full text

Abstract: Tumor-reactive T cells play an important role in cancer immunosurveillance. Applying the multimer technology, we report here an unexpected high frequency of Melan-A-specific CTLs in a melanoma patient with progressive lymph node metastases, consisting of 18 and 12.8% of total peripheral blood and tumor-infiltrating CD8+ T cells, respectively. Melan-A-specific CTLs revealed a high cytolytic activity against allogeneic Melan-A-expressing target cells but failed to kill the autologous tumor cells. Loading of the tumor cells with Melan-A peptide reversed the resistance to killing, suggesting impaired function of the MHC class I antigen processing and presentation pathway. Mutations of the coding region of the HLA-A2 binding Melan-A26-35 peptide or down-regulation of the MHC class I heavy chain, the antigenic peptide TAP, and tapasin could be excluded. However, PCR and immunohistochemical analysis revealed a deficiency of the immunoproteasomes low molecular weight protein 2 and low molecular weight protein 7 in the primary tumor cells, which affects the quantity and quality of generated T-cell epitopes and might explain the resistance to killing. This is supported by our data, demonstrating that the resistance to killing can be partially reversed by pre-exposure of the tumor cells to IFN-gamma, which is known to induce the immunoproteasomes. Overall, this is the first report of an extremely high frequency of tumor-specific CTLs that exhibit competent T-cell-effector functions but fail to lyse the autologous tumor cells. Immunotherapeutic approaches should not only focus on the induction of a robust antitumor immune response, but should also have to target tumor immune escape mechanisms.

Dietrich PY, Le Gal FA, Dutoit V, Pittet MJ, Trautman L, Zippelius A, Cognet I, Widmer V, Walker PR, Michielin O, Guillaume P, Connerotte T, Jotereau F, Coulie PG, Romero P, Cerottini JC, Bonneville M, Valmori D. · Division of Oncology, Laboratory of Tumor Immunology, University Hospital, Geneva, Switzerland. · J Immunol. · Pubmed #12734356 links to  free full text

Abstract: The specificity of recognition of pMHC complexes by T lymphocytes is determined by the V regions of the TCR alpha- and beta-chains. Recent experimental evidence has suggested that Ag-specific TCR repertoires may exhibit a more V alpha- than V beta-restricted usage. Whether V alpha usage is narrowed during immune responses to Ag or if, on the contrary, restricted V alpha usage is already defined at the early stages of TCR repertoire selection, however, has remained unexplored. Here, we analyzed V and CDR3 TCR regions of single circulating naive T cells specifically detected ex vivo and isolated with HLA-A2/melan-A peptide multimers. Similarly to what was previously observed for melan-A-specific Ag-experienced T cells, we found a relatively wide V beta usage, but a preferential V alpha 2.1 usage. Restricted V alpha 2.1 usage was also found among single CD8(+) A2/melan-A multimer(+) thymocytes, indicating that V alpha-restricted selection takes place in the thymus. V alpha 2.1 usage, however, was independent from functional avidity of Ag recognition. Thus, interaction of the pMHC complex with selected V alpha-chains contributes to set the broad Ag specificity, as underlined by preferential binding of A2/melan-A multimers to V alpha 2.1-bearing TCRs, whereas functional outcomes result from the sum of these with other interactions between pMHC complex and TCR.

Dutoit V, Rubio-Godoy V, Pittet MJ, Zippelius A, Dietrich PY, Legal FA, Guillaume P, Romero P, Cerottini JC, Houghten RA, Pinilla C, Valmori D. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, University Hospital (CHUV), 1011 Lausanne, Switzerland. · J Exp Med. · Pubmed #12119345 links to  free full text

Abstract: In contrast with the low frequency of most single epitope reactive T cells in the preimmune repertoire, up to 1 of 1,000 naive CD8(+) T cells from A2(+) individuals specifically bind fluorescent A2/peptide multimers incorporating the A27L analogue of the immunodominant 26-35 peptide from the melanocyte differentiation and melanoma associated antigen Melan-A. This represents the only naive antigen-specific T cell repertoire accessible to direct analysis in humans up to date. To get insight into the molecular basis for the selection and maintenance of such an abundant repertoire, we analyzed the functional diversity of T cells composing this repertoire ex vivo at the clonal level. Surprisingly, we found a significant proportion of multimer(+) clonotypes that failed to recognize both Melan-A analogue and parental peptides in a functional assay but efficiently recognized peptides from proteins of self- or pathogen origin selected for their potential functional cross-reactivity with Melan-A. Consistent with these data, multimers incorporating some of the most frequently recognized peptides specifically stained a proportion of naive CD8(+) T cells similar to that observed with Melan-A multimers. Altogether these results indicate that the high frequency of Melan-A multimer(+) T cells can be explained by the existence of largely cross-reactive subsets of naive CD8(+) T cells displaying multiple specificities.

Valmori D, Dutoit V, Schnuriger V, Quiquerez AL, Pittet MJ, Guillaume P, Rubio-Godoy V, Walker PR, Rimoldi D, Liénard D, Cerottini JC, Romero P, Dietrich PY. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, and Multidisciplinary Oncology Center, University Hospital, Lausanne, Switzerland. · J Immunol. · Pubmed #11937585 links to  free full text

Abstract: Both the underlying molecular mechanisms and the kinetics of TCR repertoire selection following vaccination against tumor Ags in humans have remained largely unexplored. To gain insight into these questions, we performed a functional and structural longitudinal analysis of the TCR of circulating CD8(+) T cells specific for the HLA-A2-restricted immunodominant epitope from the melanocyte differentiation Ag Melan-A in a melanoma patient who developed a vigorous and sustained Ag-specific T cell response following vaccination with the corresponding synthetic peptide. We observed an increase in functional avidity of Ag recognition and in tumor reactivity in the postimmune Melan-A-specific populations as compared with the preimmune blood sample. Improved Ag recognition correlated with an increase in the t(1/2) of peptide/MHC interaction with the TCR as assessed by kinetic analysis of A2/Melan-A peptide multimer staining decay. Ex vivo analysis of the clonal composition of Melan-A-specific CD8(+) T cells at different time points during vaccination revealed that the response was the result of asynchronous expansion of several distinct T cell clones. Some of these T cell clones were also identified at a metastatic tumor site. Collectively, these data show that tumor peptide-driven immune stimulation leads to the selection of high-avidity T cell clones of increased tumor reactivity that independently evolve within oligoclonal populations.

Valmori D, Scheibenbogen C, Dutoit V, Nagorsen D, Asemissen AM, Rubio-Godoy V, Rimoldi D, Guillaume P, Romero P, Schadendorf D, Lipp M, Dietrich PY, Thiel E, Cerottini JC, Liénard D, Keilholz U. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, University Hospital, 1005 Lausanne, Switzerland. · Cancer Res. · Pubmed #11912149 links to  free full text

Abstract: To defend the host from malignancies, the immune system can spontaneously raise CD8(+) T-cell responses against tumor antigens. Investigating the functional state of tumor-reactive cytolytic T cells in cancer patients is a key step for understanding the role of these cells in tumor immunosurveillance and for evaluating the potential of immunotherapeutic approaches of vaccination against cancer. In this study we identified a subset of circulating tumor-reactive CD8(+) T lymphocytes, which specifically secreted IFN-gamma after exposition to autologous tumor cell lines in stage IV metastatic melanoma patients. Additional phenotypic characterization using multicolor flow cytometry revealed that a significant fraction of these cells were CD45RA(+)CCR7(-), a phenotype that has been proposed recently to characterize cytolytic effectors potentially able to home into inflamed tissues. In the case of an HLA-A2-expressing patient, the antigen specificity of this population was identified by using HLA-A2/peptide multimers incorporating a tyrosinase-derived peptide. Consistently with their phenotypic characteristics, A2/tyrosinase peptide multimer(+) CD8(+) T cells, isolated by cell sorting, were directly lytic ex vivo and able to specifically recognize tyrosinase-expressing tumor cells. Overall, these results provide the first evidence that a proportion of melanoma patients have circulating tumor-reactive T cells, which are lytic effectors cells.

Dutoit V, Rubio-Godoy V, Dietrich PY, Quiqueres AL, Schnuriger V, Rimoldi D, Liénard D, Speiser D, Guillaume P, Batard P, Cerottini JC, Romero P, Valmori D. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, Centre Hospitalier Universitaire Vaudois, Avenue Pierre-Decker, 1011 Lausanne, Switzerland. · Cancer Res. · Pubmed #11479225 links to  free full text

Abstract: MAGE-encoded antigens, which are expressed by tumors of many histological types but not in normal tissues, are suitable candidates for vaccine-based immunotherapy of cancers. Thus far, however, T-cell responses to MAGE antigens have been detected only occasionally in cancer patients. In contrast, by using HLA/peptide fluorescent tetramers, we have observed recently that CD8(+) T cells specific for peptide MAGE-A10(254-262) can be detected frequently in peptide-stimulated peripheral blood mononuclear cells from HLA-A2-expressing melanoma patients and healthy donors. On the basis of these results, antitumoral vaccination trials using peptide MAGE-A10(254-262) have been implemented recently. In the present study, we have characterized MAGE-A10(254-262)-specific CD8(+) T cells in polyclonal cultures and at the clonal level. The results indicate that the repertoire of MAGE-A10(254-262)-specific CD8(+) T cells is diverse both in terms of clonal composition, efficiency of peptide recognition, and tumor-specific lytic activity. Importantly, only CD8(+) T cells able to recognize the antigenic peptide with high efficiency are able to lyse MAGE-A10-expressing tumor cells. Under defined experimental conditions, the tetramer staining intensity exhibited by MAGE-A10(254-262)-specific CD8(+) T cells correlates with efficiency of peptide recognition so that "high" and "low" avidity cells can be separated by FACS. Altogether, the data reported here provide evidence for functional diversity of MAGE-A10(254-262)-specific T cells and will be instrumental for the monitoring of peptide MAGE-A10(254-262)-based clinical trials.

Dietrich PY, Walker PR, Quiquerez AL, Perrin G, Dutoit V, Liénard D, Guillaume P, Cerottini JC, Romero P, Valmori D. · Division of Oncology, University Hospital, Geneva, Switzerland. · Cancer Res. · Pubmed #11280765 links to  free full text

Abstract: HLA-A2+ melanoma patients develop naturally a strong CD8+ T cell response to a self-peptide derived from Melan-A. Here, we have used HLA-A2/peptide tetramers to isolate Melan-A-specific T cells from tumor-infiltrated lymph nodes of two HLA-A2+ melanoma patients and analyzed their TCR beta chain V segment and complementarity determining region 3 length and sequence. We found a broad diversity in Melan-A-specific immune T-cell receptor (TCR) repertoires in terms of both TCR beta chain variable gene segment usage and clonal composition. In addition, immune TCR repertoires selected in the patients were not overlapping. In contrast to previously characterized CD8+ T-cell responses to viral infections, this study provides evidence against usage of highly restricted TCR repertoire in the natural response to a self-differentiation tumor antigen.

Valmori D, Dutoit V, Liénard D, Lejeune F, Speiser D, Rimoldi D, Cerundolo V, Dietrich PY, Cerottini JC, Romero P. · Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, Lausanne Branch, University Hospital, Switzerland. · J Immunol. · Pubmed #10861093 links to  free full text

Abstract: The assessment of the TCR repertoire expressed by tumor-specific CD8+ T lymphocytes has been hampered to date by the difficulty of targeting the analysis to lymphocytes directed against a single epitope. In the present study we have used fluorescent A2/Melan-A tetramers in conjunction with anti-CD8 and anti-TCR beta-chain variable (BV) mAbs to analyze by flow cytometry the BV segment usage by Melan-A-specific CD8+ T cells in tumor-infiltrated lymph nodes (TILN) and tumor-infiltrating lymphocytes (TIL) from A2 melanoma patients. Analysis of TILN populations revealed small proportions of A2/Melan-A tetramer+ cells expressing many different BV together with over-representation of A2/Melan-A tetramer+ cells expressing certain BVs. The BV usage by A2/Melan-A tetramer+ lymphocytes in TIL was more restricted than that in TILN. Moreover, the predominant BV segments were quite distinct in populations derived from different patients. A2/Melan-A tetramer+ cells expressing the dominant BVs found in TILN could also be found in the corresponding peptide-stimulated autologous PBMC, although A2/Melan-A tetramer+ lymphocytes expressing additional BVs were also identified. Together, these results suggest that a large and diverse repertoire of Melan-A-specific T cells using different BV TCR segments is available in A2 melanoma patients.