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  • 1
    Keywords: PEPTIDE ; CANCER ; CELLS ; BLOOD ; CELL ; CLINICAL-TRIAL ; COMBINATION ; NEW-YORK ; DISTINCT ; SAMPLE ; SAMPLES ; RESPONSES ; BASE ; CD8(+) T-CELLS ; T cell ; T cells ; T-CELL ; T-CELLS ; ASSOCIATION ; TRIAL ; TRIALS ; IDENTIFICATION ; ASSAY ; NUMBER ; CLINICAL-TRIALS ; COUNTRIES ; MELANOMA ; LYMPHOCYTES ; VARIABILITY ; PEPTIDES ; NETHERLANDS ; CD8(+) ; ELISPOT ; IMMUNOTHERAPY ; T-LYMPHOCYTES ; T lymphocyte ; sensitivity ; PERIPHERAL-BLOOD ; PROJECT ; INTERFERON-GAMMA ; tetramer ; T lymphocytes ; GUIDELINES ; HETEROGENEITY ; CANCER VACCINES ; ONCOLOGY ; monitoring ; INCREASE ; analysis ; methods ; ASSAYS ; PHASE ; technique ; USA ; RECOMMENDATIONS ; STANDARDIZATION ; VARIABLES ; immunology ; INCREASES ; clinical trial ; CELL RESPONSES ; IMPORTANT DETERMINANT ; CD4+T-CELL IMMUNITY ; CYTOKINE FLOW-CYTOMETRY ; GAMMA ELISPOT ASSAYS ; Interlaboratory testing
    Abstract: The interpretation of the results obtained from immunomonitoring of clinical trials is a difficult task due to the variety of methods and protocols available to detect vaccine-specific T-cell responses. This heterogeneity as well as the lack of standards has led to significant scepticism towards published results. In February 2005, a working group was therefore founded under the aegis of the Association for Immunotherapy of Cancer ("CIMT") in order to compare techniques and protocols applied for the enumeration of antigen-specific T-cell responses. Here we present the results from two consecutive phases of an international inter-laboratory testing project referred to as the "CIMT monitoring panel". A total of 13 centers from six European countries participated in the study in which pre-tested PBMC samples, synthetic peptides and PE-conjugated HLA-tetramers were prepared centrally and distributed to participants. All were asked to determine the number of antigen-specific T-cells in each sample using tetramer staining and one functional assay. The results of the first testing round revealed that the total number of cells analyzed was the most important determinant for the sensitive detection of antigen-specific CD8(+) T-cells by tetramer staining. Analysis by ELISPOT was influenced by a combination of cell number and a resting phase after thawing of peripheral blood mononuclear cells. Therefore, the experiments were repeated in a second phase but now the participants were asked to change their protocols according to the new guidelines distilled from the results of the first phase. The recommendations improved the number of antigen-specific T-cell responses that were detected and decreased the variability between the laboratories. We conclude that a two-step approach in inter-laboratory testing allows the identification of distinct variables that influence the sensitivity of different T-cell assays and to formally show that a defined correction to the protocols successfully increases the sensitivity and reduces the inter-center variability. Such "two-step" inter-laboratory projects could define rational bases for accepted international guidelines and thereby lead to the harmonization of the techniques used for immune monitoring
    Type of Publication: Journal article published
    PubMed ID: 17721783
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  • 2
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Allogeneic bone marrow transplantation (BMT) is a potentially curative therapy for patients with haematologic malignancies. Several lines of evidence demonstrate that donor T cells are involved in the antitumour effects observed after BMT. Thus, patients receiving T-cell-depleted BMT have a higher risk of leukaemia relapse compared to patients receiving nonmanipulated BMT, and patients experiencing graft-versus-host disease (GVHD) have a lower risk of disease relapse than patients who do not experience GVHD. Although the importance of donor T cells for the curative action of BMT has been established, the exact mechanisms and molecules involved in this graft-versus-tumour effect remain largely unknown. In a recently initiated project, we have conducted a longitudinal study of T-cell clonotypes in patients who received peripheral blood stem cell grafts after nonmyeloablative conditioning. Peripheral blood samples were obtained sequentially after transplant, and the mononuclear cells (MNCs) were isolated and cryopreserved. CD8+ T cells were isolated from the MNCs by use of immunomagnetic beads or FACS and analysed for the presence of clonally expanded cells by T-cell receptor clonotype mapping based on RT-PCR and denaturing gradient gel electrophoresis (DGGE). Using this gel-based methodology, clonally expanded T cells were monitored after transplant and compared to the clinical data of the patients. The preliminary results demonstrates the presence of clonally expanded CD8+ T cells at all time points analysed. Furthermore, a number of clonotypes persisted for more than 6 months, and other clonotypes emerged during this period. The appearance of newly emerged clonotypes which coincided with clinical GVHD could indicate a role for these T cells in the pathogenesis of GVHD.
    Type of Medium: Electronic Resource
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