Search results for "Positive"
showing 10 items of 1875 documents
A continuous infusion of a minor histocompatibility antigen-immunodominant peptide induces a delay of male skin graft rejection.
2009
Abstract We previously reported that an inhibition of antigen-specific Interferon-γ release and cytotoxicity occurs after a continuous infusion of an HY immunodominant peptide although this treatment is not able to cause a significant delay of male skin grafts rejection. In vivo administration of high doses of an HY peptide, through mini-osmotic pumps, in naive female mice was used to study the effects on the male skin grafts rejection. A continuous infusion of 1 mg of an HY peptide induces a significant delay of male skin graft rejection. In vitro HY-specific Interferon-γ release was inhibited adding peptide-specific suppressor cells: the ability to inhibit Interferon-γ release was evident…
The use of HLA-A*0201-transfected K562 as standard antigen-presenting cells for CD8+ T lymphocytes in IFN-γ ELISPOT assays
2001
ELISPOT assays are increasingly used for a direct detection and quantification of single antigen-specific T cells in freshly isolated peripheral blood mononuclear cells (PBMC). They are particularly attractive for the monitoring of specific T lymphocyte responses in clinical trials assessing antigen-specific immunizations in patients with cancer or chronic viral infections. However, one major limitation for the broad clinical implementation of ELISPOT assays is the lack of an inexhaustible source of suitable HLA-matched antigen-presenting cells (APC). Currently available allogeneic or xenogeneic APC (such as the human lymphoid hybrid T2 or HLA-transfected insect cells) can either lead to st…
Type I Interferon Protects Antiviral CD8+ T Cells from NK Cell Cytotoxicity
2014
Summary Despite development of new antiviral drugs, viral infections are still a major health problem. The most potent antiviral defense mechanism is the innate production of type I interferon (IFN-I), which not only limits virus replication but also promotes antiviral T cell immunity through mechanisms, which remain insufficiently studied. Using the murine lymphocytic choriomeningitis virus model system, we show here that IFN-I signaling on T cells prevented their rapid elimination in vivo. Microarray analyses uncovered that IFN-I triggered the expression of selected inhibitory NK-cell-receptor ligands. Consequently, T cell immunity of IFN-I receptor (IFNAR)-deficient T cells could be rest…
Induction of primary NY-ESO-1 immunity: CD8+ T lymphocyte and antibody responses in peptide-vaccinated patients with NY-ESO-1+ cancers
2000
Cancer–testis antigen NY-ESO-1 is one of the most immunogenic tumor antigens defined to date. Spontaneous humoral and CD8+ T-cell responses to NY-ESO-1 are detected in 40–50% of patients with advanced NY-ESO-1-expressing tumors. A clinical trial was initiated to study the immunological effects of intradermal vaccination with 3 HLA-A2-binding NY-ESO-1 peptides in 12 patients with metastatic NY-ESO-1-expressing cancers. Seven patients were NY-ESO-1 serum antibody negative, and five patients were NY-ESO-1 serum antibody positive at the outset of the study. Primary peptide-specific CD8+ T-cell reactions and delayed-type hypersensitivity responses were generated in four of seven NY-ESO-1 antibod…
Targeting Carcinoembryonic Antigen with DNA Vaccination: On-Target Adverse Events Link with Immunologic and Clinical Outcomes.
2015
Abstract Purpose: We have clinically evaluated a DNA fusion vaccine to target the HLA-A*0201–binding peptide CAP-1 from carcinoembryonic antigen (CEA605–613) linked to an immunostimulatory domain (DOM) from fragment C of tetanus toxin. Experimental Design: Twenty-seven patients with CEA-expressing carcinomas were recruited: 15 patients with measurable disease (arm-I) and 12 patients without radiological evidence of disease (arm-II). Six intramuscular vaccinations of naked DNA (1 mg/dose) were administered up to week 12. Clinical and immunologic follow-up was up to week 64 or clinical/radiological disease. Results: DOM-specific immune responses demonstrated successful vaccine delivery. All p…
Impact of antigen presentation on TCR modulation and cytokine release: implications for detection and sorting of antigen-specific CD8+ T cells using …
2002
Abstract Soluble MHC class I molecules loaded with antigenic peptides are available either to detect and to enumerate or, alternatively, to sort and expand MHC class I-restricted and peptide-reactive T cells. A defined number of MHC class I/peptide complexes can now be implemented to measure T cell responses induced upon Ag-specific stimulation, including CD3/CD8/ζ-chain down-regulation, pattern, and quantity of cytokine secretion. As a paradigm, we analyzed the reactivity of a Melan-A/MART-1-specific and HLA-A2-restricted CD8+ T cell clone to either soluble or solid-phase presented peptides, including the naturally processed and presented Melan-A/MART-1 peptide AAGIGILTV or the peptide ana…
Targeting positive regulatory domain I-binding factor 1 and X box-binding protein 1 transcription factors by multiple myeloma-reactive CTL.
2005
Abstract Growing evidence indicates that multiple myeloma (MM) and other malignancies are susceptible to CTL-based immune interventions. We studied whether transcription factors inherently involved in the terminal differentiation of mature B lymphocytes into malignant and nonmalignant plasma cells provide MM-associated CTL epitopes. HLA-A*0201 (A2.1) transgenic mice were used to identify A2.1-presented peptide Ag derived from the plasma cell-associated transcriptional regulators, positive regulatory domain I-binding factor 1 (PRDI-BF1) and X box-binding protein 1 (XBP-1). A2.1-restricted CTL specific for PRDI-BF1 and XBP-1 epitopes efficiently killed a variety of MM targets. PRDI-BF1- and X…
Cytotoxicity of tumor antigen specific human T cells is unimpaired by arginine depletion.
2013
Tumor-growth is often associated with the expansion of myeloid derived suppressor cells that lead to local or systemic arginine depletion via the enzyme arginase. It is generally assumed that this arginine deficiency induces a global shut-down of T cell activation with ensuing tumor immune escape. While the impact of arginine depletion on polyclonal T cell proliferation and cytokine secretion is well documented, its influence on chemotaxis, cytotoxicity and antigen specific activation of human T cells has not been demonstrated so far. We show here that chemotaxis and early calcium signaling of human T cells are unimpaired in the absence of arginine. We then analyzed CD8(+) T cell activation…
Understanding Factors Affecting Well-Being of Marginalized Populations in Different Cultural Contexts: Ethnic and National Identity of Roma Minority …
2018
This chapter focuses on the intersection of the third, fourth and tenth Sustainable Development Goals (SDGs), referring together to key pillars for improving social inclusion of vulnerable disadvantaged youth. Based on both Positive Youth Development approach and mutual intercultural relations perspective, it sets out to investigate developmental assets (such as ethnic and national identities), optimal outcomes (self-esteem), and their relations among Roma youth in six European countries (Albania, Bulgaria, the Czech Republic, Italy, Kosovo, and Romania). Among these countries, the Czech Republic was initially recognized as the more favorable context facilitating potential alignment of Roma…
Evaluation of the DNA microarray “AMR Direct Flow Chip Kit” for detection of antimicrobial resistance genes from Gram-positive and Gram-negative bact…
2019
Abstract Introduction The AMR Direct Flow Chip assay allows the simultaneous detection of a large variety of antibiotic resistance genetic markers. To assess this kit's performance, we use isolated colonies as starting material. The assay has been approved by the European Economic Area as a suitable device for in vitro diagnosis (CE IVD) using clinical specimens. Methods A total of 210 bacterial isolates harbouring either one or more antimicrobial resistance genes including plasmid-encoded extended-spectrum β-lactamases (SHV, CTX-M) and carbapenemases (GES, SME, KPC, NMC/IMI, SIM, GIM, SPM, NDM, VIM, IMP, and OXA), mecA, vanA and vanB, and 30 controls were included. Results The assay displa…