Search results for "ACTIVATION"
showing 10 items of 2079 documents
Detailed characterization of human Mycobacterium tuberculosis specific HLA-E restricted CD8+TÂ cells
2018
HLA-E presented antigens are interesting targets for vaccination given HLA-Esâ essentially monomorphic nature. We have shown previously that Mycobacterium tuberculosis (Mtb) peptides are presented by HLA-E to CD8+effector TÂ cells, but the precise phenotype and functional capacity of these cells remains poorly characterized. We have developed and utilized in this study a new protocol combining HLA-E tetramer with intracellular staining for cytokines, transcription factors and cytotoxic molecules to characterize these cells in depth. We confirm in this study the significantly increased ex vivo frequency of Mtb-peptide/HLA-E-TM+CD8+TÂ cells in the circulation of patients with active tubercu…
Cutting edge: priming of CTL by transcutaneous peptide immunization with imiquimod.
2005
Abstract CTL are important in combating cancer and viruses. Therefore, triggering the complete potential of CTL effector functions by new vaccination strategies will not only improve prophylaxis of tumor or virus-related diseases, but also open opportunities for effective therapeutic immunizations. Using transcutaneous immunization, we show that epicutaneous (e.c.)4 application of an ointment containing a CTL epitope and the TLR7 ligand imiquimod is highly effective in activating T cells in mice using TCR-transgenic CTL or in wild-type mice. Transcutaneous immunization-activated CTL mount a full-blown immune response against the target epitope characterized by proliferation, cytolytic activ…
Generation of tumor-reactive CTL against the tumor-associated antigen HER2 using retrovirally transduced dendritic cells derived from CD34+ hemopoiet…
2000
Abstract Ag-specific CD8+ CTL are crucial for effective tumor rejection. Attempts to treat human malignancies by adoptive transfer of tumor-reactive CTL have been limited due to the difficulty of generating and expanding autologous CTL with defined Ag specificity. The current study examined whether human CTL can be generated against the tumor-associated Ag HER2 using autologous dendritic cells (DC) that had been genetically engineered to express HER2. DC progenitors were expanded by culturing CD34+ hemopoietic progenitor cells in the presence of the designer cytokine HyperIL-6. Proliferating precursor cells were infected by a retroviral vector encoding the HER2 Ag and further differentiated…
T cells engineered to express a T-cell receptor specific for glypican-3 to recognize and kill hepatoma cells in vitro and in mice
2015
Background & Aims Cancer therapies are being developed based on our ability to direct T cells against tumor antigens. Glypican-3 (GPC3) is expressed by 75% of all hepatocellular carcinomas (HCC), but not in healthy liver tissue or other organs. We aimed to generate T cells with GPC3-specific receptors that recognize HCC and used them to eliminate GPC3-expressing xenograft tumors grown from human HCC cells in mice. Methods We used mass spectrometry to obtain a comprehensive peptidome from GPC3-expressing hepatoma cells after immune-affinity purification of human leukocyte antigen (HLA)-A2 and bioinformatics to identify immunodominant peptides. To circumvent GPC3 tolerance resulting from feta…
Therapeutic afucosylated monoclonal antibody and bispecific T-cell engagers for T-cell acute lymphoblastic leukemia
2021
BackgroundT-cell acute lymphoblastic leukemia (T-ALL) is an aggressive disease with a poor cure rate for relapsed/resistant patients. Due to the lack of T-cell restricted targetable antigens, effective immune-therapeutics are not presently available and the treatment of chemo-refractory T-ALL is still an unmet clinical need. To develop novel immune-therapy for T-ALL, we generated an afucosylated monoclonal antibody (mAb) (ahuUMG1) and two different bispecific T-cell engagers (BTCEs) against UMG1, a unique CD43-epitope highly and selectively expressed by T-ALL cells from pediatric and adult patients.MethodsUMG1 expression was assessed by immunohistochemistry (IHC) on a wide panel of normal t…
Cytotoxic T cells with reciprocal antigenic peptide presentation function are not generally resistant to mutual lysis
2003
Cytotoxic T cells normally express major histocompatibility complex class I molecules, to which their T cell antigen receptors are restricted. Therefore, a single cytotoxic T cell can not only act as a cytolytic effector cell, but also as an antigen-presenting cell for other cytotoxic T cells of the same or a different clone. In the present paper, we used a murine cytotoxic T cell clone, 10BK.1, recognizing the ovalbumin-derived peptide OVA257-264 in combination with H-2Kb to investigate the consequences of reciprocal antigen presentation by these cytotoxic T cells. These cells proliferate after incubation with the relevant peptide in the absence of added accessory cells, indicating recipro…
Heat shock protein-antigen fusions lose their enhanced immunostimulatory capacity after endotoxin depletion.
2008
Heat shock proteins (HSPs) induce cross-presentation of antigens by dendritic cells (DC) as well as DC maturation. These properties make HSP antigen complexes good candidates to prime CD8 T cell responses against tumor-associated antigens. In this study, we analyzed four different members of the HSP70 family fused to a fragment of ovalbumin (OVA) as a model tumor antigen. E. coli-derived recombinant HSP70-OVA fusion proteins efficiently primed antigen-specific cytotoxic T cells in short-term in vivo immunization assays. Because of concerns that the adjuvant effect of HSPs may be due to endotoxin contamination, we studied this issue in detail. Induction of OVA-specific cytotoxicity was signi…
Combining dasatinib with dexamethasone long-term leads to maintenance of antiviral and antileukemia specific cytotoxic T cell responses in vitro
2012
Maintaining graft versus leukemia (GvL) and antivirus responses of cytotoxic T cells (CTLs) while suppressing graft-versus-host disease (GvHD) remains a challenge after allogeneic bone marrow transplantation. Clinical observations indicate that combining glucocorticoids with multi-tyrosine-kinase inhibitors could be a successful therapeutic approach. We and others have shown that the BCR-ABL/SRC kinase inhibitor dasatinib may enhance or suppress T cells in vitro. In this report, we evaluated combination effects of dasatinib and dexamethasone on CD3 + and virus-specific CD8 + T cells directly ex vivo and on antigen-specific leukemia-reactive and alloreactive CD8 + T cell clones. Functional o…
Lymphokine activated killer cells.
1989
Various subpopulations of human leukocytes may be induced by lymphokines to exert cytotoxic activity. In man major histocompatibility complex non-restricted tumor cell lysis by interleukin-2 (IL-2) induced peripheral blood lymphocytes is attributed mainly to natural killer cells. These T cell receptor negative large granular lymphocytes are called lymphokine activated killer (LAK) cells. In order to explore the potential of LAK cells in tumor therapy, several clinical studies have been conducted, using IL-2 alone or in combination with ex vivo IL-2-activated peripheral blood lymphocytes. Objective responses have reproducibly been achieved only in renal cell carcinoma and malignant melanoma …
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…