Search results for "Cytotoxic"
showing 10 items of 1673 documents
Highly protective in vivo function of cytomegalovirus IE1 epitope-specific memory CD8 T cells purified by T-cell receptor-based cell sorting.
2005
ABSTRACTReconstitution of antiviral CD8 T cells is essential for controlling cytomegalovirus (CMV) infection after bone marrow transplantation. Accordingly, polyclonal CD8 T cells derived from BALB/c mice infected with murine CMV protect immunocompromised adoptive transfer recipients against CMV disease. The protective population comprises CD8 T cells with T-cell receptors (TCRs) specific for defined and for as-yet-unknown viral epitopes, as well as a majority of nonprotective cells with unrelated specificities. Defined epitopes include IE1/m123 and m164, which are immunodominant in terms of the magnitude of the CD8 T-cell response, and a panel of subordinate epitopes (m04, m18, M45, M83, a…
Phenotype, Function, and Safety of a p53 TCR Bicistronic GMP-Suitable Retroviral Construct.
2006
Abstract Malignant transformation of normal cells is frequently correlated with the involvement of so called tumor-associated antigens (TAA). Such proteins, that are often overexpressed in tumor cells, can be recognized by cytotoxic CD8+ T cells (CTL) if presented as peptides on MHC (Major-Histocompatibility-Complex)-class I molecules. Due to self-tolerance mechanisms, the peripheral T cell repertoire is devoid of efficient TAA-specific, tumor-reactive CTL with high affinity, limiting the successful development of antigen-specific immunotherapeutic strategies based on such tumor-reactive T cells. The aim of this project is the preclinical development of an adoptive immunotherapy against p53…
p53 Immunotherapy of Cancer
2012
Mutation and overexpression of the p53 tumor suppressor protein are the most common genetic alterations in human cancers. Peptides derived from non-mutated (wild type, wt) and mutated p53-molecules, processed and presented in the context of major histocompatibility complex (MHC) molecules by tumor cells for T-cell recognition, could serve as broad targets for cancer immunotherapy. Isolating p53-reactive T lymphocytes in healthy donors or patients has been hampered by the fact that most individuals display a peripheral p53-reactive T-cell repertoire that is devoid of high-avidity MHC class I-restricted cytotoxic T lymphocytes (CTL). Only low-avidity T lymphocytes are left due to self-toleran…
Redirected EBV-Specific Stem Cell-Memory and Central-Memory CD8+ T Lymphocytes Exhibit Effective and Sustained Antileukemic Immunity to Acute Myeloid…
2014
Abstract Introduction: Adoptive cellular therapy (ACT) of donor-derived cytolytic T lymphocytes (CTL) directed to leukemia or herpesvirus has proven promising to improve antiviral and antileukemic immunity in patients following allogeneic hematopoietic stem cell transplantation (AHSCT). However, durable clinical responses are often hampered by detrimental graft-versus host (GvH) reactivity and limited persistence of transferred, fully differentiated antileukemic effector T cells (TEFF). We thus explored memory and tumoricidal features of in vitro generated EBV-specific stem cell-memory T cells (TSCM) and central-memory T (TCM) cells, T cell-receptor (TCR) redirected to primary acute myeloid…
Melanomas resist T-cell therapy through inflammation-induced reversible dedifferentiation.
2012
Adoptive cell transfer therapies (ACTs) with cytotoxic T cells that target melanocytic antigens can achieve remissions in patients with metastatic melanomas, but tumours frequently relapse. Hypotheses explaining the acquired resistance to ACTs include the selection of antigen-deficient tumour cell variants and the induction of T-cell tolerance. However, the lack of appropriate experimental melanoma models has so far impeded clear insights into the underlying mechanisms. Here we establish an effective ACT protocol in a genetically engineered mouse melanoma model that recapitulates tumour regression, remission and relapse as seen in patients. We report the unexpected observation that melanoma…
Therapeutic Vaccination of Hematopoietic Cell Transplantation Recipients Improves Protective CD8 T-Cell Immunotherapy of Cytomegalovirus Infection
2021
Reactivation of latent cytomegalovirus (CMV) endangers the therapeutic success of hematopoietic cell transplantation (HCT) in tumor patients due to cytopathogenic virus spread that leads to organ manifestations of CMV disease, to interstitial pneumonia in particular. In cases of virus variants that are refractory to standard antiviral pharmacotherapy, immunotherapy by adoptive cell transfer (ACT) of virus-specific CD8+ T cells is the last resort to bridge the “protection gap” between hematoablative conditioning for HCT and endogenous reconstitution of antiviral immunity. We have used the well-established mouse model of CD8+ T-cell immunotherapy by ACT in a setting of experimental HCT and mu…
TH17 cells mediate pulmonary collateral priming
2010
Background Our laboratory has shown that inhalational sensitization to new antigens is facilitated through an ongoing T H 2-polarized inflammation of the lung, a phenomenon we call "collateral priming." Objective We were interested to analyze whether a T H 1-polarized pulmonary inflammation also facilitates priming toward new antigens and which cytokine or cytokines are involved. Methods T H 1-polarized T cells were generated in vitro and transferred into congenic mice. Mice were challenged initially with cognate antigen and an unrelated antigen; consecutively, they received cognate antigen or the secondary antigen. Airway inflammation, antigen-specific IgG2a levels, and airway hyperrespons…
Interferon-Beta Therapy of Multiple Sclerosis Patients Improves the Responsiveness of T Cells for Immune Suppression by Regulatory T Cells
2015
Multiple sclerosis (MS) is an inflammatory autoimmune disease characterized by imbalanced immune regulatory networks, and MS patient-derived T effector cells are inefficiently suppressed through regulatory T cells (Treg), a phenomenon known as Treg resistance. In the current study we investigated T cell function in MS patients before and after interferon-beta therapy. We compared cytokine profile, responsiveness for Treg-mediated suppression ex vivo and evaluated reactivity of T cells in vivo using a humanized mouse model. We found that CD4+ and CD8+ T cells of therapy-naive MS patients were resistant to Treg-mediated suppression. Treg resistance is associated with an augmented IL-6 product…
A double-negative (IgD−CD27−) B cell population is increased in the peripheral blood of elderly people
2009
The T cell branch of the immune system has been extensively studied in the elderly and it is known that the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the present paper, we describe the IgD(-)CD27(-) double-negative B cell population which (as we have recently described) is higher in the elderly. Most of these cells were IgG(+). Evaluation of the telomere length and expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the markers of memory B cells. We also show that these cells do not act as antigen…
T cell receptor gene rearrangements of T lymphocytes infiltrating the liver in chronic active hepatitis B and primary biliary cirrhosis (PBC): Oligoc…
1990
Immunological events are involved in the pathophysiology of chronic active hepatitis as indicated from the accumulation of T lymphocytes at the site of tissue damage. We generated T cell clones from liver biopsies of 3 patients with chronic active hepatitis B and 2 patients with primary biliary cirrhosis. These T cell clones (n = 84) were analyzed by means of T cell receptor (TcR) beta gene rearrangements to determine whether the infiltrate consists of a polyclonal or oligoclonal T cell population. The vast majority (62 of 64) of T cell clones from three different patients with chronic active hepatitis B showed no identical rearrangements of the TcR beta chain genes. In marked contrast, in …