Search results for "T cell"
showing 10 items of 2228 documents
K Cell Activity of Normal and Chronic Lymphocytic Leukaemia Lymphocytes: Association with Lymphocytes bearing Receptors for Human C3b
1977
Surface properties of effector cells in antibody-dependent cell mediated cytotoxicity (ADCC) are at present under intensive investigation. Among these cells a lymphocyte population (K cells) has been described with receptors for the Fc portion of IgG (4), receptors for complement (11) and lacking receptors for sheep red blood cells (SRBC) and surface immunoglobulin (13). The purpose of the present study was to investigate more thoroughly the relationship between K cell activity in ADCC and cells bearing receptors for C3b and C3d.
Synthesis and biological evaluation of pyridinebetaine A and B
2009
The synthesis of the marine natural products pyridinebetaine A and B is reported. The biological evaluation of pyridinebetaine A and B and several analogues as cytotoxic, antifungal and antiviral agents is also described. Unfortunately, none of the compounds tested showed relevant antifungal or cytotoxic activity. Only pyridinebetaine B reduced the Herpes simplex virus type 1 virus replication, though only weakly.
Targeting p53, hdm2, and CD19: vaccination and immunologic strategies.
2000
Peptides presented by class I major histocompatibility complex (MHC) molecules and derived from normal self-proteins that are expressed at elevated levels by cells from a variety of human (Hu) malignancies provide, in theory, potential target antigens for a broad-spectrum, cytotoxic T lymphocyte (CTL)-based immunotherapy of cancer and hematologic malignancies. However, as such tumor- and leukemia-associated self-proteins are also expressed at low levels in some types of normal tissues, such as thymus, spleen and lymphohemopoietic cells, these self-MHC-self-peptide complexes may also represent thymic and/or peripheral tolerogens, thereby preventing immune responses. This is particularly true…
In vivo γδ T Cell Priming to Mycobacterial Antigens by Primary Mycobacterium tuberculosis Infection and Exposure to Nonpeptidic Ligands
1999
The recognition of phosphorylated nonpeptidic microbial metabolites by Vγ9Vδ2 T cells does not appear to require the presence of MHC molecules or antigen processing, permitting rapid responses against microbial pathogens. These may constitute an important area of natural anti-infectious immunity. To provide evidence of their involvement in immune reactivities against mycobacteria, we measured the responsiveness of peripheral blood Vγ9Vδ2 T cells in children with primary Mycobacterium tuberculosis (MTB) infections. Peripheral blood mononuclear cells from 22 children with MTB infections and 16 positivity of tuberculin (PPD)-negative healthy children were exposed to nonpeptidic antigens in vit…
Neutrophil extracellular traps arm DC vaccination against NPM-mutant myeloproliferation
2021
AbstractNeutrophil extracellular traps (NET) are web-like chromatin structures composed by dsDNA and histones, decorated with anti-microbial proteins. Their interaction with dendritic cells (DC) allows DC activation and maturation toward presentation of NET-associated antigens. Differently from other types of cell death that imply protein denaturation, NETosis preserves the proteins localized onto the DNA threads for proper enzymatic activity and conformational status, including immunogenic epitopes. Besides neutrophils, leukemic cells can release extracellular traps displaying leukemia-associated antigens, prototypically mutant nucleophosmin (NPMc+) that upon mutation translocates from nuc…
Differential requirements for antigen or homeostatic cytokines for proliferation and differentiation of human Vgamma9Vdelta2 naive, memory and effect…
2005
We have compared four human subsets of Vgamma9Vdelta2 T cells, naive (T(naive), CD45RA(+)CD27(+)), central memory (T(CM), CD45RA(-)CD27(+)), effector memory (T(EM), CD45RA(-)CD27(-)) and terminally differentiated (T(EMRA), CD45RA(+)CD27(-)), for their capacity to proliferate and differentiate in response to antigen or homeostatic cytokines. Cytokine responsiveness and IL-15R expression were low in T(naive) cells and progressively increased from T(CM) to T(EM) and T(EMRA) cells. In contrast, the capacity to expand in response to antigen or cytokine stimulation showed a reciprocal pattern and was associated with resistance to cell death and Bcl-2 expression. Whereas antigen-stimulated cells a…
Proteasome-inhibited dendritic cells demonstrate improved presentation of exogenous synthetic and natural HLA-class I peptide epitopes.
2004
The design and successful clinical implementation of cancer vaccines targeting the induction of T-cell mediated immunity is a rapidly evolving field that is hampered by an empirical selection of antigen and adjuvant. In particular, vaccines using defined tumor-associated peptide epitopes elicit only a restricted T-cell repertoire in a minority of patients. In this regard, vaccines comprising the whole spectrum of antigens presented by individual autologous tumors would be advantageous. In an in vitro model, we evaluated the capacity of naturally processed Epstein-Barr virus-transformed B-lymphoblastoid-cell line (LCL)-derived peptides to activate virus-specific CD8+ T cells of seropositive …
Separation of T-cell-stimulating activity from streptococcal M protein
1992
The superantigenic properties of M protein type 5 of Streptococcus pyogenes have been implicated as an important pathogenicity factor in streptococcal autoimmune diseases. Here we show that after a single purification step by affinity chromatography on immobilized albumin or fibrinogen, M protein has no mitogenic activity for T cells. We demonstrate that the superantigenicity of M proteins of type 5 and type 1 is due to contamination with the highly potent pyrogenic exotoxins of S. pyogenes in the range of 0.1 to 0.01%. These results raise a general caveat for work with these extremely active T-cell mitogens, because the mitogenicity of other streptococcal or staphylococcal proteins could b…
Stress protein/peptide complexes derived from autologous tumor tissue as tumor vaccines.
1999
Vaccination of inbred mice with tumor-derived stress proteins hsp70, hsp90, and gp96/grp94 elicits a protective immunity to the tumor from which the vaccine was purified. There is now comprehensive experimental evidence that the antigenicity of tumor-derived hsp70, hsp90, and gp96 preparations results from diverse arrays of endogenous peptide antigens complexed with these stress proteins. Vaccination with tumor-derived stress protein/peptide complexes leads to their uptake and processing by professional antigen-presenting cells and to presentation of associated tumor peptide antigens to cytotoxic T cells. This induces a tumor-specific cytotoxic T cell response. The attractiveness of the con…
The enemy in you: the interdependency of the localisation and antigenicity of proteins
2009
The subcellular localisation of protein components should be important for their antigenicity. This assumption is derived from the concept of MHC restriction, where CD4 and CD8 T lymphocytes can only interact with MHC II and MHC I surface receptors, respectively. If this mechanism applies, however, then intracellular components should have immunogenic effects mediated by MHC II and CD4 T lymphocytes as soon as they enter the extracellular space. Conversely, extracellular components should generate an immune response that is mediated by MHC I and CD8 lymphocytes when they breach the intracellular space and when they exceed a critical concentration. In this study, these hypotheses were invest…