Cytotoxic T cell

A recent example of a CA model of the immune response in AIDS is Pandley s four-cell model using interactions among macrophages (= M) containing parts of the virus on their surface, helper T cells (= H), cytotoxic T cells (= C) and the virus (= V) ([pand89], [pandQl]) ... 

COPD is a chronic inflammatory disease that results from prolonged and repeated inhalation of particles and gases, chronic (or latent) infection or an interaction of these factors. In many cases, the inflammation persists even when the exposure (in most cases smoking) is stopped. Prominent among the infiltrating leukocytes are neutrophils, CD8+ lymphocytes (Co-receptor for the T-cell receptor. CD8+ is specific for the class IMHC protein. It is expressed on the surface of cytotoxic T-cells and natural killer cells.) and CD68+ monocytic cells (A lysosomal antigen. All cells that rich in... 

The field of DNA vaccination started when eukaryotic expression vectors were injected into the muscle of laboratory animals [2]. The authors observed protein expression for more than 2 months after injection and noted that no special delivery system was required to obtain this expression. Subsequently, it was demonstrated that antibodies can be induced simply by injecting plasmid DNA into the muscle of mice [3]. Subsequent studies found that the injection of expression plasmids also leads to the induction of a cytotoxic T-cell response. After injection, the DNA enters cells of the vaccinated host and the encoded gene becomes expressed. This eventually leads to the induction of a cellular cytotoxic T-cell, T-helper, and/or humoral (antibody) immune response. 

Large granular lymphocytes, not belonging to either the T- or B-cell lineage. Natural killer (NK) cells are considered part of the innate defense system since, in contrast to cytotoxic T-cells, they are able to kill certain tumor cells in vitro without prior sensitization. The basal activity of NIC cells increases dramatically following stimulation with type I IFNs. In addition, NK cells display Fc-receptors for IgG and are important mediators of Antibody-Dependent-Cell-mediated-Cytotoxicity (ADCC). 

Cytotoxic Agents Cytotoxic T-cells Danaparoid (Heparinoid)... 

Class I. These molecules are expressed on the surfaces of all nucleated cells and are recognized by CD8+ cells, also known as cytotoxic T cells. There are three subclasses of MHC class I molecules called HLA-A, HLA-B, and HLA-C. 

Cytotoxic T cells (CD8+) promote target-cell destruction by activating cellular apoptosis or aggressively killing the target cell via the release of cytotoxic proteins. 

Helper T cells (CD4+) are the great communicators of the immune response. Once activated, they proliferate and secrete cytokines that regulate effector cell function. Some helper T cells secrete cytokines that recruit cytotoxic T cells, B cells, or APCs, whereas others secrete cytokines that turn off the immune response once an antigen has been destroyed. 

After activation, cytotoxic T cells emerge from lymphoid organs to infiltrate the graft and trigger the immune response. These cells have been shown to induce graft destruction via two mechanisms (1) secretion of the cytotoxic proteins perforin and granzyme B, and (2) induction of cellular apoptosis... 

In spite of having no intrinsic catalytic domains, activation of T lymphocytes commences with tyrosine phosphorylations, activation of PLC-v with production of IP3 and DAG, and elevation of cytosolic free Ca2+. Thus, the consequences of receptor ligation are not dissimilar from those induced by the receptors for EGF or PDGF. An early study trying to explain the induction of tyrosine kinase activity resulted in the discovery of the nonreceptor protein tyrosine kinase Lck (p56lck), a T-cell-specific member of the Src family. Lck is associated with the cytosolic tail of CD4 (in helper T cells) or CD8 (in cytotoxic T cells) (Figure 8.14). As mentioned, the extracellular domains of these... 

Cytotoxic T cells may play a role in inducing direct destruction of cancer cells, in particular those transformed by viral infection (and who express viral antigen on their surface). In vitro studies have shown that cytotoxic T-lymphocytes obtained from the blood of persons suffering from various cancer types are capable of destroying those cancer cells. 

IL-2-stimulated cytotoxic T cells appear even more efficacious than LAK cells in promoting tumour regression. The approach adopted here entails removal of a tumour biopsy, followed by isolation of T-lymphocytes present within the tumour. These tumour-infiltrating lymphocytes (TILs) are cytotoxic T-lymphocytes that apparently display a cell surface receptor which specifically binds the tumour antigen in question. They are thus tumour-specific cells. Further activation of these TILs by in vitro culturing in the presence of IL-2, followed by reintroduction into the patient along with IL-2, promoted partial/full tumour regression in well over 50 per cent of treated patients. 

Wanschitz, J., Maier, H., Lassmann, H., Budka, H. and Berger, T. Distinct time pattern of complement activation and cytotoxic T cell response in Guillain-Barre syndrome. Brain 126 2034-2042, 2003. 

It is also more or less accepted that T-cells, in particular T-helper cells (CD4+), may develop into either Thl cells or Th2 cells. By doing so, T-helper cells orchestrate the ensuing immune response by the types of cytokines they produce. Thl cells, by producing IL-12 and y-IFN, stimulate macrophages and/or cytotoxic T-cells to kill and destroy infected or malignant cells, or to initiate a delayed type hypersensitivity (DTH) reaction Th2 cells, by producing IL-4, IL-5, IL-10, IL-13, trigger B-cells to initiate antibody production. 

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