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Antigen presentation stimulates immature T cells to become either mature "cytotoxic" CD8+ cells or mature "helper" CD4+ cells. An antigen-presenting cell (APC) or accessory cell is a cell that displays an antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation.
Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells. Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces, antigen processing must occur before the antigen fragment ...
It is in this way, the MHC class I-dependent pathway of antigen presentation, that the virus infected cells signal T-cells that abnormal proteins are being produced as a result of infection. The fate of the virus-infected cell is almost always induction of apoptosis through cell-mediated immunity, reducing the risk of infecting neighboring ...
Cross-presentation is the ability of certain professional antigen-presenting cells (mostly dendritic cells) to take up, process and present extracellular antigens with MHC class I molecules to CD8 T cells (cytotoxic T cells).
The discussion that follows now concerns alpha/beta T cells. The TCR (of αβ T-cells) binds a bimolecular complex displayed at the surface of some other cells called an antigen-presenting cell (APC). This complex consists of: a fragment of an antigen lying within the groove of a histocompatibility molecule. The complex has been compared to a ...
T cells require two signals to become fully activated. A first signal, which is antigen-specific, is provided through the T cell receptor (TCR) which interacts with peptide-MHC molecules on the membrane of an antigen presenting cell (APC). A second signal, the co-stimulatory signal, is antigen nonspecific and is provided by the interaction ...
It is unclear how exactly having the HLA-B27 tissue type increases the risk of ankylosing spondylitis and other associated inflammatory diseases, but mechanisms involving aberrant antigen presentation or T cell activation have been hypothesized. Tissue allorecognition: MHC molecules in complex with peptide epitopes are essentially ligands for TCRs.
These molecules are constitutively expressed in professional, immune antigen-presenting cells, but may also be induced on other cells by interferon γ. [4] They are expressed on the epithelial cells in the thymus and on APCs in the periphery. MHC class II expression is closely regulated in APCs by CIITA, which is the MHC class II transactivator ...