Search results
Results from the WOW.Com Content Network
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 can be recognized by a T-cell receptor. Specifically, the fragment, bound to the major histocompatibility ...
MHC-restricted antigen recognition, or MHC restriction, refers to the fact that a T cell can interact with a self-major histocompatibility complex molecule and a foreign peptide bound to it, but will only respond to the antigen when it is bound to a particular MHC molecule.
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.
The T cells selectively recognize the antigens; depending on the antigen and the type of the histocompatibility molecule, different types of T cells will be activated. For T-cell receptor (TCR) recognition, the peptide must be processed into small fragments inside the cell and presented by a major histocompatibility complex (MHC). [12]
T cell exhaustion can be triggered by several factors like persistent antigen exposure and lack of CD4 T cell help. [64] Antigen exposure also has effect on the course of exhaustion because longer exposure time and higher viral load increases the severity of T cell exhaustion. At least 2–4 weeks exposure is needed to establish exhaustion. [65]
This activation of naive T cell is controlled by a variety of signals: recognition of antigen in the form of a peptide: MHC complex on the surface of a specialized antigen-presenting cell delivers signal 1; interaction of co-stimulatory molecules on antigen-presenting cells with receptors on T cells delivers signal 2 (one notable example ...
Each B cell and T cell is specific for a particular antigen, which simply means that each of these cells is able to bind to a particular molecular structure (such as an antigen). The specificity of binding resides in a specific receptor for antigen: the B-cell receptor (BCR) and the T-cell receptor (TCR) for B and T cells, respectively. Both ...
T H 2 cells which produce IL-4, IL-5, and IL-13. A third category called T helper 17 cells (T H 17) were also discovered which are named after their secretion of Interleukin 17. CD8 + cytotoxic T-cells may also be categorized as: [5] T c 1 cells, T c 2 cells. Similarly to CD4 + T H cells, a third category called T C 17 were discovered that also ...