Search results
Results from the WOW.Com Content Network
T cells are one of the important types of white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface. T cells are born from hematopoietic stem cells, [1] found in the bone marrow.
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]
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 ...
T cells that bind (via their T cell receptor) to self antigen (presented by dendritic cells on MHC molecules) too strongly are induced to die. The second type of immunological tolerance is peripheral tolerance. Some self reactive T cells escape the thymus for a number of reasons, mainly due to the lack of expression of some self antigens in the ...
The ability of T cells to recognize foreign antigens is mediated by the T cell receptor (TCR), which is a surface protein able to recognize short protein sequences that are presented on MHC. The purpose of thymocyte development is to produce mature T cells with a diverse array of functional T cell receptors, through the process of TCR gene ...
This verification step is a protective measure to ensure that a T cell is responding to a foreign antigen. If this second signal is not present during initial antigen exposure, the T cell presumes that it is auto-reactive. This results in the cell becoming anergic (anergy is generated from the unprotected biochemical changes of Signal 1 ...
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 ...
Later studies revealed that tissue rejection due to incompatibility is only a facet of the full function of MHC molecules, which is to bind an antigen derived from self-proteins, or from pathogens, and bring the antigen presentation to the cell surface for recognition by the appropriate T-cells. [2]