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All T cells derive from progenitor cells in the bone marrow, which become committed to their lineage in the thymus.All T cells begin as CD4-CD8-TCR- cells at the DN (double-negative) stage, where an individual cell will rearrange its T cell receptor genes to form a unique, functional molecule, which they, in turn, test against cells in the thymic cortex for a minimal level of interaction with ...
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.
It exposes T cells to normal, healthy proteins from all parts of the body, and T cells that react to those proteins are destroyed. Each T cell recognizes a specific antigen when it is presented in complex with a major histocompatibility complex (MHC) molecule by an antigen presenting cell .
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 rearrangement. Unlike most genes, which have a stable sequence in each cell which expresses them, the T cell receptor is made up of a series of alternative gene fragments. In order to create a ...
Once mature, T cells emigrate from the thymus to provide vital functions in the immune system. [11] [12] Each T cell has a distinct T cell receptor, suited to a specific substance, called an antigen. [12] Most T cell receptors bind to the major histocompatibility complex on cells of the body.
Antigen transfer in the thymus is the transmission of self-antigens between thymic antigen-presenting cells which contributes to the establishment of T cell central tolerance. [ 1 ] Thymus represents an origin of T cell development and its responsibility is to select functional but also safe T cells which will not attack self tissues.
Development of T cell progenitors [14] [15] [16] T cell precursors originate from bone marrow (BM). Population of the earliest hematopoietic progenitors do not bear markers of differentiated cells (for that they are called Lin- „lineage negative“) but express molecules such as SCA1 (stem cell antigen) and KIT (receptor for stem cell factor ...
Foxp3 is a specific marker of natural T regulatory cells (nTregs, a lineage of T cells) and adaptive/induced T regulatory cells (a/iTregs), also identified by other less specific markers such as CD25 or CD45RB. [6] [7] [8] In animal studies, Tregs that express Foxp3 are critical in the transfer of immune tolerance, especially self-tolerance. [13]