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In immunology, a naive T cell (T h 0 cell) is a T cell that has differentiated in the thymus, and successfully undergone the positive and negative processes of central selection in the thymus. Among these are the naive forms of helper T cells ( CD4 + ) and cytotoxic T cells ( CD8 + ).
V(D)J recombination (variable–diversity–joining rearrangement) is the mechanism of somatic recombination that occurs only in developing lymphocytes during the early stages of T and B cell maturation. It results in the highly diverse repertoire of antibodies/immunoglobulins and T cell receptors (TCRs) found in B cells and T cells, respectively.
Thus it may be possible, to take a large sample of cells from someones immune system, and look quickly at the range of sub-types present in the sample. The ability to obtain data quickly from tens or hundreds of thousands of cells, one cell at a time, should provide a good idea, of the size of the person's immune repertoire.
T cells' functional capacity is most influenced by aging effects. Age-related alterations are evident in all T-cell development stages, making them a significant factor in immunosenescence. [27] T-cell function decline begins with the progressive involution of the thymus, which is the organ essential
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.
Quiescence can prevent naive T cell activation after tonic signaling, meaning that T cells may be constitutively activated when not in the presence of a ligand. [21] After antigen exposure and costimulation, naive T cells start the process called quiescence exit, which results in proliferation and effector differentiation. [22]
CD2 was shown to prime naive T cells (T N) even without CD28 or TCR. [2] Also, CD27 is a receptor constitutively expressed on T N (its expression is downregulated upon TCR stimulation) and enhances T cell proliferation. [9] The differentiation of T helper cells (T H) into different subsets also partially depends on their co-stimulatory molecules.
Naive T cells, which are immature T cells that have yet to encounter an antigen, are converted into activated effector T cells after encountering antigen-presenting cells (APCs). These APCs, such as macrophages , dendritic cells , and B cells in some circumstances, load antigenic peptides onto the major histocompatibility complex (MHC) of the ...