1980
Natural killer T (NKT) cells are a heterogeneous group of T cells that share properties of both T cells and natural killer cells.
Such NKT cells recognize the CD1d molecule, an antigen-presenting molecule that binds self and foreign lipids and glycolipids.
They constitute approximately 0.1% of all peripheral blood T cells.
Natural killer T cells should not be confused with natural killer cells.
NKT cells are ref2242ed to as CD1d-restricted T cells, some of which coexpress a semi-invariant T-cell receptor and NK cell markers.
Higher levels of invariant NKT cells in cancer patients is associated with a longer life than those with lower levels of cells.
NKT cells are a subset of T cells that coexpress an αβ T-cell receptor.
NKT cells also express a variety of molecular markers that are typically associated with NK cells, such as NK1.1.
The best-known NKT cells invariant’ or ‘type 1′ NKT, differ from conventional αβ T cells in that their T-cell receptors are far more limited in diversity.
Type1 NKT and other CD1d-restricted T cells known as type 2’ NKT, recognize lipids and glycolipids presented by CD1d molecules.
NKT cells are important in recognizing glycolipids from organisms such as Mycobacterium.
NKT cells include: NK1.1+ and NK1.1−, as well as CD4+, CD4−, CD8+ and CD8− cells.
Natural killer T cells can share other features with NK cells, as well, such as CD16 and CD56 expression.
Invariant natural killer T (iNKT) cells express high levels of transcriptional regulator promyelocytic leukemia zinc finger for their development.
Natural killer T cells are most commonly found in the liver, but are also found in the thymus, spleen, peripheral blood, bone marrow and fat tissue.
There are fewer iNKT cells circulating .
There are five major distinct iNKT cell subsets, which produce a different set of cytokines once activated.
Activated iNKT cells can impact immune responses, by engaging in cross talk with other immune cells, like dendritic cells, neutrophils and lymphocytes.
Activation occurs by engagement with their invariant T cell receptor, and can also be indirectly activated through cytokine signaling.
iNKT cells are not very numerous, but they are known to play a role in chronic inflammatory diseases like autoimmune disease, asthma and metabolic syndrome.
In human autoimmune diseases, iNKT numbers are decreased in peripheral blood.
NKT on activation are able to produce interferon gamma, IL-4, and granulocyte-macrophage colony-stimulating factor, as well as multiple other cytokines and chemokines to include IL-2, Interleukin-13, Interleukin-17, Interleukin-21, and TNF-alpha.
Natural Killer T cells recognize protected microbial lipid agents which are presented by CD1d-expressing antigen presenting cells to fight against infections and enhance the humoral immunity.
The NKT cells provide support and help to B cells which act as a microbial defense and aid in targeting for B-cell vaccines.
NKT cell dysfunction or deficiency has been shown to lead to the development of autoimmune diseases,such as diabetes or atherosclerosis and cancers.
NKT cells are implicated in the disease progression of human asthma.
NKT cells have rapid release of cytokines (such as IL-2, IFN-gamma, TNF-alpha, and IL-4) that promote or suppress different immune responses.
NKT cells are a subset of T cells that coexpress an αβ T-cell receptor, but also express molecular markers that are typically associated with NK cells, such as NK1.1.
NKT cells are important in recognizing glycolipids from organisms such as Mycobacterium, which causes tuberculosis.
NKT cells include both NK1.1+ and NK1.1−, as well as CD4+, CD4−, CD8+ and CD8− cells.
Natural killer T cells can share other features with NK cells, as well, such as CD16 and CD56 expression.
The best-known subset of CD1d-dependent NKT cells is expressed as an invariant T-cell receptor (TCR) α chain.
Invariant NKT cells (iNKT) cells are notable for their ability to respond rapidly to danger signals and pro-inflammatory cytokines.
Activated Invariant NKT cells (iNKT) engage in effector functions, like NK transactivation, T cell activation and differentiation, B cell activation, dendritic cell activation and cross-presentation activity, and macrophage activation.
iNKT cells recognize lipid antigens on CD1d, a non-polymorphic major histocompatibility complex class I-like antigen presenting molecule.
There are five major distinct iNKT cell subsets producing a different set of cytokines once activated.
The subtypes vary in cytokine production, T-follicular helper-like function and Il-10 dependent regulatory functions.
Subtypes of iNKT engage in cross talk with other immune cells, like dendritic cells, neutrophils and lymphocytes.
Activation occurs by engagement with their T cell receptor, and can also be indirectly activated through cytokine signaling.
iNKT cells play a role in chronic inflammatory diseases like autoimmune disease, asthma and metabolic syndrome.
iNKT cell numbers are decreased in peripheral blood in autoimmune diseases.
NKT cells are able to produce large quantities of interferon gamma, IL-4, and granulocyte-macrophage colony-stimulating factor, as well as multiple other cytokines and chemokines, such as IL-2, Interleukin-13, Interleukin-17, Interleukin-21, and TNF-alpha.
Natural Killer T (NKT) cells recognize microbial lipid agents which are presented by CD1d-expressing antigen presenting cells.
NKT cells fight against infections and enhance the humoral immunity.
NKT cells provide support and help to B cells which act as a microbial defense and aid in targeting for B-cell vaccines.
NKT cells seem to be essential for several aspects of immunity because
The dysfunction or deficiency of NKT cells can lead to the development of autoimmune diseases, cancers and asthma.
NKT cells may rapidly release cytokines IL-2, IFN-gamma, TNF-alpha, and IL-4 that promote or suppress different immune responses.