Interleukins (ILs) are a group of cytokines that are expressed and secreted by white blood cells (leukocytes) as well as some other body cells. The human genome encodes more than 50 interleukins and related proteins.
Interleukin-2 (IL-2) is an interleukin, a type of cytokine signaling molecule in the immune system. It is a 15.5–16 kDa protein that regulates the activities of white blood cells (leukocytes, often lymphocytes) that are responsible for immunity. IL-2 is part of the body's natural response to microbial infection, and in discriminating between foreign ("non-self") and "self". IL-2 mediates its effects by binding to IL-2 receptors, which are expressed by lymphocytes. The major sources of IL-2 are activated CD4+ T cells and activated CD8+ T cells. Put shortly the function of IL-2 is to stimulate the growth of helper, cytotoxic and regulatory T cells.
Interleukin 3 (IL-3) is a protein that in humans is encoded by the IL3 gene localized on chromosome 5q31.1. Sometimes also called colony-stimulating factor, multi-CSF, mast cell growth factor, MULTI-CSF, MCGF; MGC79398, MGC79399: after removal of the signal peptide sequence, the mature protein contains 133 amino acids in its polypeptide chain. IL-3 is produced as a monomer by activated T cells, monocytes/macrophages and stroma cells. The major function of IL-3 cytokine is to regulate the concentrations of various blood-cell types. It induces proliferation and differentiation in both early pluripotent stem cells and committed progenitors. It also has many more specific effects like the regeneration of platelets and potentially aids in early antibody isotype switching.
Interleukin 5 (IL-5) is an interleukin produced by type-2 T helper cells and mast cells.
The common gamma chain (γc), also known as interleukin-2 receptor subunit gamma or IL-2RG, is a cytokine receptor sub-unit that is common to the receptor complexes for at least six different interleukin receptors: IL-2, IL-4, IL-7, IL-9, IL-15 and interleukin-21 receptor. The γc glycoprotein is a member of the type I cytokine receptor family expressed on most lymphocyte populations, and its gene is found on the X-chromosome of mammals.
The interleukin-2 receptor (IL-2R) is a heterotrimeric protein expressed on the surface of certain immune cells, such as lymphocytes, that binds and responds to a cytokine called IL-2.
Interleukin-15 (IL-15) is a protein that in humans is encoded by the IL15 gene. IL-15 is an inflammatory cytokine with structural similarity to Interleukin-2 (IL-2). Like IL-2, IL-15 binds to and signals through a complex composed of IL-2/IL-15 receptor beta chain (CD122) and the common gamma chain. IL-15 is secreted by mononuclear phagocytes following infection by virus(es). This cytokine induces the proliferation of natural killer cells, i.e. cells of the innate immune system whose principal role is to kill virally infected cells.
JAK1 is a human tyrosine kinase protein essential for signaling for certain type I and type II cytokines. It interacts with the common gamma chain (γc) of type I cytokine receptors, to elicit signals from the IL-2 receptor family, the IL-4 receptor family, the gp130 receptor family. It is also important for transducing a signal by type I (IFN-α/β) and type II (IFN-γ) interferons, and members of the IL-10 family via type II cytokine receptors. Jak1 plays a critical role in initiating responses to multiple major cytokine receptor families. Loss of Jak1 is lethal in neonatal mice, possibly due to difficulties suckling. Expression of JAK1 in cancer cells enables individual cells to contract, potentially allowing them to escape their tumor and metastasize to other parts of the body.
The interleukin 4 receptor is a type I cytokine receptor. It is a heterodimer, that is, composed of two subunits. IL4R is the human gene coding for IL-4Rα, the subunit which combines with either common gamma chain or with IL-13Rα1.
The interleukin-7 receptor is a protein found on the surface of cells. It is made up of two different smaller protein chains - i.e. it is a heterodimer, and consists of two subunits, interleukin-7 receptor-α (CD127) and common-γ chain receptor (CD132). The common-γ chain receptors is shared with various cytokines, including interleukin-2, -4, -9, and -15. Interleukin-7 receptor is expressed on various cell types, including naive and memory T cells and many others.
Interleukin-10 receptor subunit alpha is a subunit for the interleukin-10 receptor. IL10RA is its human gene.
Interleukin 1 receptor, type I (IL1R1) also known as CD121a, is an interleukin receptor. IL1R1 also denotes its human gene.
Interleukin 5 receptor, alpha (IL5RA) also known as CD125 is a subunit of the Interleukin-5 receptor. IL5RA also denotes its human gene.
Interleukin 15 receptor, alpha subunit is a subunit of the interleukin 15 receptor that in humans is encoded by the IL15RA gene.
Interleukin-2 receptor subunit beta is a protein that in humans is encoded by the IL2RB gene. Also known as CD122; IL15RB; P70-75.
Interleukin 20 receptor, beta subunit is a subunit of the interleukin-20 receptor and interleukin-22 receptor. It is believed to be involved in both pro-inflammatory and anti-inflammatory responses.
Interleukin 3 receptor, alpha (IL3RA), also known as CD123, is a human gene.
The interleukin-5 receptor is a type I cytokine receptor. It is a heterodimer of the interleukin 5 receptor alpha subunit and CSF2RB.
Interleukin 20 receptors (IL20R) belong to the IL-10 family. IL20R are involved in both pro-inflammatory and anti-inflammatory immune response. There are two types of IL20R: Type I and Type II.
The Interleukin-2 receptor alpha chain is a protein involved in the assembly of the high-affinity Interleukin-2 receptor, consisting of alpha (IL2RA), beta (IL2RB) and the common gamma chain (IL2RG). As the name indicates, this receptor interacts with Interleukin-2, a pleiotropic cytokine which plays an important role in immune homeostasis.
