XCL1

XCL1 (or X-C motif chemokine ligand 1) is a small cytokine belonging to the XC chemokine family. It is also known as lymphotactin-α and small-inducible cytokine B9. XCL1 is secreted by T cells and NK cells and has functions primarily in the immune system.

Structure

XCL1 is a protein that is encoded by the XCL1 gene in humans. It is a monomeric peptide of approximately 8-10 kilodaltons in size. Unlike most other chemokines, XCL1 only has two of the four conserved cysteine residues that are characteristic of the chemokine family.

Function

XCL1 is secreted by activated T cells and NK cells and is chemotactic for monocytes and dendritic cells. It functions by binding to the receptor XCR1, which is expressed on the surface of these cells. This binding triggers a series of intracellular signaling events that lead to cell migration and other responses.

XCL1 also has antimicrobial activity and can directly kill certain types of bacteria and fungi. This is thought to be due to its ability to disrupt the integrity of microbial cell membranes.

Clinical significance

Alterations in the expression or function of XCL1 have been implicated in a number of diseases, including autoimmune diseases, inflammatory diseases, and cancers. For example, high levels of XCL1 have been found in the blood of patients with rheumatoid arthritis and multiple sclerosis, suggesting that it may play a role in the pathogenesis of these diseases.

In cancer, XCL1 may have both pro-tumorigenic and anti-tumorigenic effects. On one hand, it can promote tumor growth and metastasis by attracting immune-suppressive cells to the tumor microenvironment. On the other hand, it can also attract immune-stimulatory cells that can kill tumor cells.

See also

• Chemokine
• Cytokine
• T cell
• Natural killer cell
• Monocyte
• Dendritic cell
• XCR1
• Autoimmune disease
• Inflammatory disease
• Cancer

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