Functions
IL-13 has effects on immune cells that are similar to those of the closely related cytokine IL-4. However, IL-13 is suspected to be a more central mediator of the physiologic changes induced by allergic inflammation in many tissues.
Although IL-13 is associated primarily with the induction of airway disease, it also has anti-inflammatory properties. IL-13 induces a class of protein-degrading enzymes, known as matrix metalloproteinases (MMPs), in the airways. These enzymes are required to induce egression of effete parenchymal inflammatory cells into the airway lumen where they are then cleared. Among other factors, IL-13 induces these MMPs as part of a mechanism that protects against excessive allergic inflammation that predisposes to asphyxiation.
IL-13 is known to induce changes in hematopoietic cells, but these effects are probably less important that that of IL-4. Furthermore, IL-13 can induce immunoglobulin E (IgE) secretion from activated human B cells. Interestingly, deletion of IL-13 from mice does not markedly affect either Th2 cell development or antigen-specific IgE responses induced by potent allergens. In comparison, deletion of IL-4 abrogates these responses. Thus, rather than a lymphoid cytokine, IL-13 acts more prominently as a molecular bridge linking allergic inflammatory cells to the non-immune cells in contact with them, thereby altering physiological function.
IL-13 induces its effects through a multi-subunit receptor that includes the alpha chain of the IL-4 receptor (IL-4Rα) and at least one of two known IL-13-specific binding chains. Most of the biological effects of IL-13, like those of IL-4, are linked to a single transcription factor, signal transducer and activator of transcription 6 (STAT6). This can be resulted from an allergic reaction brought about when facing an Ala gene.
Read more about this topic: Interleukin 13
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