|PDB rendering based on 1ga3.|
|RNA expression pattern|
In addition to effects on immune cells that are similar to those of the closely related cytokine IL-4, IL-13 is more importantly implicated as a central mediator of the physiologic changes induced by allergic inflammation in many tissues. IL-13 induces its effects through a multi-subunit receptor that includes the alpha chain of the IL-4 receptor (IL-4Rα), which is also a component of the IL-4 receptor, 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).
The functions of IL-13 overlap considerably with those of IL-4, especially with regard to changes induced on hematopoietic cells, but these effects are probably less important given the more potent role of IL-4. Thus, although IL-13 can induce immunoglobulin E (IgE) secretion from activated human B cells, 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.
Although IL-13 is associated primarily with the induction of airway disease, it also has anti-inflammatory properties. Airway matrix metalloproteinases (MMPs), which are protein-degrading 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 specifically induces physiological changes in parasitized organs that are required to expel the offending organisms or their products. For example, expulsion from the gut of a variety of mouse helminths requires IL-13 secreted by Th2 cells. IL-13 induces several changes in the gut that create an environment hostile to the parasite, including enhanced contractions and glycoprotein hyper-secretion from gut epithelial cells, that ultimately lead to detachment of the organism from the gut wall and their removal.
The eggs of the parasite Schistosoma mansoni may lodge in a variety of organs including the gut wall, liver, lung and even central nervous system, inducing the formation of granulomas under the control of IL-13. Here, however, the eventual result is organ damage and often profound or even fatal disease, not resolution of the infection. An emerging concept is that IL-13 may antagonize Th1 responses that are required to resolve intracellular infections. In this immune dysregulated context, marked by the recruitment of aberrantly large numbers of Th2 cells, IL-13 inhibits the ability of host immune cells to destroy intracellular pathogens.
IL-13 induces many features of allergic lung disease, including airway hyperresponsiveness, goblet cell metaplasia and mucus hypersecretion, which all contribute to airway obstruction . IL-4 contributes to these physiologic changes, but is less important than IL-13. IL-13 also induces secretion of chemokines that are required for recruitment of allergic effector cells to the lung. Studies of STAT6 transgenic mice suggest the interesting possibility that IL-13 signaling occurring only through the airway epithelium is required for most of these effects. While no studies have yet directly implicated IL-13 in the control of human diseases, many polymorphisms in the IL-13 gene have been shown to confer an enhanced risk of atopic respiratory diseases such as asthma.
IL-13R, the IL-13 receptor
- Wynn TA. IL-13 effector functions. Annu Rev Immunol. 2003;21:425-56.
- Wills-Karp M, Luyimbazi J, Xu X, Schofield B, Neben TY, Karp CL & Donaldson DD. Interleukin-13: central mediator of allergic asthma. Science 282, 2258-2261.
- Marone G, Florio G, Petraroli A, de Paulis A (2001). "Dysregulation of the IgE/Fc epsilon RI network in HIV-1 infection.". J. Allergy Clin. Immunol. 107 (1): 22-30. PMID 11149986.
- Marone G, Florio G, Triggiani M, et al. (2001). "Mechanisms of IgE elevation in HIV-1 infection.". Crit. Rev. Immunol. 20 (6): 477-96. PMID 11396683.
- Skinnider BF, Kapp U, Mak TW (2003). "The role of interleukin 13 in classical Hodgkin lymphoma.". Leuk. Lymphoma 43 (6): 1203-10. PMID 12152987.
- Izuhara K, Arima K, Yasunaga S (2003). "IL-4 and IL-13: their pathological roles in allergic diseases and their potential in developing new therapies.". Current drug targets. Inflammation and allergy 1 (3): 263-9. PMID 14561191.
- Dessein A, Kouriba B, Eboumbou C, et al. (2005). "Interleukin-13 in the skin and interferon-gamma in the liver are key players in immune protection in human schistosomiasis.". Immunol. Rev. 201: 180-90. doi:10.1111/j.0105-2896.2004.00195.x. PMID 15361241.
- Copeland KF (2006). "Modulation of HIV-1 transcription by cytokines and chemokines.". Mini reviews in medicinal chemistry 5 (12): 1093-101. PMID 16375755.
|IL-1 superfamily||IL-1 (IL-1Ra) - IL-18 - IL-33|
|IL-6 like/gp130 utilizing||IL-6 - IL-11 - IL-27 - IL-30 - IL-31|
|IL-10 family||IL-10 - IL-19 - IL-20 - IL-22 - IL-24 - IL-26|
|Interferon type III||IL-28 - IL-29|
|Common γ-chain family||IL-2/IL-15 - IL-3 - IL-4 - IL-7 - IL-9 - IL-13 - IL-21|
|IL-12 family||IL-12 - IL-23 - IL-27 - IL-35|
|Other||IL-5 - IL-8 - IL-14 - IL-16 - IL-17/IL-25 (A) - IL-32|