The recombinant human IL4, with a 6xHis tag at the N-terminus, is expressed in the yeast system by co-cloning the IL4 gene fragment (25-153aa) into a suitable expression vector. The recombinant vectors are introduced into yeast cells for protein expression by IPTG induction. Once the recombinant IL4 is produced, the cells are lysed to release the protein, which is purified using Ni-NTA affinity chromatography. This method takes advantage of the affinity between the 6xHis tag and nickel ions. After elution, the purified IL4 protein is evaluated for purity using SDS-PAGE, which consistently demonstrates a purity greater than 90%.
Human IL4 is a pivotal cytokine predominantly produced by Th2 cells, playing a crucial role in the regulation of immune responses and inflammation. It is primarily known for its involvement in the differentiation of naive T cells into Th2 cells, which are essential for orchestrating the immune response against allergens and parasites [1][2]. IL4 promotes immunoglobulin class switching, particularly the transition from IgM to IgE, which is a hallmark of allergic reactions [1][2]. This cytokine is also implicated in various pathological conditions, including asthma, where it contributes to airway hyperresponsiveness and inflammation [2][3].
The binding of IL4 to its receptor IL4R activates several intracellular signaling pathways, notably the JAK/STAT pathway, leading to the transcription of genes associated with Th2 differentiation and function [4][5]. This signaling cascade is crucial for the production of other cytokines such as IL5 and IL13, further amplifying the Th2 response [2][3].
In addition to its role in allergic responses, IL4 is involved in tissue repair and remodeling processes. It has been shown to enhance the migration and differentiation of myogenic precursor cells, indicating its potential role in muscle regeneration [6]. Furthermore, IL4 influences the production of extracellular matrix components, such as fibronectin, in fibroblasts, which is relevant in conditions like asthma and fibrosis [7]. The cytokine's ability to modulate immune cell activity also extends to its effects on macrophages, where it promotes an alternatively activated phenotype associated with tissue repair and anti-inflammatory responses [8].
Moreover, IL4 has been linked to various malignancies, where it can influence tumor growth and the immune microenvironment [9][10]. Its expression is often upregulated in cancers, and it can facilitate tumor progression by modulating the immune response within the tumor microenvironment [9][10].
References:
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[2] W. Busse, M. Kraft, K. Rabe, Y. Deniz, P. Rowe, M. Ruddy, et al. Understanding the key issues in the treatment of uncontrolled persistent asthma with type 2 inflammation, European Respiratory Journal, vol. 58, no. 2, p. 2003393, 2021. https://doi.org/10.1183/13993003.03393-2020
[3] H. Tang, Y. Song, J. Chen, J. Chen, & P. Wang, Upregulation of phosphodiesterase-4 in the lung of allergic rats, American Journal of Respiratory and Critical Care Medicine, vol. 171, no. 8, p. 823-828, 2005. https://doi.org/10.1164/rccm.200406-771oc
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[5] A. Suzuki, P. Leland, B. Joshi, & R. Puri, Targeting of il-4 and il-13 receptors for cancer therapy, Cytokine, vol. 75, no. 1, p. 79-88, 2015. https://doi.org/10.1016/j.cyto.2015.05.026
[6] J. Lafrenière, P. Mills, M. Bouchentouf, & J. Tremblay, Interleukin-4 improves the migration of human myogenic precursor cells in vitro and in vivo, Experimental Cell Research, vol. 312, no. 7, p. 1127-1141, 2006. https://doi.org/10.1016/j.yexcr.2006.01.002
[7] T. Machino, S. Hashimoto, Y. Gon, K. Kujime, S. Maruoka, & T. Horie, Interleukin-4 and interleukin-13 induce fibronectin production by human lung fibroblasts, Allergology International, vol. 50, no. 3, p. 197-202, 2001. https://doi.org/10.1046/j.1440-1592.2001.00220.x
[8] R. Snodgrass, E. Zezina, D. Namgaladze, S. Gupta, C. Angioni, G. Geißlinger, et al. A novel function for 15-lipoxygenases in cholesterol homeostasis and ccl17 production in human macrophages, Frontiers in Immunology, vol. 9, 2018. https://doi.org/10.3389/fimmu.2018.01906
[9] M. Kang, J. Lee, S. Ha, C. Lee, K. Kim, K. Janget al., Interleukin4rα (il4rα) and il13rα1 are associated with the progress of renal cell carcinoma through janus kinase 2 (jak2)/forkhead box o3 (foxo3) pathways, Cancers, vol. 11, no. 9, p. 1394, 2019. https://doi.org/10.3390/cancers11091394
[10] K. Bankaitis and B. Fingleton, Targeting il4/il4r for the treatment of epithelial cancer metastasis, Clinical & Experimental Metastasis, vol. 32, no. 8, p. 847-856, 2015. https://doi.org/10.1007/s10585-015-9747-9
