For the production of the recombinant human IL18 protein with an N-terminal 6xHis-tag in yeast, the gene of interest, fused with the N-terminal 6xHis-tag sequence, is cloned into an expression vector and introduced into the yeast cells. The gene of interest codes for the full length of the mature human IL18 (37-193aa). After that, the positive yeast cells are cultured and induced for protein expression. The recombinant IL18 protein is isolated and purified using nickel affinity chromatography from the cell lysate. Its purity is assessed by SDS-PAGE, exceeding 90%.
IL18, also called IFN-γ-inducing factor, is a pleiotropic cytokine that plays a crucial role in regulating both innate and acquired immune responses [1]. Most normal human cells, particularly macrophages and dendritic cells, can produce IL18 [2]. IL18 is an inflammasome-induced proinflammatory cytokine that enhances the activity of T- and NK-cells and stimulates the production of IFNγ [3]. IL18 acts as a proinflammatory and immune regulatory cytokine in different types of cancer[4]. In non-small cell lung cancer, polymorphisms in the IL18 gene have been linked to susceptibility, affecting the activation of natural killer cell cytotoxicity and promoting the Th1 immune response through the alteration of interferon-γ and TNF-α expression [5]. Furthermore, IL18 is involved in inflammatory bowel diseases, with pharmacologic inhibition of IL18 reversing severe enterocolitis, indicating its potential as a therapeutic target for such conditions [6].
References:
[1] D. Zhang, X. Zhang, F. Li, Y. Zhao, X. Li, J. Wanget al., Expression profiles of the ovine il18 gene and association of its polymorphism with hematologic parameters in hu lambs, Frontiers in Veterinary Science, vol. 9, 2022. https://doi.org/10.3389/fvets.2022.925928
[2] X. Wang, W. Zhu, L. Qian, E. Chen, H. Sun, X. Liet al., The prognostic value and immune correlation of il18 expression and promoter methylation in renal cell carcinoma, Clinical Epigenetics, vol. 15, no. 1, 2023. https://doi.org/10.1186/s13148-023-01426-8
[3] A. Menachem, Unleashing natural il18 activity using an anti-il18bp blocker induces potent immune stimulation and antitumor effects, Cancer Immunology Research, vol. 12, no. 6, p. 687-703, 2024. https://doi.org/10.1158/2326-6066.cir-23-0706
[4] M. Fabbi, G. Carbotti, & S. Ferrini, Context-dependent role of il-18 in cancer biology and counter-regulation by il-18bp, Journal of Leukocyte Biology, vol. 97, no. 4, p. 665-675, 2014. https://doi.org/10.1189/jlb.5ru0714-360rr
[5] C. Dinarello, Novel targets for interleukin 18 binding protein, Annals of the Rheumatic Diseases, vol. 60, no. suppl 3, p. iii18-iii24, 2001. https://doi.org/10.1136/ard.60.90003.iii18
[6] C. Dinarello, Targeting interleukin 18 with interleukin 18 binding protein, Annals of the Rheumatic Diseases, vol. 59, no. 90001, p. 17i-20, 2000. https://doi.org/10.1136/ard.59.suppl_1.i17
