Recombinant Human IL-18 Protein

IL-18 is a proinflammatory cytokine that plays an important role in NK cell activation and Th1 cell response. It is expressed as a 24 kDa precursor by endothelial and epithelial cells, keratinocytes, γδ T cells, and phagocytes. IL-18 is related to the IL-1 family in terms of both structure and function. In terms of structure, IL-18 and IL-1beta share significant primary amino acid sequences and are similarly folded as all-beta pleated sheet molecules. Also similar to IL-1beta, IL-18 is synthesized as a biologically inactive precursor molecule lacking a signal peptide. In the presence of IL-1 beta or IL-23, IL-18 induces the antigen-independent production of IL-17 by gamma δ T cells and CD4⁺T cells (11). IL-18 also promotes myeloid dendritic cell maturation and triggers neutrophil respiratory burst (12, 13). In cancer, IL-18 exhibits diverse activities including enhancing anti-tumor immunity, inhibiting or promoting angiogenesis, and promoting tumor cell metastasis.