The interleukin-1 (IL-1) family of cytokines and receptors is unique in immunology due to its shared functions with the Toll-like receptor (TLR) families. The IL-1 family is primarily associated with innate immunity, which is crucial for survival in over 95% of living organisms. Innate immunity, characterized by inflammation, can be beneficial as a host defense mechanism but can also be detrimental if uncontrolled. The IL-1 family members, including IL-1α, IL-1β, and IL-33, share a common cytoplasmic Toll-IL-1-Receptor (TIR) domain, which is highly homologous to the TIR domains of TLRs. IL-1 family cytokines trigger innate inflammation via IL-1 receptors, while TLRs respond to bacteria, microbial products, viruses, nucleic acids, and damage-associated molecular patterns (DAMPs). IL-1α and IL-33 also function as DAMPs. While the inflammatory properties of the IL-1 family dominate in innate immunity, some members can play a role in acquired immunity. The IL-1 family consists of 11 cytokines and 10 receptors. The cytokines lack a signal peptide and are found in the cytoplasm as precursors, containing a conserved A-X-D motif. The receptors, such as IL-1R1, bind to various cytokines and form trimeric signaling complexes with coreceptors like IL-1R3. The signaling cascade involves MyD88 and kinases, leading to the activation of NFκB. Some receptors, like IL-1R8 and IL-1R9, have anti-inflammatory functions. IL-1α is a dual-function cytokine, acting both in the nucleus and on cell membrane receptors. It is constitutively present in epithelial and mesenchymal cells and functions as an alarmin. IL-1β is primarily induced under disease conditions and plays a crucial role in inflammation and autoinflammatory diseases. IL-1Ra, an antagonist of IL-1, is used in the treatment of rheumatoid arthritis and other inflammatory conditions. IL-33, another member of the IL-1 family, is released upon cell damage and acts as a DAMP. It has both pro-inflammatory and anti-inflammatory properties, depending on the context. IL-18, another cytokine, is processed by caspase-1 and plays a role in Th1 responses and immune regulation. IL-18BP, a soluble receptor, binds to IL-18 and reduces its activity, contributing to immune regulation. Overall, the IL-1 family of cytokines and receptors plays a central role in both innate and acquired immunity, with diverse functions in inflammation, infection, and immune responses.The interleukin-1 (IL-1) family of cytokines and receptors is unique in immunology due to its shared functions with the Toll-like receptor (TLR) families. The IL-1 family is primarily associated with innate immunity, which is crucial for survival in over 95% of living organisms. Innate immunity, characterized by inflammation, can be beneficial as a host defense mechanism but can also be detrimental if uncontrolled. The IL-1 family members, including IL-1α, IL-1β, and IL-33, share a common cytoplasmic Toll-IL-1-Receptor (TIR) domain, which is highly homologous to the TIR domains of TLRs. IL-1 family cytokines trigger innate inflammation via IL-1 receptors, while TLRs respond to bacteria, microbial products, viruses, nucleic acids, and damage-associated molecular patterns (DAMPs). IL-1α and IL-33 also function as DAMPs. While the inflammatory properties of the IL-1 family dominate in innate immunity, some members can play a role in acquired immunity. The IL-1 family consists of 11 cytokines and 10 receptors. The cytokines lack a signal peptide and are found in the cytoplasm as precursors, containing a conserved A-X-D motif. The receptors, such as IL-1R1, bind to various cytokines and form trimeric signaling complexes with coreceptors like IL-1R3. The signaling cascade involves MyD88 and kinases, leading to the activation of NFκB. Some receptors, like IL-1R8 and IL-1R9, have anti-inflammatory functions. IL-1α is a dual-function cytokine, acting both in the nucleus and on cell membrane receptors. It is constitutively present in epithelial and mesenchymal cells and functions as an alarmin. IL-1β is primarily induced under disease conditions and plays a crucial role in inflammation and autoinflammatory diseases. IL-1Ra, an antagonist of IL-1, is used in the treatment of rheumatoid arthritis and other inflammatory conditions. IL-33, another member of the IL-1 family, is released upon cell damage and acts as a DAMP. It has both pro-inflammatory and anti-inflammatory properties, depending on the context. IL-18, another cytokine, is processed by caspase-1 and plays a role in Th1 responses and immune regulation. IL-18BP, a soluble receptor, binds to IL-18 and reduces its activity, contributing to immune regulation. Overall, the IL-1 family of cytokines and receptors plays a central role in both innate and acquired immunity, with diverse functions in inflammation, infection, and immune responses.