Cytokines

Key Biological Properties: Interleukins are biologically active glycoproteins derived primarily from activated lymphocytes and macrophages . They induce T-lymphocyte activation and proliferation, augment neutrophil, macrophage, and T-lymphocyte cytotoxicity, and promote B lymphocyte and multilineage bone marrow stem-cell precursor growth and differentiation .

Expression Patterns and Tissue Distribution: Interleukins are produced by various cell types, including immune cells like macrophages and lymphocytes . They are expressed in different tissues, such as the bone marrow, thymus, and other epithelial cells .

Primary Biological Functions: Interleukins modulate the growth, differentiation, and activation of immune cells during inflammatory and immune responses . They play a role in both innate and adaptive immune responses .

Role in Immune Responses and Pathogen Recognition: Interleukins are involved in the regulation of immune responses, inflammatory reactions, and hematopoiesis . They help coordinate the body’s response to infections, inflammation, and other immune challenges .

Mechanisms with Other Molecules and Cells: Interleukins interact with specific cell surface receptors to stimulate target cells . For example, IL-6 controls leucocyte recruitment, determines the activity and maintenance of the inflammatory infiltrate, and drives various innate and adaptive immune responses .

Binding Partners and Downstream Signaling Cascades: Interleukins bind to their respective receptors, triggering downstream signaling pathways such as the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathways . These signaling cascades lead to various cellular responses, including proliferation, differentiation, and cytokine production .

Regulatory Mechanisms Controlling Expression and Activity: The expression and activity of interleukins are regulated by complex molecular mechanisms. For example, IL-10 production is regulated by metabolic pathways and molecular signals downstream of the IL-10 receptor .

Transcriptional Regulation and Post-Translational Modifications: Interleukins undergo transcriptional regulation and post-translational modifications to ensure proper function. These modifications can include phosphorylation, glycosylation, and cleavage .

Biomedical Research: Interleukins are extensively studied in biomedical research for their roles in immune regulation and disease pathogenesis .

Diagnostic Tools: Interleukins serve as biomarkers for various diseases, aiding in diagnosis and monitoring of disease progression .

Therapeutic Strategies: Interleukins are used in therapeutic strategies, such as cancer immunotherapy and treatment of autoimmune diseases . For example, engineered cytokines from the IL-2 family have shown significant effects in tumor immunotherapy .

Role Throughout the Life Cycle: Interleukins play essential roles throughout the life cycle, from development to aging and disease. They regulate hematopoiesis, immune responses, and inflammation . For instance, IL-5 regulates eosinophil proliferation and differentiation, while IL-1 is involved in inflammatory responses .