Mediators of the Acute Phase Response: The Role of Cytokines

Cytokines are polypeptides or glycopeptides involved in intercellular communication, functioning as key mediators alongside hormones and neurotransmitters. Acting through specific receptors, cytokines regulate gene activation, influencing cellular function and phenotype. Their activity is modulated by inhibitors that control biological effects and cellular responses. Classified based on function, cytokines include growth factors, proinflammatory cytokines, and anti-inflammatory cytokines. Proinflammatory cytokines such as TNF-α, IL-1β, and IL-6 play a crucial role in inflammation, mediating immune responses, fever, and metabolic changes. They induce leukocyte activation, protein catabolism, and alterations in endocrine function, contributing to immune regulation and systemic effects. Additionally, cytokines influence metabolism by modulating nutrient absorption, energy balance, and acute-phase protein synthesis. This review highlights the fundamental properties, classification, and biological effects of cytokines, emphasizing their central role in immune function, metabolism, and inflammation. Understanding cytokine interactions is essential for developing therapeutic strategies targeting immune and inflammatory disorders.