Interleukin
A large family of cytokines (IL-1 through IL-40+) that mediate communication between immune cells. Different interleukins promote or suppress inflammation, activate specific immune cell types, and regulate immune responses. Interleukin levels are often measured as biomarkers of inflammatory activity.
Technical Context
Key interleukins in peptide drug contexts: IL-2 (T cell growth factor — cyclosporine blocks its production; IL-2 production is the primary downstream consequence of calcineurin-NFAT signalling that cyclosporine inhibits), IL-6 (pro-inflammatory — elevated in CRS, autoimmune diseases; produced by activated macrophages and T cells), IL-10 (anti-inflammatory — produced by Treg cells; glatiramer acetate treatment increases IL-10 production), IL-1β (pro-inflammatory — involved in inflammasome-mediated inflammation), IL-4 and IL-13 (Th2 cytokines — promote B cell class switching to IgE, allergic inflammation), IL-17 (Th17 cytokine — involved in autoimmune inflammation), and IL-21 (Tfh cytokine — critical for germinal centre B cell responses and antibody production, relevant to ADA formation against peptide drugs). Interleukin measurement (by ELISA, multiplex immunoassay, or flow cytometry) is used in clinical trials to characterise immune responses to peptide therapeutics.