Cytokine

Cytokines are a broad category of small signalling proteins (typically 5-25 kDa) secreted by a wide range of cells, including immune cells (macrophages, lymphocytes, dendritic cells) and non-immune cells (fibroblasts, endothelial cells). They act through specific cell-surface receptors to regulate inflammation, immunity, haematopoiesis, and tissue repair. Major cytokine families include interleukins, tumour necrosis factors, interferons, chemokines, and colony-stimulating factors. Cytokines can be pro-inflammatory (IL-1, IL-6, TNF-alpha) or anti-inflammatory (IL-10, TGF-beta), and their balance determines whether an inflammatory response resolves normally or becomes chronic. Research peptides like BPC-157 and TB-500 have been shown to modulate cytokine profiles, typically shifting the balance toward resolution of inflammation.