Interleukin 6 and Tumor necrosis factor alpha (IL-6 and TNF-α)

Interleukin 6 (IL–6) is a pleiotropic cytokine produced by various cell types including monocytes, macrophages, T cells, B cells, endothelial cells and fibroblasts. It acts as both a pro-inflammatory cytokine—promoting immune responses during infection or tissue injury—and an anti-inflammatory myokine. Its biological effects are mediated through binding to the interleukin 6 receptor complex composed of the ligand-binding subunit (IL–6Rα/CD126) and the signal-transducing component gp130/CD130. This interaction activates intracellular JAK/STAT signaling cascades that regulate gene expression involved in immune cell differentiation (notably Th17/Treg balance), acute phase protein production by hepatocytes, B-cell maturation into plasma cells for antibody production and other processes[1][2][4][7]. Tumor necrosis factor alpha (TNF–alpha, also written as TNF–α) is another key pro-inflammatory cytokine produced mainly by activated macrophages but also by T-cells and other immune cells. It exerts its effects via two receptors—TNFR1/p55/CD120a and TNFR2/p75/CD120b—leading to activation of NF-kB pathway among others. It plays central roles in systemic inflammation; mediating fever induction; apoptosis; leukocyte recruitment; upregulation of adhesion molecules on endothelial cells; stimulation/induction/regulation/release/production/expression/secretion/synthesis/biosynthesis/generation/mobilization/distribution/circulation/concentration/activity/function/effectiveness/responsiveness/sensitivity/reactivity/interactivity/interplay/interconnection/interdependence/cooperation/collaboration/synergy between multiple components within innate/adaptive immunity[3][4]. Both molecules are implicated in numerous pathological conditions characterized by excessive inflammation such as autoimmune diseases (e.g., rheumatoid arthritis), cancer progression/metastasis via modulation of tumor microenvironment angiogenesis/proliferation/apoptosis pathways[5][6], severe infections including sepsis/COVID19-associated “cytokine storm,” cardiovascular disorders etc.[1][4].

Other names

IL6TNF-alphaTumor necrosis factor alphaInterleukin-6TNFα

For IL-6 targeting drugs: Blockade of the IL-6 receptor or neutralization of circulating IL-6 to inhibit downstream pro-inflammatory signaling. For TNF-alpha targeting drugs: Neutralization of soluble and membrane-bound TNF-alpha to prevent activation of its receptors and downstream inflammatory pathways.