Table 4.

Characteristics of cytokines^a

Name	Source	Biological role
Interleukin – 18 (IL-18)	Produced by macrophages and monocytes	Pro-inflammatory cytokine interacts with IL-12 to induce cell-mediated immune response with microbial infection and LPS, inducing severe inflammatory reactions. Stimulates NK and T cell release of IFN-γ, which activates macrophages.
Interleukin – 8 (IL-8)	Produced macrophages and some epithelial and endothelial cells	Role in innate immune response. Major role in chemotaxis of Neutrophils. Also mediates inflammatory response and angiogenesis.
Interleukin – 1-beta (IL-1β)	Produced by activated macrophages	Mediates inflammatory responses, cell proliferation, apoptosis. Induces Cox-2 in CNS, causing inflammatory pain.
Interleukin – 10 (IL-10)	Produced by monocytes. Pleiotropic cytokine	An anti-inflammatory cytokine, it inhibits macrophage and dendritic cell function, suppresses TNF-α. Acquires pro-inflammatory activity during immune response with IFN-α stimulation.
Interferon gamma-soluble cytokine (IFN-γ)	Produced by innate NK cells, acquired antigen-specific cytotoxic CD4+ and effector CD8+ T cells.	Activates macrophages and critical for innate and adaptive immune responses to intracellular pathogens, tumor control, and inhibition of viral replication.
Tumor Necrosis factor-alpha (TNF-α)	Secreted by macrophages, monocytes, neutrophils, T cells, NK cells after stimulation with LPS.	CD4+ cells secrete TNF-α. Also made by astrocytes, microglial cells, smooth muscle cells, and fibroblasts. Mediates systemic inflammation, inhibits viral replication, and inhibits tumorigenesis.
Interleukin – 6 (IL-6)	Secreted by T cells and macrophages;	Triggers inflammation, acute phase response, fever. Anti-inflammatory effects include inhibiting TNF-α and IL-1, and activating IL-1ra and IL-10