Table 1.

Details of six cytokine families and examples of family members.

Cytokine Family	Examples	Characteristics
Interleukin 1 family	IL-1α, IL-β, IL-RA	Induce responses against infection that are primarily pro-inflammatory IL-RA antagonizes effects of IL-1α and IL-β
Hematopoietin (Class I cytokine) family	IL-2, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12p40, IL-12p70, IL-13, IL-15, IL-23, GM-CSF, G-CSF	Largest family of cytokines, all members sharing a 4-helix bundle structure Sequence and functional diversity Diverse effects include proliferation, differentiation, and antibody secretion
Interferon (Class II cytokine) family	IFN-γ, IL-10	Mediate early antiviral responses Activate macrophages, interact with cells of the adaptive immune system, and support the generation of Th1 cells
Tumor necrosis factor family	TNF-α, TNF-β1	Expressed in either soluble or membrane-bound form Cause apoptosis
Interleukin 17 family	IL-17	Primarily pro-inflammatory
Chemokine family	IL-8, Eotaxin, IP-10 (CXCL10), MCP-1(CCL2), MIP-1α (CCL3), MIP-1β (CCL4), RANTES (CCL5)	Secondary pro-inflammatory mediators Stimulate recruitment of well-defined leukocyte subsets Promote chemoattraction, movement of immune system cells into, within, and out of lymphoid organs

CCL, chemokine (C-C motif) ligand; CXCL, chemokine (C-X-C) ligand; G-CSF, granulocyte colony-stimulating factor; GM-CSF, granulocyte macrophage colony-stimulating factor; IFN-γ, interferon-γ; IL, interleukin; IL.1RA, IL-1 receptor antagonist; IP-10, IFNγ-inducible protein 10; MCP-1, monocyte chemotactic protein-1; MIP-1α, macrophage inflammatory protein-1α; MIP-1β, macrophage inflammatory protein-1β; RANTES, regulated on activation, normal T cell expressed and secreted; Th, T helper; TNF-α, tumor necrosis factor-α.