ICOS
Full name: Inducible T-cell costimulator
Aliases:1 AILIM, CD278, and CVID1
Size:2 55–60 kDa
Family:1,2 CD28 and CTLA-4 cell-surface receptor family of costimulatory molecules
Receptors:1 CD28 and CTLA-4 cell-surface receptor family
Major cellular sources:2-6 Activated and germinal center T cells and naïve T cells
Major cellular targets:5-8 Th-cell cytokines, including IFN-γ, TNF-α, IL-4, IL-5, IL-10, and IL-13
Disease states associated with:6 Systemic lupus erythematosus
Major physiologic functions:
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ICOS is expressed on activated and germinal center T cells and interacts with its only known ligand, ICOS-L.2-6
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ICOS forms homodimers and plays an important role in cell-cell signaling, immune responses, and regulation of cell proliferation.1,2
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ICOS is either absent or expressed at very low levels on naïve T cells, but it is upregulated upon stimulation, suggesting that its costimulatory role is more important for memory and effector T cells.7
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ICOS/ICOS-L costimulation plays a role in the production of certain Th-cell cytokines, including IFN-γ, TNF-α, IL-4, IL-5, IL-10, and IL-13, and promotes the migration, development, and activation of lymphocytes as well as antibodies produced by B cells.6-8
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ICOS is an essential mediator of Th2-cell function in humoral immune responses.5
References:
- 1.
NCBI. Gene. ICOS inducible T cell costimulator [Homo sapiens (human)]. www.ncbi.nlm.nih.gov/gene/29851. Accessed March 11, 2021.
- 2.
Mages HW, Hutloff A, Heuck C, et al. Eur J Immunol. 2000;30:1040-1047.
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3.
Coyle AJ, Lehar S, Lloyd C, et al. Immunity. 2000;13:95-105.
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4.
Dong C, Juedes AE, Temann UA, et al. Nature. 2001;409:97-101.
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5.
Dong C, Temann UA, Flavell RA. J Immunol. 2001;166:3659-3662.
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6.
Wikenheiser DJ, Stumhofer JS. Front Immunol. 2016;7:304.
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7.
Frauwirth KA, Thompson CB. J Clin Invest. 2002;109:295-299.
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8.
Vieira PL, Wassink L, Smith LM, et al. Eur J Immunol. 2004;34:1282-1290.