ICOSLG

ICOSLG
Identifiers
Aliases	ICOSLG, B7-H2, B7H2, B7RP-1, B7RP1, CD275, GL50, ICOS-L, ICOSL, LICOS, inducible T-cell co-stimulator ligand, inducible T-cell costimulator ligand, inducible T cell costimulator ligand, B7h
External IDs	OMIM: 605717; MGI: 1354701; HomoloGene: 49412; GeneCards: ICOSLG; OMA:ICOSLG - orthologs
Gene location (Human)
Chr.	Chromosome 21 (human)
End	44,240,966 bp
Gene location (Mouse)
Chr.	Chromosome 10 (mouse)
End	77,919,747 bp
RNA expression pattern
	Top expressed in
	cartilage tissue; ; apex of heart; ; C1 segment; ; corpus callosum; ; putamen; ; bone marrow cells; ; substantia nigra; ; skin of limb; ; skin of leg; ; skin of abdomen;
	Top expressed in
	granulocyte; ; zygote; ; mesenteric lymph nodes; ; spleen; ; secondary oocyte; ; cumulus cell; ; primary oocyte; ; blood; ; subcutaneous adipose tissue; ; submandibular gland;
	More reference expression data
	More reference expression data
Gene ontology
Molecular function	signaling receptor binding; protein binding; identical protein binding;
Cellular component	integral component of membrane; extracellular exosome; membrane; plasma membrane; external side of plasma membrane; cytoplasmic ribonucleoprotein granule;
Biological process	B cell activation; defense response; T cell costimulation; adaptive immune response; hyperosmotic response; T cell activation; signal transduction; positive regulation of activated T cell proliferation; immune system process; regulation of immune response; T cell receptor signaling pathway;
	Sources:Amigo / QuickGO
Orthologs
	23308
	50723
	ENSG00000160223
	ENSMUSG00000000732
	O75144
	Q9JHJ8
NM_001283050; NM_001283051; NM_001283052; NM_015259; NM_001365759;
	NM_001395918
	NM_015790
	NP_001269979; NP_001269980; NP_001269981; NP_056074; NP_001352688
	NP_056605
	Wikidata
View/Edit Human	View/Edit Mouse

ICOS ligand is a protein that in humans is encoded by the ICOSLG gene located at chromosome 21. ICOSLG has also been designated as CD275 (cluster of differentiation 275).

ICOSLG is glycosylated transmembrane structure, which is classified as a member of the B7 family due to the significant homology with B7 family members. The B7/CD28 superfamily provides both positive and negative co-signals to immunocytes in immune responses.

The interaction of ICOSLG with ICOS, the specific receptor for ICOSLG, is critically involved in the activation, proliferation, differentiation and cytokine production of T cells as well as in the antibody secretion from B cells during secondary immune responses.

ICOSLG, which is extensively expressed in both non-lymphatic and lymphatic tissues, is an important molecule in upregulating and promoting T cell immune responses. Expression of ICOSLG in naive B cells and monocytes in PBMCs is at a low level. After stimulation by IFN-γ, TNF-α, or LPS, it can be quickly up-regulated. The induced expression of ICOS on activated T cells mainly regulates the secretion of Th2 cytokines and thus shifts the immune response to the Th2 type. It has been reported that the ICOS/ICOSLG pathway is involved in immunopathogenesis such as infection, hypersensitivity, autoimmune diseases, transplantation immunity and tumor immunity.

ICOSLG is also a major costimulator in endothelial cell-mediated T cell activation. It has an important physiological role of ICOSLG in the reactivation of effector/memory T cells on the endothelium controlling the entry of immune cells into inflamed tissue.