Inducible T cell costimulator ligand (ICOSLG)

Inducible T cell costimulator ligand (ICOSLG) is a glycosylated transmembrane protein, classified within the B7 family of costimulatory molecules that provide positive and negative co-signals during immune responses[1][2][5]. ICOSLG binds the ICOS receptor on T cells to deliver crucial costimulatory signals for T cell activation, proliferation, differentiation, and cytokine production; it is also required for optimal antibody secretion from B cells in secondary immune responses[1][5]. ICOSLG is broadly expressed in both lymphoid and non-lymphoid tissues, with higher expression following immune activation. Dysregulation of the ICOSLG pathway is linked to inflammatory and immune diseases such as cancer, autoimmunity, hypersensitivity, infection, and immunodeficiency (e.g., ICOSLG deficiency leads to defective antibody/memory B cell generation and neutrophil migration)[1][3]. ICOSLG is a key axis in immunotherapy, with both antagonists and agonists under investigation for cancer and autoimmune disease, as its modulation can shift immune responses toward tumor rejection or tolerance depending on cellular context[1].

Other names

ICOS ligandB7H2B7RP1ICOSLKIAA0653CD275B7-H2B7RP-1GL50B7hLICOSIMD119B7-like protein Gl50B7 homolog 2B7 homologue 2B7-related protein 1transmembrane protein B7-H2 ICOS ligand

Blockade or agonism of ICOSLG to modulate T cell co-stimulation, shifting immune response, either activating or inhibiting depending on immunotherapeutic intent Inhibition of ICOS/ICOSLG interaction to dampen autoimmune response