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ICOS

Function

Stimulatory receptor expressed in activated or antigen-experienced T-cells that plays an important role in the immune response (PubMed:9930702). Upon binding to its ligand ICOSL expressed on antigen presenting cells (APCs), delivers costimulatory signals that enhances all basic T-cell responses to a foreign antigen, namely proliferation, secretion of lymphokines including IL10, up-regulation of molecules that mediate cell-cell interaction, and effective help for antibody secretion by B-cells (PubMed:33033255). Acts also as a costimulatory receptor critical for the differentiation of T follicular regulatory cells upon immune challenges such as viral infection (PubMed:27135603). Mechanistically, potentiates TCR-induced calcium flux by augmenting PLCG1 activation and actin remodeling (By similarity). In addition, activates PI3K signaling pathways independently of calcium flux (PubMed:30523347). Essential both for efficient interaction between T and B-cells and for normal antibody responses to T-cell dependent antigens. Prevents the apoptosis of pre-activated T-cells. Plays a critical role in CD40-mediated class switching of immunoglobin isotypes (By similarity).

Involvement in disease

Immunodeficiency, common variable, 1

CVID1

A primary immunodeficiency characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen. The defect results from a failure of B-cell differentiation and impaired secretion of immunoglobulins; the numbers of circulating B-cells is usually in the normal range, but can be low.

None

The disease is caused by variants affecting the gene represented in this entry.

Post-translational modifications

N-glycosylated.

Tissue specificity

Activated T-cells. Highly expressed on tonsillar T-cells, which are closely associated with B-cells in the apical light zone of germinal centers, the site of terminal B-cell maturation. Expressed at lower levels in thymus, lung, lymph node and peripheral blood leukocytes. Expressed in the medulla of fetal and newborn thymus.

Cellular localization

  • Isoform 1
  • Cell membrane
  • Single-pass type I membrane protein
  • Isoform 2
  • Secreted

Alternative names

  • AILIM
  • AILIM
  • ICOS
  • Inducible T-cell costimulator
  • Activation-inducible lymphocyte immunomediatory molecule

Target type

Proteins

Primary research area

Immuno-oncology

Other research areas

  • Immunology & Infectious Disease

Molecular weight

22625Da

We found 21 products in 2 categories

Primary Antibodies

Proteins & Peptides

Target

Species of origin

Nature