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Induction, binding specificity and function of human ICOS

K C Beier1, A Hutloff, A M Dittrich

  • 1Molecular Immunology, Robert Koch-Institute, Berlin, Germany.

European Journal of Immunology
|February 13, 2001
PubMed

Insights

Inducible co-stimulator (ICOS) is a T cell molecule crucial for immune responses. ICOS enhances cytokine production and prevents T cell death, playing a key role in immune regulation.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Biology

Background:

  • The inducible co-stimulator (ICOS) is a T cell-specific surface molecule related to CD28 and CTLA-4.
  • ICOS plays a role in T cell activation and immune responses.

Purpose of the Study:

  • To characterize the human inducible co-stimulator (ICOS) molecule.
  • To investigate the induction, function, and expression of ICOS in T cells.

Main Methods:

  • Analysis of human ICOS protein structure and glycosylation.
  • Investigation of ICOS induction by phorbol 12-myristate 13-acetate, ionomycin, and Cyclosporin A.
  • Examination of ICOS expression during T cell activation and in various lymphoid tissues.

Main Results:

  • Human ICOS is a 55-60 kDa homodimer with distinct subunits.
  • ICOS is upregulated early in T cell activation, independent of the CD40 ligand/CD40 pathway but dependent on CD28/B7.
  • ICOS co-stimulates various cytokines (IL-4, IL-5, IL-6, IFN-γ, TNF-α, GM-CSF, IL-10) and prevents T cell apoptosis.

Conclusions:

  • ICOS is a critical co-stimulatory molecule involved in T cell activation, cytokine production, and survival.
  • ICOS expression is regulated by T cell activation signals and found in specific immune microenvironments.
  • The findings highlight ICOS as a potential therapeutic target in immune modulation.

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