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CD80 cytoplasmic domain controls localization of CD28, CTLA-4, and protein kinase Ctheta in the immunological synapse

Su-Yi Tseng1, Mengling Liu, Michael L Dustin

  • 1New York University School of Medicine, Skirball Institute, New York, NY 10016, USA.

Journal of Immunology (Baltimore, Md. : 1950)
|December 13, 2005
PubMed

Insights

The cytoplasmic tail of costimulatory molecule CD80 is crucial for T cell activation. Its absence impairs T cell proliferation and IL-2 production by altering CD80 localization within the immunological synapse.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • The interaction between costimulatory ligand CD80 and its receptors CD28 or CTLA-4 on T cells is vital for regulating T cell responses.
  • Understanding the structural and functional significance of CD80's cytoplasmic domain is essential for deciphering T cell activation mechanisms.

Purpose of the Study:

  • To investigate the role of the cytoplasmic domain of CD80 in murine T cell costimulation.
  • To analyze the organization and localization of CD80 within the immunological synapse (IS).

Main Methods:

  • Utilized T cell costimulation assays to assess proliferative responses and IL-2 production.
  • Employed immunofluorescence microscopy to study the localization of full-length and tailless CD80 in the IS.
  • Investigated the colocalization of CD80, CD28, and protein kinase Ctheta (PKCθ).

Main Results:

  • Removal of the CD80 cytoplasmic tail significantly reduced its costimulatory capacity, impairing T cell proliferation and early IL-2 production.
  • Tailless CD80 showed decreased accumulation in the IS of naive T cells compared to full-length CD80.
  • Full-length CD80 segregated from the T cell receptor (TCR) at the IS, while tailless CD80 colocalized with the TCR.
  • CD80, CD28, and PKCθ colocalized irrespective of the presence or absence of the CD80 cytoplasmic tail.

Conclusions:

  • The cytoplasmic tail of CD80 is critical for its proper spatial organization within the IS.
  • CD80's localization at the IS influences the arrangement of its receptors and associated signaling molecules like PKCθ.
  • Proper localization mediated by the CD80 cytoplasmic tail is necessary for complete T cell activation.

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