Long-term engagement of CD6 and ALCAM is essential for T-cell proliferation induced by dendritic cells

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Artificial Antigen Presenting Cell (aAPC) Mediated Activation and Expansion of Natural Killer T Cells
13:18

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Published on: December 29, 2012

Aukje W Zimmerman1, Ben Joosten, Ruurd Torensma

  • 1Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, The Netherlands.

Blood
|December 15, 2005
PubMed

Insights

CD6 and ALCAM are crucial for T-cell activation. This receptor-ligand pair stabilizes T-cell interactions with antigen-presenting cells and promotes T-cell proliferation, essential for adaptive immunity.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Interactions

Background:

  • Adaptive immune responses initiate with T cell and antigen-presenting cell (APC) interactions.
  • Stable cell-cell contact is critical for effective immune signaling and T cell activation.

Purpose of the Study:

  • To investigate the role of CD6 and its ligand, activated leukocyte cell adhesion molecule (ALCAM), in T cell-APC interactions.
  • To determine the contribution of CD6-ALCAM binding to T cell proliferation and immune response induction.

Main Methods:

  • Utilized blocking antibodies and recombinant proteins to inhibit CD6-ALCAM interactions.
  • Analyzed dendritic cell (DC)-T cell conjugate formation and T cell proliferation assays.
  • Investigated transcriptional activity following CD6 and CD3 co-crosslinking.

Main Results:

  • CD6 and ALCAM were recruited to the DC-T cell contact zone.
  • ALCAM-blocking antibodies impaired DC-T cell conjugate formation, highlighting CD6-ALCAM's role in stable contact.
  • CD6-blocking antibodies and ALCAM-Fc proteins significantly inhibited T cell proliferation.
  • Simultaneous crosslinking of CD6 and CD3 enhanced T cell proliferation and transcriptional activity.

Conclusions:

  • CD6-ALCAM interaction is essential for both initial DC-T cell binding and sustained T cell proliferation.
  • CD6 functions as a significant costimulatory molecule, comparable to CD28, in T cell activation.
  • The stable nature of ALCAM-CD6 binding contributes to its long-lasting effects on T cell proliferation.

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