Volume 6 Issue 2, February 2005

Volume 6 Issue 2

Positive selection of thymocytes requires calcium signaling. Lewis and colleagues (p 143; News and Views by Cahalan, p 126) simultaneously visualized thymocyte motility and internal Ca2+ concentration ([Ca2+],) by two-photon microscopy. A single thymocyte's migration in a thymus slice is shown. 'Cooler' colors indicate the low [Ca2+], of rapidly migrating thymocytes, whereas 'hotter' colors indicate increased [Ca2+], and thymocyte immobility. Thus, Ca2+ signals serve as a stop signal during positive selection. Art work by Lewis Long.



Meeting Report

  • Meeting Report |

    Lymphocyte lineage specification involves multiple regulatory factors that act in reciprocal fashion to ensure lineage committment and identity. New insights on how these factors interact were presented at the second Aegean Workshop on Gene Regulation in Lymphocyte Development.

    • Barbara A Osborne
    •  & Barbara L Kee

News and Views

  • News & Views |

    The definition of the physiological functions of dendritic cells is undergoing refinement, as specialization of dendritic cell labor depends on their previous encounters.

    • William R Heath
    •  & Jose A Villadangos
  • News & Views |

    Calcium signaling is essential during thymocyte development. It seems that calcium oscillations trigger thymocytes to become immotile, prolonging interactions with stromal cells that are critical for positive selection.

    • Michael D Cahalan
  • News & Views |

    It is not clear how lymphocytes establish monoallelic gene expression of antigen receptor genes. New data linking local chromatin modifications with nuclear movements provide a framework for deciphering this process.

    • Ranjan Sen
  • News & Views |

    Specific docking of the three T cell receptor complementary-determining regions (CDRs) onto the peptide-MHC complex is the basis of immune recognition. However, the contribution of each CDR to peptide-MHC binding is not routine.

    • David M Kranz