Ca2+ signals and T lymphocytes new mechanisms and functions in Ca2+ signalling

Interaction between a T cell and an antigen-presenting cell leads to the rapid formation of an immunological synapse allowing antigen detection by the T cell and the development of an immune response. Antigen detection triggers various cellular responses including a modest but sustained T cell Ca2+ increase. In this review are discussed a series of related questions. What are the various molecular events by which a T cell Ca2+ response can be triggered in the immunological synapse by a very small amount of antigen ? How is Ca2+ released from intracellular stores and how can these stores remain empty for hours ? Through which channels does Ca2+ influx takes place, and how is Ca2+ influx coupled to Ca2+ release from intracellular stores ? What are the main immediate and indirect cellular targets of the Ca2+ increase ? (C) 2003 Elsevier SAS. All rights reserved.