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- Title
Lymphoproliferative disorders involving T helper effector cells with defective LAT signalosomes.
- Authors
Roncagalli, Romain; Mingueneau, Michael; Grégoire, Claude; Langlet, Christelle; Malissen, Bernard; Malissen, Marie
- Abstract
Linker for activation of T cells (LAT) is a membrane adaptor protein that is expressed in T cells and coordinates the assembly of a multiprotein complex—the LAT signalosome—that links the T cell-specific and the ubiquitous components of the T cell antigen receptor (TCR) signaling pathway. The present review focuses on recent LAT knock-in mice that were found to develop lymphoproliferative disorders involving polyclonal CD4+ T cells that produced excessive amounts of T helper-type 2 cytokines. These mouse models revealed that LAT constitutes more than just a positive regulator of TCR signaling and plays a negative regulatory role that contributes to terminate antigen-driven T cell responses by exerting a repressive function on components of the TCR signaling cassette that lie upstream of LAT or function independently of LAT. In the absence of such a LAT-operated negative regulatory loop that is intrinsic to conventional CD4+ T cells and of no lesser importance than the extrinsic regulatory mechanisms mediated by regulatory T cells, physiologic, antigen-specific CD4+ T cell responses evolve into chronic pro-inflammatory responses that perpetuate themselves in a manner that does not depend on engagement of the TCR and that induce the production of massive amounts of antibodies and autoantibodies in a major histocompatibility complex-II-independent, “quasi-mitogenic” mode. As discussed, these data underscore that a novel immunopathology proper to defective LAT signalosomes is likely taking shape, and we propose to call it “LAT signaling pathology.”
- Subjects
LYMPHOPROLIFERATIVE disorders; T cells; AUTOIMMUNITY; CYTOKINES; CD4 antigen
- Publication
Seminars in Immunopathology, 2010, Vol 32, Issue 2, p117
- ISSN
1863-2297
- Publication type
Article
- DOI
10.1007/s00281-009-0195-y