Critical roles of Bim in T cell activation and T cell-mediated autoimmune inflammation in mice

Maciej W. Ludwinski, Jing Sun, Brendan Hilliard, Shunyou Gong, Fan Xue, Ruaidhri J. Carmody, Jennifer DeVirgiliis, Youhai H. Chen

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Bim, the B cell lymphoma 2-interacting (Bcl2-interacting) mediator, maintains immunological tolerance by deleting autoreactive lymphocytes through apoptosis. We report here that Bim is also, paradoxically, required for the activation of autoreactive T cells. Deletion of Bim in hematopoietic cells rendered mice resistant to autoimmune encephalomyelitis and diabetes, and Bim-deficient T cells had diminished cytokine production. Upon T cell receptor activation, Bim-deficient T cells exhibited severe defects in both calcium release and dephosphorylation of nuclear factor of activated T cells (NFAT) but maintained normal levels of activation of NF-κB and MAPKs. The defective calcium signaling in Bim-deficient T cells was associated with a significant increase in the formation of an inhibitory complex containing Bcl2 and the inositol triphosphate receptor (IP3R). Thus, in addition to mediating the death of autoreactive T cells, Bim also controlled T cell activation through the IP3R/calcium/NFAT pathway. These results indicate that a single protein is used to control both the activation and apoptosis of autoreactive T cells and may explain why Bim-deficient mice do not reject their own organs despite lacking thymic negative selection.

Original languageEnglish (US)
Pages (from-to)1706-1713
Number of pages8
JournalJournal of Clinical Investigation
Issue number6
StatePublished - Jun 1 2009

ASJC Scopus subject areas

  • Medicine(all)


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