T cell stimulation in the absence of exogenous antigen: a T cell signal is induced by both MHC-dependent and -independent mechanisms

✍ Scribed by Matthew Bettini; Hongkang Xi; Gilbert J. Kersh

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 244 KB
• Volume: 33
• Category: Article
• ISSN: 0014-2980
• DOI: 10.1002/eji.200324067

✦ Synopsis

Abstract

Mature T cells residing in peripheral lymphoid organs have frequent contact with antigen presenting cells (APC). Such contact may be required for T cell survival, but the degree to which signals in mature T cells are induced by TCR recognition of self peptide/MHC complexes is unclear. We have used induction of the early growth response gene 1 (Egr1) as an indicator of signal transductionin 3.L2 (I‐E^k^‐restricted) T cells interacting with APC in the absence of exogenous antigen. The data show that Egr1 can be induced in 3.L2 T cells by TCR recognition of self peptides presented by I‐E^k^. However, a more transient induction of Egr1 can be induced in 3.L2 T cells interacting with dendritic cells derived from class II/β2m double‐deficient mice. Egr1 inductionafter T cell‐APC contact was also observed in a freshly isolated polyclonal CD4 T cell population. The data suggest that self peptide/MHC recognition by the TCR induces a signal in T cells and that dendritic cells can also induce a more transient T cell signal by an MHC‐independent mechanism.