Abstract
Mucosal immune tolerance in the healthy intestine is typified by lamina propria T cell (LPT) functional hyporesponsiveness after TCR engagement when compared with peripheral blood T cell (PBT). When LPT from an inflamed intestine are activated through TCR cross-linking, their responsiveness is stronger. LPT are thus capable of switching from a tolerant to a reactive state, toggling between high and low thresholds of activation. We demonstrate that in normal LPT global tyrosine phosphorylation upon TCR cross-linking or an increase in intracellular H2O2, an inhibitor of protein tyrosine phosphatases, is muted. Thus, we propose that LPT have a greater reducing capacity than PBT, shifting the balance between kinases and protein tyrosine phosphatases in favor of the latter. Surface γ-glutamyl transpeptidase, an indirect indicator of redox potential, and glutathione are significantly elevated in LPT compared with PBT, suggesting that elevated glutathione detoxifies TCR-induced reactive oxygen species. When glutathione is depleted, TCR-induced LPT tyrosine phosphorylation rises to PBT levels. Conversely, increasing glutathione in PBT attenuates tyrosine phosphorylation. In LPT isolated from inflamed mucosa, TCR cross-linking induces greater phosphorylation, and γ-glutamyl transpeptidase levels are reduced compared with those from autologous noninflamed tissue. We conclude that the high TCR signaling threshold of mucosal T cells is tuned by intracellular redox equilibrium, whose dysregulation may mediate intestinal inflammation.
| Original language | English |
|---|---|
| Pages (from-to) | 2158-2166 |
| Number of pages | 9 |
| Journal | Journal of Immunology |
| Volume | 175 |
| Issue number | 4 |
| Publication status | Published - Aug 15 2005 |
Fingerprint
ASJC Scopus subject areas
- Immunology
Cite this
Redox equilibrium in mucosal T cells tunes the intestinal TCR signaling threshold. / Reyes, Brenda M Rivera; Danese, Silvio; Sans, Miquel; Fiocchi, Claudio; Levine, Alan D.
In: Journal of Immunology, Vol. 175, No. 4, 15.08.2005, p. 2158-2166.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Redox equilibrium in mucosal T cells tunes the intestinal TCR signaling threshold
AU - Reyes, Brenda M Rivera
AU - Danese, Silvio
AU - Sans, Miquel
AU - Fiocchi, Claudio
AU - Levine, Alan D.
PY - 2005/8/15
Y1 - 2005/8/15
N2 - Mucosal immune tolerance in the healthy intestine is typified by lamina propria T cell (LPT) functional hyporesponsiveness after TCR engagement when compared with peripheral blood T cell (PBT). When LPT from an inflamed intestine are activated through TCR cross-linking, their responsiveness is stronger. LPT are thus capable of switching from a tolerant to a reactive state, toggling between high and low thresholds of activation. We demonstrate that in normal LPT global tyrosine phosphorylation upon TCR cross-linking or an increase in intracellular H2O2, an inhibitor of protein tyrosine phosphatases, is muted. Thus, we propose that LPT have a greater reducing capacity than PBT, shifting the balance between kinases and protein tyrosine phosphatases in favor of the latter. Surface γ-glutamyl transpeptidase, an indirect indicator of redox potential, and glutathione are significantly elevated in LPT compared with PBT, suggesting that elevated glutathione detoxifies TCR-induced reactive oxygen species. When glutathione is depleted, TCR-induced LPT tyrosine phosphorylation rises to PBT levels. Conversely, increasing glutathione in PBT attenuates tyrosine phosphorylation. In LPT isolated from inflamed mucosa, TCR cross-linking induces greater phosphorylation, and γ-glutamyl transpeptidase levels are reduced compared with those from autologous noninflamed tissue. We conclude that the high TCR signaling threshold of mucosal T cells is tuned by intracellular redox equilibrium, whose dysregulation may mediate intestinal inflammation.
AB - Mucosal immune tolerance in the healthy intestine is typified by lamina propria T cell (LPT) functional hyporesponsiveness after TCR engagement when compared with peripheral blood T cell (PBT). When LPT from an inflamed intestine are activated through TCR cross-linking, their responsiveness is stronger. LPT are thus capable of switching from a tolerant to a reactive state, toggling between high and low thresholds of activation. We demonstrate that in normal LPT global tyrosine phosphorylation upon TCR cross-linking or an increase in intracellular H2O2, an inhibitor of protein tyrosine phosphatases, is muted. Thus, we propose that LPT have a greater reducing capacity than PBT, shifting the balance between kinases and protein tyrosine phosphatases in favor of the latter. Surface γ-glutamyl transpeptidase, an indirect indicator of redox potential, and glutathione are significantly elevated in LPT compared with PBT, suggesting that elevated glutathione detoxifies TCR-induced reactive oxygen species. When glutathione is depleted, TCR-induced LPT tyrosine phosphorylation rises to PBT levels. Conversely, increasing glutathione in PBT attenuates tyrosine phosphorylation. In LPT isolated from inflamed mucosa, TCR cross-linking induces greater phosphorylation, and γ-glutamyl transpeptidase levels are reduced compared with those from autologous noninflamed tissue. We conclude that the high TCR signaling threshold of mucosal T cells is tuned by intracellular redox equilibrium, whose dysregulation may mediate intestinal inflammation.
UR - http://www.scopus.com/inward/record.url?scp=23444454873&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=23444454873&partnerID=8YFLogxK
M3 - Article
C2 - 16081782
AN - SCOPUS:23444454873
VL - 175
SP - 2158
EP - 2166
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 4
ER -