T cell tyrosine phosphorylation response to transient redox stress

Reactive Oxygen Species (ROS) are crucial to multiple biological processes involved in the pathophysiology of in-
flammation, and are also involved in redox signaling responses. Although previous reports have described an association
between oxidative events and the modulation of innate immunity, a role for redox signaling in T cell
mediated adaptive immunity has not been described yet. This work aims at assessing if T cells can sense redox
stress through protein sulfhydryl oxidation and respond with tyrosine phosphorylation changes. Our data
show that Jurkat T cells respond to –SH group oxidation with specific tyrosine phosphorylation events. The release
of T cell cytokines TNF, IFNγ and IL2 as well as the expression of a number of receptors are affected by
those changes. Additionally, experiments with spleen tyrosine kinase (Syk) inhibitors showed a major involvement
of Syk in these responses. The experiments described herein show a link between cysteine oxidation and
tyrosine phosphorylation changes in T cells, as well as a novel mechanism by which Syk inhibitors exert their
anti-inflammatory activity through the inhibition of a response initiated by ROS.