Redox regulation of lymphocyte signaling

Compelling evidence exists that reactive oxygen species can deliver intrace llular signals in mammalian cells, and elicit a broad array of physiologica l responses according to the cell type, the oxidative burden and the cellul ar compartment where radicals are generated. When applied to immune cells, these concepts gain a particular relevance, in relation to the plasticity o f immune functions and the biological complexity of lymphocyte response to antigens, Here we review some recent and somehow conflicting observations o n the involvement of oxygen radicals and redox balance in lymphocyte activa tion, and propose models for how radical species could contribute to normal and pathological immunity.