During thymocyte development,, T-cell receptor (TCR) alpha beta-mediated in
tracellular signals can elicit two entirely different cellular responses: p
ositive selection (resulting in rescue from death and maturation or differe
ntiation) and negative selection (induction of apoptosis). Here, Hiroshi Na
kajima and colleagues discuss how survival signals that ave dependent on th
e common cytokine receptor gamma drain (gamma(c)) might affect the TCR-driv
en selection process in thymocytes, underscoring the potential role of cyto
kines in this process.