NF-κB in Th2 cells : delayed and long-lasting induction through the TCR complex

Nucelar NFκB was analyzed in murine Th2 cells after stimulation via the TCR pathway. Signals delivered through the TCR/CD3 complex induced active NFκB translocation to the nucleus of Th2 cells after a late phase (24 h) of the activation process, which is in contrast to the rapid appearance of nuclear NFκB (3 h) in Th1 cells after the same stimulation. The slow kinetic of NFκB nuclear uptake in Th2 cells was not accelerated by CD28 triggering or under stimulation with antigen plus antigen-presenting cells. Th1 and Th2 cells were also different in the composition of NFκB complexes induced. Whereas in Th1 cells TCR triggering induced the presence of nuclear p50.p65 heterodimers, in Th2 cells the complexes induced were shown to be composed of p65 plus another NFκB protein distinct from p50. The delayed NFκB induction in Th2 cells was dependent on protein synthesis and the significance of this is discussed.