Control of T Helper 2 Cell Function and Allergic Airway Inflammation by PKCζ

Asthma is a disease of chronic airway inflammation in which T helper (Th) 2 cells play a critical role. The molecular mechanisms controlling Th2 differentiation and function are of paramount importance in biology and immunology. PKCζ has been implicated in the regulation of apoptosis and NF-κB, as well as in the control of T-dependent responses, although no defects were detected in naïve T cells from PKCζ -/- mice. Here, we report that PKCζ is critical for IL-4 signaling and Th2 differentiation. Thus, PKCζ levels are increased during Th2 differentiation, but not Th1 differentiation, of CD4+ T cells, and the loss of PKCζ impairs the secretion of Th2 cytokines in vitro and in vivo, as well as the nuclear translocation and tyrosine phosphorylation of Stat6 and Jak1 activation, essential downstream targets of IL-4 signaling. Moreover, PKCζ -/- mice display dramatic inhibition of ovalbumin-induced allergic airway disease, strongly suggesting that PKCζ can be a therapeutic target in asthma.