Mice lacking both the p110gamma and p110delta isoforms display severe impairment of thymocyte development. Here, we show that this phenotype is recapitulated in p110gamma-/-/p110delta(D910A/D910A) (p110gamma(KO)delta(D910A)) mice where the p110delta isoform has been inactivated by a point mutation. Moreover, we have examined the pathological consequences of the p110gammadelta deficiency, which include profound T-cell lymphopenia, T-cell and eosinophil infiltration of mucosal organs, elevated IgE levels, and a skewing toward Th2 immune responses. Using small-molecule selective inhibitors, we demonstrated that in mature T cells, p110delta, but not p110gamma, controls Th1 and Th2 cytokine secretion. Thus, the pathology in the p110gammadelta-deficient mice is likely to be secondary to a developmental block in the thymus that leads to lymphopenia-associated inflammatory responses.
Inactivation of PI3Kgamma and PI3Kdelta distorts T-cell development and causes multiple organ inflammation
HIRSCH, Emilio;
2007-01-01
Abstract
Mice lacking both the p110gamma and p110delta isoforms display severe impairment of thymocyte development. Here, we show that this phenotype is recapitulated in p110gamma-/-/p110delta(D910A/D910A) (p110gamma(KO)delta(D910A)) mice where the p110delta isoform has been inactivated by a point mutation. Moreover, we have examined the pathological consequences of the p110gammadelta deficiency, which include profound T-cell lymphopenia, T-cell and eosinophil infiltration of mucosal organs, elevated IgE levels, and a skewing toward Th2 immune responses. Using small-molecule selective inhibitors, we demonstrated that in mature T cells, p110delta, but not p110gamma, controls Th1 and Th2 cytokine secretion. Thus, the pathology in the p110gammadelta-deficient mice is likely to be secondary to a developmental block in the thymus that leads to lymphopenia-associated inflammatory responses.
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