Essential role for Vav1 in activation, but not development, of gd T cells

Vav1 is a guanine nucleotide exchange factor essential in the development and function of ab lineage T cells. Here we report that in contrast to profound effects on pre-TCRor ab TCRdependent events in thymocyte development, Vav1 de®ciency has no detectable effect on the development of gd T cells. Strikingly, however, these gd T cells are markedly de®cient in signaling through the gd TCR, as evidenced by a lack of proliferation and cytokine production in response to stimulation with anti-gd TCR antibodies. We propose that Vav1 has a unique and non-redundant role in the initiation of signaling downstream of the gd TCR in lymphocytes.