We are interested in the role of Tyrosine Kinases (TKs) in regulating the immune response, with the goal of using this information to manipulate immune responses. We are specifically interested in the Tec families of non-receptor TKs. Itk is a member of the Tec family of tyrosine kinases that is activated downstream of the T cell receptor, or chemokine receptors. Mice lacking Itk exhibit defects in T-cell development, as well as T cell differentiation. Understanding the specific downstream activities of these kinases is crucial to understanding how they impact lymphoid activation and development.