This research unit’s long-term objective is to understand the developmental mechanism of T cells and the role they play. The development of T cells is a complex, multi-step process, a critical element of which is the T cell receptor CD3 complex (TCR/CDD3). Its components play a primordial role in signal transduction that leads to positive or negative selection of developing T cells. In order to understand the process of thymic selection and differentiation, Vibhuti Dave has chosen two mouse models, the CD3d-deficient and the “Helper Deficient” (HD) mouse model. He is currently working on defining the role of CD3d in thymic selection, using a transgenic approach, as well as mapping and identification of the gene responsible for the HD phenotype. Future projects will focus on the identification of other molecules involved in thymic selection and differentiation.