Dr. Steve Hedrick’s career has focused on the immunobiology of T cells, and for many years this has entailed extensive use of mouse genetics. At the inception of transgenic mouse technology, Hendrick set up a free-standing transgenic/knockout facility for my laboratory, which became the UCSD Knockout core. Hendrick helped create some of the first T cell clones, and characterized some antigen-specific T cell clones that were used to clone the beta-chain of the T cell antigen receptor. In Hendrick lab, he analyzed an extensive set of T cell clones to unravel the basis of antigen and MHC specificity in the TCR—showing that the 3rd CDRs were important for peptide specificity. His lab has studied the development of T cells, signaling in T cells, and the conceptual basis for T cell differentiation. More recently, Hendrick has become interested in reprogramming T cells for use in immunotherapy, and this was recognized by the recent award of a Director’s Transformative Grant to study the use of Active Genetics in somatic cells.