My laboratory examines how specialized lineages of the immune system develop to anticipate various types of infections and to generate the correct quality of immune response. Our initial focus examined the basis of CD4 T cell development into the function helper subsets, such as TH1, TH2, TH17, and so on. Our work defined the physiological basis of instructive differentiation that occurs in response to pathogens and defined the signaling pathways and transcriptional circuits involved. Our early discovery that dendritic cells and macrophages determined the direction of T cell differentiation, by their production of cytokines such as IL-12, led us to examine how myeloid cells evolved to be the decision makers for T cell differentiation in immunity. We are currently focused on defining the developmental basis for dendritic cell diversification into the functional subsets that control induction of the various types of lymphocyte effector responses. This work has practical implications for improved immunotherapy, including vaccine design. Ongoing projects can be found by reading our recently published work and review articles.