The principal topics of the Paul laboratory are the study of the mechanisms of action and biologic functions of type I cytokines, principally IL-4 and IL-13; regulation of CD4+ T-cell differentiation, function, and plasticity; transcriptional networks underlying CD4 T-cell differentiation; strategies to enhance primary and secondary immune responses; new approaches to vaccine development; dynamics of naïve and memory lymphocyte populations during homeostatic conditions and in response to antigenic stimulation; and induction and maintenance of immunologic memory.