Are differentiated human T helper cells reversible?

Cytokines and cytokine antagonists have important roles in controlling the type of immune response generated. These mediators have the most profound effects if used at the initiation of an immune response. For example, IL-4 and IL-12 are important determinants in the generation of Th1 and Th2 cells, respectively, in both murine and human systems. One critical question that relates to human pathogenesis is whether Th1- and Th2-type cells can be altered after disease is initiated. Data will be presented showing how cytokines can change the types of cytokines produced from established Th1 and Th2 cells. Moreover, intracellular staining of cytokines was done to more accurately define whether cytokine production was altered on a single cell basis. These studies may have implications for immune manipulation for established allergic or autoimmune diseases.