In vitro generated CD4 cell lines and effectors often produce either Th1 or Th2 cytokines, but stimulation of resting CD4 cells from animals leads to production mostly of IL-2. To determine whether polarization of CD4 effector cells results in development of polarized memory, I generated antigen-specific Th1 and Th2 effectors in vitro and transferred them to adoptive hosts. The effectors gave rise to long-lived populations of CD4 T cells with the phenotype of resting memory cells. Recovered cells responded vigorously to specific antigen, producing a pattern of cytokines closely related to that of the transferred effectors. Thus, encounter with a peptide antigen and directive cytokines at the initiation of culture can lead to generation of both effector and long-lived memory cell populations that produce restricted patterns of cytokines.