Generation and in vivo persistence of polarized Th1 and Th2 memory cells.

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.