title: Programming perpetual T helper cell plasticity.
abstract: In this issue of Immunity,Lee et al. (2009) and Wei et al. (2009) each investigate the stability of T helper cell lineages and find that commitment to these fates is more plastic than previously appreciated.
authors.affiliation: Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Rowell
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Wilson
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D019070:Cell Lineage / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D008213:Lymphocyte Activation; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*