title: Antigen-independent activation of naive and memory resting T cells by a cytokine combination.
abstract: We investigated whether human resting T cells could be activated to proliferate and display effector function in the absence of T cell receptor occupancy. We report that combination of interleukin 2 (IL-2), tumor necrosis factor alpha, and IL-6 activated highly purified naive (CD45RA+) and memory (CD45RO+) resting CD4+ T cells to proliferate. Under this condition, memory resting T cells could also display effector function as measured by lymphokine synthesis and help for immunoglobulin production by B cells. This novel Ag-independent pathway of T cell activation may play an important role in vivo in recruiting effector T cells at the site of immune response and in maintaining the clonal size of memory T cells in the absence of antigenic stimulation. Moreover, cytokines can induce proliferation of naive T cells without switch to memory phenotype and this may help the maintenance of the peripheral pool of naive T cells.
authors.affiliation: Immunobiology Research Institute Siena, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Unutmaz
authors.forename: P
authors.initials: P
authors.lastname: Pileri
authors.forename: S
authors.initials: S
authors.lastname: Abrignani
mesh_terms: D006801:Humans; D007156:Immunologic Memory; D007376:Interleukin-2 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D017493:Leukocyte Common Antigens / Q000032:analysis; D008213:Lymphocyte Activation / Q000187:drug effects*; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D007376:Interleukin-2; D015850:Interleukin-6; D015375:Receptors, Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D017493:Leukocyte Common Antigens