title: Induction of granzyme B and T cell cytotoxic capacity by IL-2 or IL-15 without antigens: multiclonal responses that are extremely lytic if triggered and short-lived after cytokine withdrawal.
abstract: The purpose of these studies was to determine the minimal requirements to induce granzyme B, cytotoxic granules and perforin-dependent lytic capacity. To our surprise, both IL-2 and IL-15 induced not only proliferation, but also profound granzyme B and lytic capacity from CD8+ T cells in the absence of antigen or TCR-stimulation. Mouse splenocytes were incubated with mouse r-IL-2 or r-IL-15 for three days, tested by anti-CD3 redirected lysis and examined for intracellular granzyme B and for T cell activation markers. With 10(-8) M IL-2 or IL-15, there was excellent lytic activity at 1:1 effector to target ratios mediated by T cells from wild-type but not from perforin-gene-ablated mice, consistent with multiclonal activation. Lower interleukin concentrations induced less lytic activity. Granzyme B was undetectable on day 0, and greatly elevated on day 3 in CD44hi CD8+ T cells as detected by flow cytometry. Cytokines alone elevated the granzyme B as much as concanavalin A combined with the cytokines. Some ex vivo CD8+ T cells were CD122+, as were the cultured granzyme B+ cells, thus both populations had low-affinity receptors for the interleukins. Only some of the activated cells were proliferating as detected by CFSE labeling. When the cytokines were withdrawn, the cells lost lytic activity within 24 h and then within the next 24 h, died. Our results suggest that high concentrations of either IL-2 or IL-15 will activate the lytic capacity and granzyme B expression of many T cells and that antigen recognition is not required.
authors.affiliation: Department of Microbiology and Immunology/320, University of Nevada, Reno, 1664 N. Virginia St. Reno, NV 89557, USA. david@tamang.org
authors.forename: David L
authors.initials: DL
authors.lastname: Tamang
authors.forename: Doug
authors.initials: D
authors.lastname: Redelman
authors.forename: Bryce N
authors.initials: BN
authors.lastname: Alves
authors.forename: Leanne
authors.initials: L
authors.lastname: Vollger
authors.forename: Christy
authors.initials: C
authors.lastname: Bethley
authors.forename: Dorothy
authors.initials: D
authors.lastname: Hudig
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D040881:CD11a Antigen / Q000378:metabolism; D018801:CD2 Antigens / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic / Q000187:drug effects* / Q000276:immunology; D005434:Flow Cytometry; D053804:Granzymes / Q000378:metabolism*; D018960:Hyaluronan Receptors / Q000378:metabolism; D060889:Inducible T-Cell Co-Stimulator Protein; D019409:Interleukin-15 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D053646:Interleukin-2 Receptor beta Subunit / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D011971:Receptors, Immunologic / Q000378:metabolism; D055607:Receptors, Natural Killer Cell; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology / Q000378:metabolism
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D040881:CD11a Antigen; D018801:CD2 Antigens; C476399:Cd44 protein, mouse; D018960:Hyaluronan Receptors; C556694:Icos protein, mouse; C508022:Il2rb protein, mouse; D060889:Inducible T-Cell Co-Stimulator Protein; D019409:Interleukin-15; D007376:Interleukin-2; D053646:Interleukin-2 Receptor beta Subunit; D011971:Receptors, Immunologic; D055607:Receptors, Natural Killer Cell; D053804:Granzymes; C509214:Gzmb protein, mouse