title: Generation of activated killer (AK) cells by recombinant interleukin 2 (rIL 2) in collaboration with interferon-gamma (IFN-gamma).
abstract: Activation of human peripheral blood mononuclear cells (PBMC) by interleukin 2 (IL 2) and the role of interferon-gamma (IFN-gamma) in the IL 2-induced activation were investigated. Activated killer (AK) cells against NK-resistant tumor cell lines were induced in the medium containing recombinant IL 2 (rIL 2) and autologous serum without any other stimulating agents. AK activity was induced by doses of rIL 2 as low as 3 U/ml, and reached a maximum at 10(3) U/ml. Incubation of PBMC with rIL 2 resulted in IFN-gamma production and augmented NK activity after 1 day of culture, and in induction of AK cells and proliferative response after 2 days of culture. These results suggested that endogenous IFN-gamma was required for rIL 2-induction of AK cells and proliferative response. To prove this, PBMC were cultured with rIL 2 and rIFN-gamma or were pretreated with rIFN-gamma before culture with rIL 2. Both rIFN-gamma treatments of PBMC augmented rIL 2-induced AK activity and proliferative response. rIL 2-induced IFN-gamma production was also enhanced by the rIFN-gamma pretreatment of PBMC. The addition of anti-IFN-gamma antibody to rIL 2 cultures abrogated the rIL 2-induced NK augmentation, AK generation, and proliferative response in proportion to the decreased amounts of endogenous IFN-gamma detectable in culture. rIFN-gamma and/or rIL 2 cultures of PBMC increased Tac antigen expression on cell surfaces as measured by flow cytometry. Enhanced Tac expression by rIL 2 was abrogated by adding anti-IFN-gamma antibody. These data indicate that: 1) AK generation and IFN-gamma production are mediated by IL 2, and 2) IFN-gamma production may be required for IL 2 induction of AK cells and proliferative response. These finding are consistent with the hypothesis that AK generation involves a collaboration between IL 2 and IFN-gamma, in which IL 2 stimulates PBMC to produce IFN-gamma, which in turn acts as a differentiation signal that may be involved in the IL 2-initiated AK generation and proliferative response.
authors.forename: K
authors.initials: K
authors.lastname: Itoh
authors.forename: K
authors.initials: K
authors.lastname: Shiiba
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
authors.forename: R
authors.initials: R
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Kumagai
mesh_terms: D000906:Antibodies / Q000502:physiology; D000954:Antigens, Surface / Q000032:analysis; D001667:Binding, Competitive; D003602:Cytotoxicity, Immunologic; D004357:Drug Synergism; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology*; D007376:Interleukin-2 / Q000235:genetics / Q000502:physiology*; D007694:Killer Cells, Natural / Q000276:immunology*; D007700:Kinetics; D008213:Lymphocyte Activation; D011995:Recombination, Genetic; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
chemical_list: D000906:Antibodies; D000954:Antigens, Surface; D007376:Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D007371:Interferon-gamma