title: Protective activity of adult T cell leukemia-derived factor (ADF) against tumor necrosis factor-dependent cytotoxicity on U937 cells.
abstract: Adult T cell leukemia-derived factor (ADF) is a human homologue of thioredoxin with many biologic functions including IL-2R induction, growth promotion, thiol-dependent reducing activity, and radical scavenging activity. The regulatory effect of ADF on the cytotoxic activity of TNF was examined by using a human histiocytic lymphoma cell line, U937. When U937 cells were preincubated with recombinant ADF (rADF) (0.1-100 micrograms/ml) at 37 degrees C for 30 min, TNF-dependent cytotoxicity on U937 cells was markedly inhibited. This inhibitory effect was as high as 95% in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (rADF 100 micrograms/ml) and 85% in the 51Cr-releasing assay (rADF 10 micrograms/ml). After pretreatment of U937 cells with IFN-gamma to augment the sensitivity to TNF, an inhibitory effect of rADF was also found. When U937 cells were washed after preincubation with rADF, resistance to TNF-dependent cytotoxicity was still observed, indicating that rADF inhibited the sensitivity of U937 to TNF-dependent cytotoxicity rather than modifying TNF molecules. Scatchard analysis of TNF receptors on U937 cells using 125I-TNF showed that rADF modulated neither the density nor the affinity of the cell membrane significantly. rADF also reduced the cytotoxicity induced by anti-Fas IgM mAb which shows cytotoxicity quite similar to TNF. rADF (10 micrograms/ml) reduced 90% of the cytotoxicity by anti-Fas IgM mAb, without a detectable change either in Fas Ag expression (MFI 58.1 vs 53.3) or in the degradation of anti-Fas IgM mAb as determined by flow cytometric analysis. These findings indicated that the rADF-induced resistance to the cytotoxic effect of TNF and anti-Fas mAb was not related to the modulation of the TNF receptor or Fas Ag.
authors.affiliation: Institute for Virus Research, Kyoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Matsuda
authors.forename: H
authors.initials: H
authors.lastname: Masutani
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
authors.forename: S
authors.initials: S
authors.lastname: Miyajima
authors.forename: A
authors.initials: A
authors.lastname: Yamauchi
authors.forename: S
authors.initials: S
authors.lastname: Yonehara
authors.forename: A
authors.initials: A
authors.lastname: Uchida
authors.forename: K
authors.initials: K
authors.lastname: Irimajiri
authors.forename: A
authors.initials: A
authors.lastname: Horiuchi
authors.forename: J
authors.initials: J
authors.lastname: Yodoi
mesh_terms: D000954:Antigens, Surface / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects; D016207:Cytokines; D006801:Humans; D066298:In Vitro Techniques; D009363:Neoplasm Proteins / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D019014:fas Receptor
chemical_list: D000954:Antigens, Surface; D016207:Cytokines; D009363:Neoplasm Proteins; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C055533:adult T cell leukemia-derived factor; D019014:fas Receptor; D013879:Thioredoxins; D013880:Thioredoxin-Disulfide Reductase