Inhibition of natural killer activity by tumor-associated lymphoid cells from ascites ovarian carcinomas

P. Allavena, M. Introna, C. Mangioni, A. Mantovani

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Tumor-associated lymphocytes (TAL) were isolated from ascites ovarian tumors by stepwise application of density and velocity sedimentation on discontinuous Ficoll-Hypaque gradients and fetal bovine serum. TAL had low levels of natural killer (NK) activity compared to levels of peripheral blood lymphocytes (PBL) from the same patients or control subjects. When TAL were mixed with PBL, significant inhibition of NK activity was observed in 7 of 27 patients tested, with the suppression levels ranging from 14 to 60%. Inhibition of PBL NK activity was observed at the ratio of TAL to PBL of 1:1 or 2:1. Suppression of NK activity was detected with effector-to-target cell ratios ranging from 6:1 to 25:1 and at incubation times from 4 to 20 hours in the cytolysis assay. Tumor-associated macrophages from 6 patients were tested for suppression of NK activity. Only with 1 donor was a 17% inhibition observed at a ratio of macrophages to PBL of 1:1. Thus suppression by mature plastic adherent macrophages does not play a major role in the determination of the low levels of NK in human ascites ovarian tumors and the inhibitory activity of suppressor TAL, which had a minor contamination (

Original languageEnglish
Pages (from-to)319-325
Number of pages7
JournalJournal of the National Cancer Institute
Issue number2
Publication statusPublished - 1981


ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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