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Activation of cytotoxic lymphocytes by interferon‐α: role of oxygen radical‐producing mononuclear phagocytes
Author(s) -
Hansson Markus,
Romero Ana,
Thorén Fredrik,
Hermodsson Svante,
Hellstrand Kristoffer
Publication year - 2004
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0204113
Subject(s) - biology , cytotoxic t cell , reactive oxygen species , immunology , peripheral blood mononuclear cell , phagocyte , cd3 , lymphocyte , interferon , immune system , microbiology and biotechnology , in vitro , cd8 , biochemistry
A significant part of the therapeutic benefit of interferon‐α (IFN‐α) therapy in malignant diseases and in chronic viral infections is assumed to result from activation of lymphocytes with natural killer (NK) and T cell phenotype. In tumor tissue and in chronically infected tissue, the function and viability of these lymphocytes are frequently impaired. Mononuclear phagocyte (MP)‐derived reactive oxygen species (ROS) have been proposed to contribute to the lymphocyte suppression in these tissues. Here, we report that three types of human cytotoxic lymphocytes of relevance to immunoactivation by IFN‐α, CD3ɛ + /8 + /56 – T cells, CD3ɛ – /56 + NK cells, and CD3ɛ +/ 56 + NK/T cells became anergic to IFN‐α induction of the cell‐surface activation marker CD69 after exposure to autologous MPs in vitro. In addition to their incapacity to express CD69, cytotoxic lymphocytes acquired features characteristic of apoptosis after incubation with MPs. The lymphocyte apoptosis and nonresponsiveness to IFN‐α were prevented by two inhibitors of reduced nicotinamide adenine dinucleotide phosphate oxidase‐dependent formation of ROS in MPs, histamine dihydrochloride and diphenylene ionodonium, as well as by catalase, a scavenger of ROS. We conclude that MP‐derived ROS may negatively affect IFN‐α‐induced immunostimulation and propose that ROS inhibitors or scavengers may be useful to improve lymphocyte activation during treatment with IFN‐α.