Effects of environmental substance on the human immune system - Reduction of tumor immunity induced by asbestos exposure

Naoko Kumagai, Megumi Maeda, Hidenori Matsuzaki, Suni Lee, Yasumitsu Nishimura, Takemi Otsuki

Research output: Contribution to journalArticlepeer-review


Similar to the silica which causes dysregulation of autoimmunity as well as pulmonary fibrosis, asbestos, which is mineral silicate including iron, magnesium or calcium attached to the core silica molecule, SiO2 may affect the human immune system. Considering malignant complications of asbestos-exposed patients such as mesothelioma and lung cancer, asbestos is assumed to lower tumor immunity. The effects of asbestos on tumor immunity have been investigated with this in mind. It was found that natural killer (NK) cell activity was reduced in correspondence with the surface expression level of NKp46, one of the activating receptors of the NK cell. The proliferation and differentiation of cytotoxic T lymphocytes (CTL) were inhibited during induction of effector/memory CTL from naïve CD8+ T cells by culturing with allo-antigen supplemented with chrysotile-asbestos. In addition, tumor immunity-related molecules such as interferon (IFN) -γ and the CXCR3 chemokine receptor, were reduced by asbestos exposure using the T cell line, MT-2. Furthermore, activation-inhibitory functions such as the CD4 +CD25+FoxP3+ regulatory T cell possessing the MT-2 cell line, was enhanced by asbestos exposure. All of these findings suggested that asbestos exposure lowered tumor immunity. In addition, some of these findings were confirmed in asbestos-exposed patients. Reduction of tumor immunity caused by exposure to asbestos may make it easier to develop asbestos-inducing malignant tumors in the patients with asbestos exposure.

Original languageEnglish
Pages (from-to)739-746
Number of pages8
Issue number4
Publication statusPublished - Jul 30 2011
Externally publishedYes


  • Asbestos
  • CTL
  • NK cell
  • Regulatory T cell
  • Tumor immunity

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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