Activation of human CD4+CD45RA+ T cells by chrysotile asbestos in vitro

Our plain-English summary of Activation of human CD4+CD45RA+ T cells by chrysotile asbestos in vitro, by K. Kinugawa, A. Ueki, M. Yamaguchi, et al (Cancer Letters, 1992).

The study

• Authors: K. Kinugawa, A. Ueki, M. Yamaguchi, Y. Watanabe, Y. Kawakami, F. Hyodoh, H. Tsushima
• Journal: Cancer Letters
• Published: 1992;66(2):99-106
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Chrysotile asbestos stimulates T lymphocyte subsets. Cell surface CD4 or CD45RA expression in peripheral blood mononuclear cells (PBMC) was downregulated after incubation with chrysotile asbestos in vitro temporarily. The percentage of CD4+CD45RA+ cells and mean fluorescence intensity in CD4 or CD45RA decreased after incubation with asbestos and returned to the original level after 24 h of incubation, which suggests that chrysotile asbestos activates CD4+CD45RA+ cells. No change was observed in CD29 expression. An increased percentage of IL-2R positive cells and an elevated intracellular Ca++ level were also indicative of the activation of PBMC by chrysotile asbestos.

In plain English

This was a laboratory study of human blood cells, not a study of people exposed to asbestos. The authors took white blood cells (peripheral blood mononuclear cells) from 10 healthy volunteers and incubated them with chrysotile asbestos, a UICC standard reference sample, at 50 micrograms per millilitre for up to 48 hours. Some cells were also treated with the cell stimulant PHA. When chrysotile was added alongside PHA, the CD4 marker on cells was significantly lower than with PHA alone, and it returned to its original level within 24 hours. The CD8 marker showed no significant difference. With chrysotile alone, the percentage of CD4+CD45RA+ cells fell about 40% at 12 hours, and this change disappeared after 24 hours. The CD29 marker did not change significantly. Cells carrying the IL-2 receptor rose from 5.1% in control cells to 6.8% after 24 hours with chrysotile, and calcium levels inside the cells rose. Cell viability stayed above 90%. The authors concluded that chrysotile selectively activated the CD4+CD45RA+ subset. They suggested this may play a role in immunodeficiencies or malignant tumors seen in asbestos workers.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: In vitro laboratory experiment on human blood cells
• Who was studied: Peripheral blood mononuclear cells (PBMC) from 10 healthy volunteers; Department of Hygiene, Kawasaki Medical School, Japan; no study dates given
• Exposure: Chrysotile asbestos (UICC standard reference sample; fibres 0.21 to 0.40 micrometres in diameter and 2.01 to 4.00 micrometres long) at 50 micrograms per ml for 12 to 48 hours. Some cells also received 10 micrograms per ml PHA, alone or with chrysotile, for 1 to 48 hours.
• Main results:
  • In cells given PHA plus chrysotile, CD4 expression was significantly lower than in cells given PHA alone (P < 0.01), and it returned to the original level in 24 hours
  • No significant difference in CD8 antigen between cells given PHA alone and cells given PHA plus chrysotile
  • With chrysotile alone, the percentage of CD4+CD45RA+ cells declined about 40% at 12 hours (P < 0.01)
  • Mean fluorescence intensity of CD45RA decreased about 20%; these changes disappeared after 24 hours of incubation
  • The percentage of CD4+CD29+ cells and CD29 fluorescence intensity did not change significantly with chrysotile
  • IL-2 receptor positive cells: 5.1 plus or minus 1.2% in control cells versus 6.8 plus or minus 1.7% after 24 hours with chrysotile (P < 0.05)
  • Intracellular calcium (mean fluorescence intensity): 724 plus or minus 74 in PHA-stimulated control cells versus 362 plus or minus 21 in unstimulated cells (P < 0.01)
  • Chrysotile-treated cells also showed significantly increased intracellular calcium, with a mean fluorescence intensity of 425 plus or minus 43 (P < 0.05)
  • Cell viability stayed above 90%, with no difference between cells cultured with or without chrysotile
• The authors' conclusion: The authors concluded that chrysotile selectively activated the CD4+CD45RA+ subset. They suggested this activation may play a role in impaired lymphocyte responses and in the high incidence of immunodeficiencies or malignant tumors observed in asbestos workers.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile.

Related studies

• Polyclonal human T-cell activation by silicate in vitro — A. Ueki, M. Yamaguchi, et al. (1994)
• Activation-induced cell death in human peripheral blood lymphocytes after stimulation with silicate in vitro — T. Aikoh, A. Tomokuni, et al. (1998)
• Biological effects of asbestos fibers on human cells in vitro--especially on lymphocytes and neutrophils — A. Ueki (2001)
• Proliferation stimulating effects of chrysotile and crocidolite asbestos fibres on B lymphocyte cell lines — A. Ueki, T. Oka, et al. (1984)
• Mineral fiber-induced leukocyte activation: the role of intra- and extracellular calcium — M. Ruotsalainen, J. Naarala, et al. (1995)
• In vitro depression of human lymphocyte mitogen response (phytohaemagglutinin) by asbestos fibres — R.G. Barbers, W.W. Shih, et al. (1982)

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