Asbestos-induced alterations of human lymphoid cell mitogenic responses

Our plain-English summary of Asbestos-induced alterations of human lymphoid cell mitogenic responses, by B.E. Bozelka, H.R. Gaumer, J. Nordberg, et al (Environmental Research, 1983).

The study

• Authors: B.E. Bozelka, H.R. Gaumer, J. Nordberg, J.E. Salvaggio
• Journal: Environmental Research
• Published: 1983;30(2):281-90
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Using mitogenic assays, we have investigated the short term effects of two asbestos (amosite and chrysotile) fibers on lymphocyte functions in vitro. These oppositely charged fibers produced different alterations in mitogenesis. The blastogenic responses of concanavalin-A (Con-A) and pokeweed mitogen stimulated human peripheral blood mononuclear cells (PBMN) were significantly increased by the inclusion of 6 micrograms of chrysotile to the culture media. Amosite fibers proved to be inhibitory in all tests. When PBMN were depleted of monocytes, asbestos-related alterations of Con-A responsiveness were unchanged among the remaining cells. However, the addition of chrysotile to phytohemagglutinin (PHA) cultures resulted in a significant increase of the mitogenic response. When PBMN were enriched for T lymphocytes, and again cultured with the mitogens and fibers, the Con-A response still displayed impressive enhancement with chrysotile. In contrast to an intact PBMN population, PHA-induced blastogenesis among these T-enriched lymphocytes was significantly elevated. These experiments demonstrate that asbestos can induce significant changes in the functional integrity of PBMN following a relatively short exposure time in culture.

In plain English

This laboratory study tested how two types of asbestos, amosite and chrysotile, affected human white blood cells in culture. The cells were mononuclear cells taken from the blood of healthy donors aged 21 to 35. The authors stimulated the cells with three substances that make lymphocytes multiply (concanavalin-A, pokeweed mitogen and phytohemagglutinin). They then measured how much the cells multiplied with and without UICC asbestos fibers added. Chrysotile at 6 micrograms per well significantly increased the response to concanavalin-A (P = 0.001) and pokeweed mitogen (P = 0.05), but not to phytohemagglutinin. Amosite at 22 micrograms per well was inhibitory, particularly with phytohemagglutinin (P = 0.05). Amosite killed lymphocytes above 200 micrograms per well, and chrysotile was toxic above 40 micrograms per well. In cells enriched for T lymphocytes, chrysotile significantly increased the concanavalin-A response, in one experiment to 512% of the control response (about five times). It also significantly increased the phytohemagglutinin response, while amosite suppressed responses. Removing monocytes did not change the concanavalin-A results. The authors concluded that chrysotile significantly altered these responses in the laboratory, and stated that the relevance to human disease can only be hypothesized at this time.

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 (mitogen stimulation assays)
• Who was studied: Peripheral blood mononuclear cells from normal healthy donors aged 21 to 35, studied at Tulane University School of Medicine, New Orleans. The authors also tested cells enriched for T lymphocytes and cells depleted of monocytes. The number of donors is not stated.
• Exposure: UICC amosite and chrysotile asbestos fibers, mostly 5 to 75 micrometers long, were added to cultures. Chrysotile was used mainly at 6 micrograms per well and amosite at 22 micrograms per well, and a range of doses was also tested. Glasswool, microfibers and mineral-wool fibers were used as controls.
• Main results:
  • In whole mononuclear cell cultures, chrysotile (6 micrograms per well) significantly increased the response to concanavalin-A (P = 0.001) and to pokeweed mitogen (P = 0.05).
  • In whole mononuclear cell cultures, no significant change in the phytohemagglutinin response was detected.
  • Amosite (22 micrograms per well) inhibited mitogen-stimulated lymphocytes, particularly in phytohemagglutinin cultures (P = 0.05).
  • Among the control fibers, microfibers increased the pokeweed mitogen response only at very high fiber concentrations.
  • Stimulation of the concanavalin-A response peaked at 6 micrograms of chrysotile per well. Amosite was not stimulatory at any concentration examined and was toxic to lymphocytes above 200 micrograms per well.
  • Chrysotile was significantly toxic to the cells at levels above 40 micrograms per well.
  • In cultures enriched for T lymphocytes, chrysotile significantly enhanced the concanavalin-A response (P = 0.001) in all three experiments. In Experiment I the response was 71,818 cpm with chrysotile versus 14,017 cpm with mitogen alone, which is 512% of the control response (about five times). The authors' text describes this as an increase of 'as much as 500%'.
  • In enriched T lymphocytes, chrysotile significantly enhanced the phytohemagglutinin response, while amosite-treated cultures showed suppressed responses.
  • Removing monocytes (leaving 2.5% phagocytic cells) did not change the concanavalin-A response of chrysotile- or amosite-treated cultures.
  • Monocyte-depleted cells stimulated with phytohemagglutinin and treated with chrysotile showed a significant increase in response on Day 4 of culture.
• The authors' conclusion: The authors concluded that chrysotile asbestos can significantly alter the laboratory mitogen responsiveness of human peripheral blood mononuclear cells.
• Limitations the authors state:
  • The authors stated that whether these laboratory observations contribute to human disease can only be hypothesized at this time.

Topics

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

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

Related studies

• In vitro depression of human lymphocyte mitogen response (phytohaemagglutinin) by asbestos fibres — R.G. Barbers, W.W. Shih, et al. (1982)
• Heterogeneity in immunologic functions of rat alveolar macrophages--their accessory cell function and IL-1 production — Y. Oghiso (1987)
• A novel human 3D lung microtissue model for nanoparticle-induced cell-matrix alterations — P.K. Kabadi, A.L. Rodd, et al. (2019)
• Polyclonal human T-cell activation by silicate in vitro — A. Ueki, M. Yamaguchi, et al. (1994)
• Activation of human CD4+CD45RA+ T cells by chrysotile asbestos in vitro — K. Kinugawa, A. Ueki, et al. (1992)
• Proliferation stimulating effects of chrysotile and crocidolite asbestos fibres on B lymphocyte cell lines — A. Ueki, T. Oka, et al. (1984)

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