Activation of the alternative complement pathway and generation of chemotactic factors by asbestos

Our plain-English summary of Activation of the alternative complement pathway and generation of chemotactic factors by asbestos, by M.R. Wilson, H.R. Gaumer, J.E. Salvaggio (The Journal of Allergy and Clinical Immunology, 1977).

The study

• Authors: M.R. Wilson, H.R. Gaumer, J.E. Salvaggio
• Journal: The Journal of Allergy and Clinical Immunology
• Published: 1977;60(4):218-22
• Cited by: 70 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Five types of asbestos plus silica and glass wool fibers were tested for their ability to activate the alternative complement pathway and to generate chemotactic factor activity from fresh normal human serum (NHS). Two assays were used to detect alternative pathway activation by the fibers. The first method was a hemolytic assay that utilized glutathione-sensitized human erythrocytes (GSHE) to detect the C5b-C9 complexes generated by activation of fresh NHS with the various fibers. The second method was an immunoelectrophoretic assay to detect split products of activation of factor B after the fibers were incubated with NHS. Both assays were performed under conditions that have been shown to block the initial steps of classical pathway activation but permit activation of the alternative complement pathway. All five asbestos fibers tested, amosite, anthophyllite, crocidolite, and chrysotiles A and B activated the alternative pathway when tested by both methods. In addition, it was demonstrated that chemotactic factor activity was generated when asbestos fibers were incubated with fresh NHS. In contrast, silica and glass wool fibers did not activate the alternative complement pathway and did not generate chemotactic factor activity. These observations suggest that the complement system may mediate the initial inflammatory response observed upon exposure to certain types of asbestos fibers.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This was a laboratory (test-tube) study, not a study of people exposed to asbestos. The authors mixed five standard reference asbestos samples (amosite, anthophyllite, crocidolite, Rhodesian chrysotile A and Canadian chrysotile B) with fresh serum from healthy donors. Crystalline silica and glass wool were tested for comparison. They tested whether the fibers switched on the "alternative pathway" of complement, a set of blood proteins the authors describe as a major mediator of tissue injury. They used two methods. All five asbestos types activated the pathway by both methods, with red-cell lysis of 34.2% to 46.6% compared with an inulin standard. Silica and glass wool did not. On their own, chrysotile A and B destroyed more than 95% of the test red cells. Acid treatment removed that effect but did not change complement activation. Amosite, anthophyllite, crocidolite and chrysotile B also generated factors that attracted white blood cells (net migration 17.7 mm to 23.0 mm); silica did not. The authors suggested that activation of this pathway may be responsible for tissue injury after asbestos exposure.

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 using human serum and blood cells
• Who was studied: Fresh normal human serum from healthy donors (number of donors not stated), with human red blood cells and white blood cells used as test cells; Tulane University Medical Center, New Orleans
• Exposure: Five UICC standard reference asbestos samples: amosite, anthophyllite, crocidolite, Rhodesian chrysotile A and Canadian chrysotile B. Crystalline silica and Pyrex glass wool served as control fibers.
• Main results:
  • Without serum, chrysotile A and chrysotile B directly destroyed more than 95% of the test red cells; amosite, anthophyllite and crocidolite did not
  • Acid leaching of chrysotile A and chrysotile B abolished this direct cell-destroying effect
  • All five asbestos fiber types activated the alternative complement pathway by both assay methods
  • Complement-dependent red-cell lysis by the asbestos fibers ranged from 34.2% to 46.6% relative to an inulin-activated standard. Table II values (mean and standard deviation of 8 experiments): amosite 44.1 plus or minus 1.7; anthophyllite 46.6 plus or minus 0.6; crocidolite 44.2 plus or minus 3.0; chrysotile A 34.3 plus or minus 13.2; chrysotile B 34.2 plus or minus 9.9. More than 5% lysis counted as activation.
  • Acid leaching of the fibers did not affect the complement-dependent lysis they produced
  • Silica and glass wool did not activate the alternative pathway by either method. In Table II, silica produced 2.0 plus or minus 2.1% lysis and glass wool less than 1.0%.
  • Amosite, anthophyllite and crocidolite tested at several doses showed about the same degree of complement activation at each dose
  • Amosite, anthophyllite, crocidolite and chrysotile B generated chemotactic (white-cell-attracting) activity in fresh serum. Net migration ranged from 17.7 mm for crocidolite to 23.0 mm for chrysotile B, compared with 25.1 mm for the inulin control.
  • Silica did not generate chemotactic activity (net migration 3.4 mm in Table III), and asbestos fibers alone, without serum, did not attract white blood cells
• The authors' conclusion: The authors suggested that activation of the alternative complement pathway may be responsible for tissue injury after asbestos exposure, and that the complement system may mediate the initial inflammatory response to certain types of asbestos fibers.

Topics

Medical terms in this study, explained in our Lexicon: Glutathione (GSH), Amosite, Anthophyllite, Crocidolite, Chrysotile.

Related studies

• Impaired chemotactic responses of bronchoalveolar leukocytes in experimental pneumoconiosis — K. Donaldson, G.M. Brown, et al. (1990)
• In vitro cleavage by asbestos fibers of the fifth component of human complement through free-radical generation and kallikrein activation — M. Governa, M. Amati, et al. (2000)
• Wollastonite fibers in vitro generate reactive oxygen species able to lyse erythrocytes and activate the complement alternate pathway — M. Governa, L. Camilucci, et al. (1998)
• Time course of chemotactic factor generation and the corresponding macrophage response to asbestos inhalation — D.B. Warheit, L.H. Hill, et al. (1986)
• Chemotactic factor generation by asbestos. Fibre type differences and the effects of leaching — E. Yano, A. Takeuch, et al. (1984)
• Pulmonary macrophages are attracted to inhaled particles through complement activation — D.B. Warheit, L.H. Overby, et al. (1988)

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