Characteristics of peritoneal macrophages induced by asbestos injection

Our plain-English summary of Characteristics of peritoneal macrophages induced by asbestos injection, by K. Donaldson, J.M. Davis, K. James (Environmental Research, 1982).

The study

• Authors: K. Donaldson, J.M. Davis, K. James
• Journal: Environmental Research
• Published: 1982;29(2):414-24
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The effect of single intraperitoneal injections of UICC crocidolite, UICC chrysotile, and a latex control particulate on the induced murine peritoneal macrophage population was measured. Spreading, Fc receptor avidity, and phagocytosis were measured 3, 18, and 70 days after injection. When activation of the induced macrophage populations was found at all three times with asbestos, but not with latex, experiments were undertaken to determine whether the asbestos-activated macrophages had attained the full tumoricidally activated state. An in vitro assay measuring macrophage cytotoxicity to tumor cells revealed that the tumoricidal potential of asbestos-activated macrophages was low at 3 and 5 days and negligible by 35 days after injection. An in vivo assay measuring the effect of asbestos on tumor growth generally supported the contention that asbestos-activated macrophages were not tumoricidal, although one dose of UICC chrysotile did produce a small, significant reduction in growth of a concomitant tumor. It was concluded that a single intraperitoneal asbestos injection in mice induces activated macrophages which do not become fully tumoricidal.

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

In plain English

In this mouse experiment at the University of Edinburgh, male CBA/Ca mice received a single injection into the abdominal (peritoneal) cavity of UICC crocidolite, UICC chrysotile, latex particles, or salt solution. The authors studied the immune cells called macrophages collected from the abdomen. Three days after asbestos injection, cell numbers were about five times control. They were back to control at 18 days and about three times control by 70 days. At all three time points, macrophages from both asbestos types showed signs of activation (more spreading and more antibody-coated red-cell binding) compared with saline. In laboratory tests, asbestos-induced macrophages killed few tumor cells, and very few by 35 days. Some mice were given a fibrosarcoma by injecting tumor cells under the skin. Among the asbestos treatments, only 5 mg chrysotile given 3 days after 10^6 tumor cells caused a small but significant reduction in tumor size. With 5 x 10^2 tumor cells, the same treatment had no significant effect. The authors concluded that asbestos-activated macrophages did not reach the fully tumor-killing state. They noted that the single-injection peritoneal model might be unsuitable.

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: Animal experiment (mice), with laboratory (in vitro) and live-animal (in vivo) tests of macrophage function
• Who was studied: Male CBA/Ca mice aged 10 to 14 weeks at injection, in groups of three per treatment and time point (two experiments pooled). Groups of ten mice were used for each condition in the tumor-growth tests. Department of Surgery, University of Edinburgh.
• Exposure: Single intraperitoneal injection of 2.5 mg UICC crocidolite or 2.5 mg UICC chrysotile, compared with 1% latex and salt solution (Dulbecco A). In the tumor-growth tests, chrysotile was given at 2.5, 5 or 20 mg and crocidolite at 5 mg, before or after subcutaneous inoculation of CCH1 fibrosarcoma cells. Corynebacterium parvum was used as a positive control.
• Main results:
  • Asbestos-injected mice: abdominal cell counts were about five times control at Day 3, at control level at Day 18, and about three times control by Day 70.
  • Macrophages from crocidolite- and chrysotile-injected mice spread significantly more than saline-induced macrophages at all three time points.
  • Fc receptor avidity (binding of lightly antibody-coated sheep red cells) of asbestos-induced macrophages was significantly greater than that of latex- or saline-induced macrophages. Latex also gave a significant increase at 3 days.
  • At 3 days, only crocidolite-induced macrophages had a significantly smaller proportion able to take up latex than saline-induced macrophages (P less than 0.05). At later time points all groups were about 95%.
  • Tumor-cell killing in the laboratory: asbestos-induced macrophages had mean toxicities of 10 to 15% at 3 days. At 5 days the mean was 20% for chrysotile and 5% for crocidolite.
  • By 35 days, macrophages induced by either asbestos type had very low toxicity to tumor cells.
  • Positive-control macrophages induced by C. parvum for 5 days had mean toxicity of 27.4% at a 5:1 ratio and 54.0% at a 10:1 ratio.
  • Mice with subcutaneously inoculated fibrosarcoma: among the asbestos regimens, only chrysotile given 3 days after 10^6 tumor cells produced a small but significant reduction in tumor size. For 5 mg, mean diameter was 13.8 versus 15.6 mm in controls (P less than 0.002), seen in two separate experiments. 2.5 mg and 20 mg chrysotile did not give significant reductions.
  • When the tumor-cell dose was lowered to 5 x 10^2 cells, the 5 mg chrysotile effect disappeared.
  • 5 mg chrysotile given 2 days before 5 x 10^2 tumor cells gave no significant reduction, although this regimen greatly increased the tumor-reducing effect of the positive control, C. parvum.
  • 5 mg crocidolite given 3 days after the tumor cells did not produce significantly smaller tumors.
• The authors' conclusion: The authors concluded that a single intraperitoneal asbestos injection in mice induced activated peritoneal macrophages in the short and long term, but these macrophages did not reach the fully activated, tumor-killing state.
• Limitations the authors state:
  • The single-injection peritoneal model might be unsuitable for studying asbestos activation of macrophages, because of the peritoneal site or because inhalation gives multiple doses.
  • Ia antigen expression, which relates to antigen-presenting function, was not measured.
  • The phagocytosis assay measured the proportion of cells able to take up latex, not the total amount taken up.
  • The tumor-growth results were conflicting, mostly negative, and difficult to interpret.

Topics

Medical terms in this study, explained in our Lexicon: Macrophage, UICC, Crocidolite, Chrysotile, Phagocytosis.

Related studies

• Asbestos-activated peritoneal macrophages release a factor(s) which inhibits lymphocyte mitogenesis — K. Donaldson, J.M. Davis, et al. (1984)
• Secretion of fibronectin by mineral dust-derived alveolar macrophages and activated peritoneal macrophages — R. Davies, G. Erdogdu (1989)
• Cytotoxic effect of asbestos on macrophages in different activation states — A. Wright, K. Donaldson, et al. (1983)
• An ultrastructural study of the effects of asbestos fibres on cultured peritoneal macrophages — N.F. Johnson, R. Davies (1981)
• Pleural macrophage recruitment and activation in asbestos-induced pleural injury — N. Choe, S. Tanaka, et al. (1997)
• Interactions of asbestos-activated macrophages with an experimental fibrosarcoma — K. Donaldson, J.M. Davis, et al. (1983)

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