Manifestations of cellular immunity in the rat after prolonged asbestos inhalation. II. Alveolar macrophage-induced splenic lymphocyte proliferation

Our plain-English summary of Manifestations of cellular immunity in the rat after prolonged asbestos inhalation. II. Alveolar macrophage-induced splenic lymphocyte proliferation, by K. Miller, E. Kagan (Environmental Research, 1981).

The study

• Authors: K. Miller, E. Kagan
• Journal: Environmental Research
• Published: 1981;26(1):182-94
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The present study has shown that alveolar macrophages from asbestos-exposed rats (dusted macrophages) can induce the proliferation of autologous splenic lymphocytes (dusted lymphocytes) as well as the proliferation of syngeneic lymphocytes from control nonexposed rats (control lymphocytes). Significant lymphoproliferation did not occur when alveolar macrophages from control rats (control macrophages) were cocultured with control or dusted splenic lymphocytes for similar periods of time (72 or 96 hr). The activation of control lymphocytes by dusted macrophages was similar, in some respects, to the lymphoproliferative response evoked by sodium periodate-treated control macrophages, since both these reactions peaked at 72 hr and were abolished by treatment of the macrophages with the reducing agent, L-cysteine. This periodate-like response produced by dusted macrophages appears to result from aldehyde-like modifications on the macrophage cell membrane. L-Cysteine treatment did not, however, affect the blastogenic response induced by dusted macrophages on dusted lymphocytes, which peaked at 96 hr. Since the in vitro addition of crocidolite to cell cultures did not trigger lymphoproliferation, these collective findings suggest the expression of asbestos-related antigen-like determinants on the surface of dusted macrophages. We conclude that the proliferative reactions induced in splenic lymphocytes by dusted macrophages were a consequence of two different phenomena: a periodate-like effect (noted in control lymphocytes) and an effect produced by a putative asbestos-related, macrophage-associated antigen (observed in dusted lymphocytes).

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

In plain English

This was an animal experiment. The authors exposed adult male inbred BD-IX rats to UICC crocidolite asbestos dust (1350 fibers/ml; 10.3 mg/m3) for 8 hours a day, 5 days a week. After 6 months, the exposed ("dusted") rats and unexposed control rats were killed. Lung immune cells called alveolar macrophages and spleen lymphocytes were then grown together in the laboratory, and lymphocyte multiplication was measured. Macrophages from control rats did not cause significant lymphocyte multiplication. Macrophages from dusted rats did, with lymphocytes from both dusted and control rats. Treating dusted macrophages with L-cysteine significantly reduced their effect on control lymphocytes but made no significant difference for dusted lymphocytes. Crocidolite added directly to the cultures did not trigger multiplication. The authors concluded that the responses came from two different effects. One was a periodate-like effect, resembling macrophages treated with sodium periodate, which they linked to aldehyde-like changes on the macrophage surface. The other was an effect of a putative asbestos-related antigen carried by the macrophages. The article does not report how many rats were used.

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: rats exposed to asbestos by inhalation, followed by laboratory (in vitro) coculture of their alveolar macrophages and spleen lymphocytes
• Who was studied: Adult male inbred BD-IX rats, placed in inhalation chambers at 3 to 4 months of age, plus age- and weight-matched unexposed control rats; killed after 6 months; number of animals not stated; work done largely at the National Centre for Occupational Health, Johannesburg, South Africa
• Exposure: UICC crocidolite asbestos by inhalation, 1350 fibers/ml (gravimetric concentration 10.3 mg/m3), 8 hr a day, 5 days a week, for 6 months. In separate culture experiments crocidolite was also added directly to cells.
• Main results:
  • Macrophages from control rats cultured with lymphocytes from control rats caused no significant lymphocyte proliferation at 72 or 96 hr. The same was true for control macrophages cultured with dusted lymphocytes.
  • Dusted macrophages cultured with dusted lymphocytes gave 9873 plus or minus 1790 dpm at 72 hr and 11,838 plus or minus 2515 dpm at 96 hr. This was significantly greater (P < 0.001) than control macrophages with control lymphocytes (1496 plus or minus 298 dpm and 1851 plus or minus 327 dpm).
  • Dusted macrophages cultured with control lymphocytes gave a response that peaked at 72 hr: 15,440 plus or minus 4368 dpm, compared with 11,879 plus or minus 2794 dpm at 96 hr (t = 3.85; P < 0.005).
  • Optimal proliferation of dusted lymphocytes occurred at macrophage-to-lymphocyte ratios of about 1:10 to 1:5.
  • Dusted macrophages cultured alone showed low uptake: 548 plus or minus 314 dpm at 72 hr and 575 plus or minus 428 dpm at 96 hr. The authors took this to show the uptake in cocultures was lymphocyte proliferation, not macrophage replication.
  • Control macrophages treated with sodium periodate induced proliferation of both dusted and control lymphocytes, maximal at 72 hr. L-cysteine treatment of these macrophages markedly decreased the response, especially at 72 hr (P < 0.001).
  • L-cysteine-treated dusted macrophages with control lymphocytes gave 3168 plus or minus 279 dpm at 72 hr and 3447 plus or minus 1108 dpm at 96 hr. These responses were significantly reduced (P < 0.001) compared with untreated dusted macrophages.
  • For dusted lymphocytes, there was no significant difference (P > 0.05) between untreated and L-cysteine-treated dusted macrophages at 72 or 96 hr.
  • Crocidolite added directly to cultures caused no significant thymidine uptake. This was tested on control macrophages alone, control lymphocytes alone, and control macrophages with control or dusted lymphocytes.
• The authors' conclusion: The authors concluded that the lymphocyte proliferation induced by dusted macrophages resulted from two different phenomena. One was a periodate-like effect (seen in control lymphocytes). The other was an effect of a putative asbestos-related, macrophage-associated antigen (seen in dusted lymphocytes).
• Limitations the authors state:
  • The authors state that the role of Ir gene products in the lymphocyte proliferation induced by dusted macrophages was not defined in this study and needs further work.

Topics

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

Medical terms in this study, explained in our Lexicon: Alveolar Macrophage, Macrophage, Crocidolite.

Related studies

• Asbestos inhalation and the induction of splenic lymphocytic proliferation in the rat — E. Kagan, K. Miller (1981)
• Alveolar macrophage stimulation of lung fibroblast growth in asbestos-induced pulmonary fibrosis — I. Lemaire, H. Beaudoin, et al. (1986)
• Asbestos-induced alveolar injury. Evidence for macrophage-derived PDGF as a mediator of the fibrogenic response — J.C. Bonner, A.R. Brody (1991)
• Effects of asbestos fibers on alveolar macrophage-mediated lymphocyte cytostasis — B.E. Bozelka, P. Sestini, et al. (1986)
• Lymphocyte-macrophage alveolitis in nonsmoking individuals occupationally exposed to asbestos — W.N. Rom, W.D. Travis (1992)
• Immune adherence reactivity of rat alveolar macrophages following inhalation of crocidolite asbestos — K. Miller, E. Kagan (1977)

Browse more research in Environmental Research, or return to medical research.