Effects of in vitro asbestos exposure on natural killer and antibody-dependent cellular cytotoxicity

Our plain-English summary of Effects of in vitro asbestos exposure on natural killer and antibody-dependent cellular cytotoxicity, by R.G. Barbers, J. Oishi (Environmental Research, 1987).

The study

• Authors: R.G. Barbers, J. Oishi
• Journal: Environmental Research
• Published: 1987;43(1):217-26
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Human peripheral blood lymphocytes (PBL) were exposed in vitro to asbestos fibers. Antibody-dependent cellular cytotoxicity (ADCC) activity and natural killer (NK) activity were examined by a chromium-51 release assay. There was a statistically significant enhancement of ADCC and NK activity by chrysotile and crocidolite fibers when cultured together with PBL for a period of 42 hr in medium containing a concentration of at least 2.5% fetal calf serum (P less than 0.05). Isolation of large granular lymphocytes to measure NK activity, however, showed the opposite effect when exposed to asbestos fibers (P less than 0.05). Our results indicate that asbestos fibers can directly affect lymphoid cytotoxic responses in vitro and may provide clues to immunopathogenic mechanisms for the occurrence of neoplasms in vivo.

In plain English

This was a laboratory study. The authors exposed white blood cells from 15 healthy nonsmoking donors (3 men and 12 women, average age 33.4 years, with no known asbestos exposure) to asbestos fibers outside the body. They used standard reference crocidolite and Rhodesian chrysotile A fibers, with Pyrex glass wool as a control fiber. They then measured two kinds of tumor-cell killing: natural killer (NK) activity and antibody-dependent cellular cytotoxicity (ADCC). In medium with 15% fetal calf serum, chrysotile and crocidolite both increased NK and ADCC activity of the lymphocyte fraction after 42 hours compared with glass wool (P less than 0.05). Results in other serum conditions were mixed. In 2.5% fetal calf serum, the NK increase was significant only for crocidolite compared with medium controls, and no significant ADCC change was found. A purified subgroup called large granular lymphocytes showed significantly reduced NK activity after 42 hours with chrysotile. The authors concluded that lymphocyte cytotoxic responses were altered after this exposure in the laboratory. They said the reasons for the differing results were unclear.

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: Laboratory (in vitro) experiment on human blood cells
• Who was studied: Blood cells from 15 healthy nonsmoking donors (3 men, 12 women, average age 33.4 years) with no known asbestos exposure, studied at the UCLA School of Medicine
• Exposure: UICC standard reference crocidolite and Rhodesian chrysotile A fibers, with Pyrex glass wool as control fibers, sonicated to lengths of 10 to 50 micrometers. Cells were incubated with 50, 100 or 250 micrograms of fibers per million nonadherent cells for 18 or 42 hours.
• Main results:
  • In nonadherent lymphocytes incubated 42 hours in 15% fetal calf serum, chrysotile and crocidolite both enhanced NK activity; the difference from glass wool control fibers was significant (P less than 0.05)
  • In 2.5% fetal calf serum after 42 hours, NK activity rose compared with medium controls for crocidolite (P less than 0.01) but not significantly for chrysotile. Neither was significant compared with glass wool, which also showed enhanced activity.
  • In large granular lymphocytes exposed to chrysotile for 42 hours in 2.5% fetal calf serum (n = 4), NK activity was significantly reduced versus unexposed cells. Values with versus without fiber were 27.4 plus or minus 3.47 versus 35.6 plus or minus 3.68 at a 25:1 ratio (P less than 0.01), and 18.1 plus or minus 1.87 versus 23.5 plus or minus 3.19 at 10:1 (P less than 0.05). In the same table, nonadherent cells showed 24.5 versus 32.5 (P greater than 0.2) and 16.2 versus 19.2 (P greater than 0.5).
  • In 15% fetal calf serum after 42 hours, ADCC of nonadherent lymphocytes was significantly enhanced by crocidolite and chrysotile compared with glass wool, more so with chrysotile
  • In 2.5% fetal calf serum, no significant differences in ADCC were found after 18 or 42 hours with fibers compared with medium or glass wool controls
  • With human serum in the medium (cord blood serum and pooled human serum, n = 4), chrysotile was followed by lower NK and ADCC activity versus controls (0.51 plus or minus 0.19), but this was not statistically significant
• The authors' conclusion: The authors concluded that lymphocyte cytotoxic responses were altered after in vitro exposure to asbestos fibers, and that this system may give clues to immune events in asbestos-related cancer
• Limitations the authors state:
  • The reasons for the opposite effects in nonadherent lymphocytes and large granular lymphocytes were unclear
  • Effects of asbestos fibers on lung lymphocytes are unknown; the study used blood cells
  • Exposure periods shorter than 18 hours were technically difficult to perform
  • NK cell proliferation was not examined

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Chrysotile, Crocidolite, Neoplasm.

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