Herbert L. Eckert

Depression of viral interferon induction in cell monolayers by asbestos fibers

Abstract Studies on the induction of interferon by influenza virus revealed that this adaptive cellular response was depressed, completely or partially, in either amosite, crocidolite, anthophyllite, Canadian or Rhodesian chrysotile-treated monkey kidney (LLC-MK 2 ) cell monolayers. Asbestos fiber concentrations of 1 mg/1.0 × 10 7 cells, which minimally affected cell viability, depressed interferon production by almost 90%. Increases in the virus-cell multiplicity of infection did not significantly increase interferon yields in asbestos fiber-treated cells. Chrysotile B fibers of lengths ranging from 10 to 5 μm were more effective in reducing interferon yields than those ranging from 75 to 625 μm. Maximal depression of interferon production was dependent on prior treatment of cell monolayers with asbestos fibers before the addition of viral inducer. The processes of virus integration (attachment and penetration) into and virus multiplication in cells were unaffected by the presence of asbestos fibers, however, a slightly higher level of virus replication was noted in asbestos fiber-treated cells. When cells were primed with interferon, the presence of asbestos fibers did not interfere with the ability of the primer to enhance interferon production. Neither interferon antagonists, interference with virus-cell interactions, nor adsorption by asbestos fibers accounted for the depression of interferon yields. These findings suggest that asbestos fibers act on cell membranes in a manner, as yet undetermined, to interpose in the viral inductive process of interferon synthesis.

Interferon assessment by the immunofluorescent, immunoperoxidase, and hemadsorption cell-counting techniques

SummaryThe immunofluorescent, immunoperoxidase, and hemadsorption cell-counting techniques were quantitatively evaluated for assessing interferon activity. The three assays exhibited parallel dose-responses and were comparable in sensitivity, precision, and reproducibility.