Effect of coal rank on the interferon system.

Studies on the induction of interferon by influenza virus in monkey kidney (LLC-MK2) cell monolayers pretreated with coal dust revealed that the inhibitory activity of the mineral on this process was related to coal rank. Maximal inhibition of viral interferon induction was noted with high rank coal and the degression of this activity was related to coal's position in the carboniferous series; anthracite, bituminous, subbituminous, lignite, and peat. The cytocidal activity of each rank of coal, however, was comparable in relation to the corresponding quantities of coal dust that were tested indicating that findings related to interferon production are not explicable on the basis of remaining viable cells. Coal dust, irrespective of rank, also did not affect the ability of exogenous interferon to confer antiviral cellular protection. An inverse relationship mediated by coal of different rank occurred between influenza virus growth and interferon levels which suggested that increased virus growth reflected the ability of higher rank coal to affect adversely interferon production.