Effect of a homologous beta-interferon preparation on degradation of Escherichia coli and on lysosomal enzyme activities in mouse peritoneal macrophages.

The degradation of 32P-labelled E. coli and the activity of three lysosomal enzymes, acid phosphatase, cathepsin D and beta-glucuronidase, in mouse peritoneal macrophages (MPM) were tested after cultivation of the cells for 24 or 48 hours with 10(1) - 10(4.7) U per ml of a homologous beta-interferon preparation (IFN-beta). Low to moderate concentrations of IFN-beta did not influence bacterial degradation in MPM. However, a reduction in bacterial degradation by 20 per cent or more was seen when the MPM were pre-treated with 10(4.7) U per ml for 24 hours or 10(3) U per ml of IFN-beta for 48 hours. Cultivation of the MPM with 10(2) U per ml of IFN-beta suppressed the activities of the lysosomal enzymes, provided that the cells were treated for 48 hours. The beta--glucuronidase activity was significantly reduced also after 24 hours. Increased release of beta-glucuronidase from MPM to the medium during cultivation with 10(2) U per ml of IFN-beta was also observed. Specific anti-IFN-beta globulin abolished the suppression by IFN-beta on the lysosomal enzyme activities. A human IFN-alpha preparation did not influence bacterial degradation or lysosomal enzyme activities in MPM.