[The effect of actinomycin D on lysosomal proteinase activity in murine macrophages and spleen during immune...

Actinomycin D inhibited activation of lysosomal cathepsins A, B, C, D, H and L in peritoneal macrophages, caused by T-dependent antigen (sheep erythrocytes), of mice CBA X C57BL/6 strain. At the same time, the antibiotic stimulated activity of cathepsins A, C, D and H but decreased content of antibody-producing cells in spleen tissue. Inhibition of lysosomal proteinases in macrophages may be responsible for immunodepressive effect of actinomycin D.