[Activity of lysosomal hydrolases and renewal of proteins in the rat liver, spleen, and thymus during antigenic stimulation and protein deficiency].

Activity of cathepsins B and C was increased 1.8-2-fold in spleen simultaneously with a decrease 3.8-fold in the rate of protein renewal in the tissue lysosomal fraction within 4 days after antigen stimulation of rats, maintained within 45 days on a diet containing 5% of protein. Activation of these thiol-dependent proteinases appears to occur in response to development of immunodepressive conditions and may be related to alterations in the rate of their biosynthesis.