[Role of age-related serum factors in the mechanism of interferon production].

The activity (free and total) of cathepsin D and acid phosphatase was studied in cells of peritoneal exudate of mice of different ages in the process of interferon production in the presence of sera from newborn and adult animals. Cathepsin D release in newborn mice upon interferon induction is actively stimulated by serum factors of newborn animals altering lysosome permeability selectively for this enzyme alone. Another lysosomal enzyme, acid phosphatase, was more strongly bound to the structures and showed no such features. With an increased age of the donor the amount of stimulating factors in the serum decreases and that of inhibiting factors increases. Inhibition of cathepsin release from lysosomes by the serum factor of adult animals protects the synthesized interferon molecules from degradation and facilitates intensive interferon production in adult mice. A higher susceptibility of children to virus infections and inefficiency of the earliest defence system, interferon, may be due to degradation of newly synthesized interferon molecules by lysosomal cathepsin D.