Acid phosphatase stimulation of the growth of Nocardia asteroides and its possible relationship to the modification of lysosomal enzymes in macrophages.

Lysosomal acid phosphatase levels are reduced in murine macrophages by virulent strains of Nocardia asteroides. At the same time, other lysosomal enzymes either remain unchanged or increase in activity, indicating that acid phosphatase is not lost because of degranulation or membrane leakage. This study shows that acid phosphatase was utilized as a sole carbon source by Nocardia asteroides and that acid phosphatase combined with glutamate as a carbon source enhanced nocardial growth. As a consequence, the inverse relationship that was observed between acid phosphatase activity and the bactericidal capacity of macrophages infected with N. asteroides appears to be due to the ability of N. asteroides to preferentially metabolize this lysosomal enzyme during growth within phagocytes.