Phagocytic and bactericidal activities of macrophages from Mycobacterium leprae-infected normal and immunosuppressed mice.

Phagocytic and bactericidal activities were studied in Mycobacterium leprae-infected normal (NI) and thymectomized/irradiated (TRI) mice at different time periods. No significant differences were seen in the phagocytic activity for Staphylococcus aureus at 3, 6, and 9 months in the normal infected (NI) and normal control (NC) mice. A slight but significant decrease in the phagocytosis of S. aureus was seen in the TRI as compared to the NI group at 3 months which recovered at 6 months. Phagocytosis of sheep erythrocytes was depressed in the TRI as compared to the NI group at 6 months only. No significant differences in the phagocytosis of latex particles were seen in any of the groups at any time of infection. Bactericidal activity was significantly reduced in the NI group as compared to the NC group and, similarly, in the TRI group as compared to the TRC group at all periods of infection. The M. leprae-infected T/R 900 group (TRI) showed more decrease in bactericidal activity when compared to the normal infected (NI) group.