Murine experimental leprosy: evaluation of immune response by analysis of peritoneal lavage cells and footpad histopathology

This study evaluated the immune response of nude and BALB/c mice inoculated in the footpads (FP) with Mycobacterium leprae after 3, 5 and 8 months. At each timepoint peritoneal cells, peripheral blood, FP and popliteal lymph nodes (PLN) were collected. Peritoneal cell cultures were performed to measure the H2O2, O2−, NO, IL­2, IL­4, IL­10, IL­12, IFN­Î³ and TNF levels. Serum levels of anti­PGL­I antibodies were also quantified. The results showed that the infection was progressive in nude mice with bacterial multiplication, development of macroscopic lesions in the FP and presence of bacilli in the PLN at 8 months. In BALB/c mice, the infection reached a plateau of bacillary multiplication at 5 months and regressed at 8 months. Histopathological analysis of FP revealed a mononuclear inflammatory infiltrate with a large number of neutrophils at 5 months, with a higher number in nude mice. At 8 months, the number of neutrophils decreased and the infiltrate was predominantly mononuclear in both mouse strains. There was no H2O2, O2−, IL­2, IL­4, IL­10 and IFN­Î³ production in the course of infection in nude mice; however, in BALB/c, O2− and IL­12 production was higher at 5 months and NO, IFN­Î³ and TNF production was higher at 8 months when there was a decrease in the number of bacilli. The level of anti­PGL­I antibodies was higher in BALB/c mice. Thus, nude and BALB/c mice can be used as experimental models for the study of various aspects of leprosy(AU).

Study of murine experimental Jorge Lobo's disease by analysis of peritoneal lavage cells and footpad histopathology: early versus chronic lesions

The murine model of Jorge Lobo's disease is characterized by histological alterations similar to those seen in human disease, including a large number of viable fungi. This study evaluated the immune response of mice with early and late macroscopic lesions (5 and 13 months post-inoculation [p.i.], respectively) by the analysis of peritoneal lavage cells and footpad (FP) histology. The FP of mice were inoculated with 1 × 106 fungi (viability index of 41%). At 5 and 13 months p.i., the granuloma mainly consisted of macrophages and multinucleated giant cells, but a larger number of neutrophils was observed at 5 months and lymphocytes at 13 months. The number of fungi in the FP and fungal viability were 1.8 ± 1.1 × 106 fungi/ml and 38.5% at 5 months p.i. and 30.8 ± 11.7 × 106 fungi/ml and 9% at 13 months (P < .05). Higher production of H2O2, O2−, IL-10, and TNF-α were observed at 13 months (P < .05), but there was no significant difference in the production of NO, IL-2, IL-4, IL-12 and IFN-γ. The results showed significant differences between early and late lesions and support the use of BALB/c mice for evaluation of the different phases of infection