Opposite effects of M-leprae or M-bovis BCG delipidation on cellular accumulation into mouse pleural cavity. Distinct accomplishment of mycobacteriallipids in vivo

Objectives and Design: The effect of mycobacterial lipids on the onset of t he early acute inflammatory response in BALB/c mice pleurisy was investigat ed. Materials and Methods: Intact Mycobacterium leprae and Mycobacterium bovis BCG (BCG), their lipids, and delipidated mycobacteria were used to evaluate total leukocytes and cell types migrated to the pleural cavity (8 animals/ experimental group). Results: BCG Moreau (x 10(-6)/cavity), delipidated BCG and its lipids gradu ally recruited cells leading to arrival, respectively, of neutrophils (7.8 +/- 1.9, 4.7 +/- 0.9, 1.8 +/- 0.25) followed by mononuclear cells (4.8 +/- 0.8, 3.7 +/- 0.7, 2.45 +/- 0.22) and eosinophils (0.39 +/- 0.08, 0.32 +/- 0 .11, 0.41 +/- 0.65). BCG delipidation decreased the number of migrated tota l leukocytes (ANOVA, and Newman-Keuls-Student-test), whereas M. leprae deli pidation accumulated neutrophils (0.85 +/- 0.01) and eosinophils (1.65 +/- 0.18). Conclusions: Intact M. leprae and its lipids did not incite any cell recrui tment. Apolar external cell wall lipids from M leprae and BCG induce differ ent cellular responses. They seem to have a crucial importance at the first contact of mycobacteria with the host cell, modulating the influx of neutr ophils/macrophages in the early (4/24 h) onset of the inflammatory reaction .