Effects of inhibitors of inflammatory mediators and cytokines on eosinophil and neutrophil accumulation induced by <i>Mycobacterium bovis bacillus Calmette-Guérin</i>in mouse pleurisy

In this work we characterize the Mycobacterium bovis bacillus Calmette-Guerin (BCG) -induced pleurisy and investigate the role of chemical mediators and cytokines in BCG-induced granulocyte accumulation at 24 h. Intrathoracic injection of BCG in C57B1/6 mice induces a biphasic inflammatory reaction with intense leukocyte accumulation at 24 h and 15 days. Neutrophils were observed in the pleural cavity at 4-24 h, mononuclear cells and eosinophils after 24 h. A new wave of mononuclear cells and neutrophils were observed after 15 days. Pretreatments with dexamethasone, BW 755C, BW A4C, WEB 2170, L-NAME, and monoclonal antibody (mAb) anti-interleukin-5 (IL-5; TRFK-5) had inhibited the eosinophil accumulation. On the other hand, only the pretreatments with dexamethasone, L-NAME, or mAb anti-tumor necrosis factor alpha (TNF-alpha; MP6-XT3) had inhibited the neutrophil influx. These results suggest the involvement of leukotrienes, platelet-activating factor, nitric oxide, and IL-5 in the eosinophil accumulation, and a role for nitric oxide and TNF-alpha in the neutrophil influx induced by BCG.