Reduction of pulmonary mast cells in areas of acute inflammation in calveswith Mannheimia (Pasteurella) haemolytica pneumonia

Mast cells in the left cranial pulmonary lobe of colostrum-deprived neonata l calves were quantified 2 and 6 h after intrabronchial inoculation with Ma nnheimia (Pasteurella) haemolytica Al. The mast cells were detected ii) imm unohistochemically with a mouse anti-human mast cell tryptase monoclonal an tibody, and (2) by metachromatic staining with low pH toluidine blue. A gre ater number of mast cells was demonstrated by the second method than by the first. At 6 h after inoculation, but not at 2 h, the number of mast cells was significantly reduced at the site of the main lesions. Treatment of cal ves with a sialyl Lewis mimetic (TBC 1269) did not appreciably affect the r esults at 6 h. (C) 2000 Harcourt Publishers Ltd.