An in vitro model system to evaluate pulmonary macrophage, endothelial cell, and neutrophil interactions.

Pasteurella haemolytica, the cause of fibrinous pleuropneumonia in cattle, produces extensive microvascular endothelial cell (EC) damage. We have developed an in vitro model system to study the inflammatory process of this disease involving the interaction of pulmonary alveolar macrophages (AM), neutrophils (PMN), and EC. Bovine EC are grown to confluency in 24 well tissue culture plates. To mimic the vascular component, 10(6) PMN are later added to the EC monolayers. Bovine AM are plated onto millicell inserts and placed into the wells containing EC and PMN. The millicell insert serves as a semi-permeable barrier between AM and EC, allowing the exchange of only diffusible material. Preliminary work demonstrates that P. haemolytica stimulated AM resulted in EC damage presumably due to both soluble lipopolysaccharide and AM secreted products.