Studies on the ability of inflammatory exudate obtained from acute and chronic phases of the inflammatory process to promote leukocyte locomotion in vitro.

Using a modified Boyden chamber system, inflammatory exudates taken from the acute carrageenan pleural model and the chronic carrageenan air-pouch model were tested for their ability to promote leukocyte locomotion in vitro. Both exudates were able to induce polymorphonuclear leukocyte (PMN) and mononuclear leukocyte (MN) migration, suggesting that cell-specific chemoattractants are not responsible for the progression of the inflammatory process from the acute to the chronic phase. Checkerboard assay were used to establish whether the observed migration was in response to chemotactic stimulation and/or chemokinetic stimulation. Both acute and chronic exudates were able to induce MN chemotaxis and chemokinesis. Acute exudate was able to induce PMN chemotaxis and chemokinesis. Acute exudate was able to induce PMN chemotaxis and chemokinesis, but chronic exudate was only able to induce PMN chemokinesis. This may partly explain the predominance of MNs in chronic inflammation. However, our present in vitro results have failed to demonstrate that cell-specific chemoattractants are responsible for the in vivo observation that migration of polymorphonuclear leukocytes precedes the migration of mononuclear cells.