The role of plasma factors in the adherence of leucocytes to vascular endothelial cells.

Studies have been undertaken to search for humoral factors present in the plasma from animals undergoing inflammation which may promote specific cell types to adhere to vascular endothelium. We have tested both plasma from animals with "acute" pleural inflammation and animals with "chronic" carrageenan air pouch granulomata for the presence of leucocyte pro-adhesive activity. Plasma from animals with carrageenan pleurisy had augmented polymorph adhesive activity. This activity was absent in the plasma from animals with air pouch granulomata. No such pro-adhesive activity for mononuclear cells was detected in this plasma. We conclude that the initial influx of polymorphs during the early stages of inflammation may in part be due to systemic pro-adhesive factors. It is proposed that these factors in combination with chemotaxins released at the lesion site are responsible for the early dominance of polymorphs.