Fink, Danielle2023-12-012023-12-012005-11http://hdl.handle.net/11603/30989Polymorphonuclear neutrophils (PMNs) of the innate immune system are responsible for ingestion and killing of invading microorganisms. However, microbial clearance by PMNs requires chemotaxis along a chemoattractant gradient from the vasculature to an infectious focus. Shown here, treatment of PMNs with fibrinogen enhances migration to the chemoattractant, formyl-methionyl-leucyl-phenylalanine (fMLF), increasing the number of migrating PMNs and migratory distance. Previous studies demonstrated that fibrinogen enhanced MU-stimulated production of another chemoattractant, interleukin-8 (IL-8). IL-8, released by migrating PMNs, could provide an additional chemoattractant for the further migration of additional PMNs, amplifying the inflammatory response. The cationic nature of IL-8 could facilitate its immobilization to the extracellular matrix into chemoattractant "trails." Using "underagarose" chemotaxis and amplified immunofluorescence staining, areas of extracellular IL-8 staining were identified; however, instead of specific deposition of IL-8, these areas appeared to result from nonspecific deposition of cellular debris since they contained other cellular components such as B-actin.54 pagesen-USText