ABSTRACT
This chapter reviews the state of knowledge based on the circumstantial evidence that tends to support this concept. Among the many cell types that produce fibronectin and are affected by this multifunctional protein, it includes the polymorphonuclear neutrophil (PMN). Protein synthesis and secretion by PMN is an area of study which remains relatively unexplored. In the presence of fibronectin, efficient phagocytosis took place. The role of fibronectin in promoting the adherence of PMN to substrata has been studied by several investigators. Plasma fibronectin inhibited the adherence of PMN to glass and protein-coated surfaces. In view of the similarities noted between the monocyte and PMN fibronectin receptors, it was suggested that fibronectin might exert its opsonic activity on PMN through a closely related mechanism. The possibility exists that there is actually a series of fibronectin molecules produced by differences in splicing by various cell types, or even within one cell.
