Effect of fibrinogen degradation products on production of hepatocyte stimulating factor by a macrophage cell line (P388D1)

Abstract

Hepatocyte Stimulating Factor (HSF) is a monocyte/macrophage-derived regulatory protein which stimulates the hepatic synthesis of several plasma proteins. Plasminolytic peptides of fibrinogen or fibrin were tested for their ability to stimulate the secretion of HSF in an established macrophage cell line (P388D1). One of the peptides, fragment D, induced the production of HSF in the cells in a dose-dependent manner, while intact fibrinogen did not. A hierarchy of potency was established for the major plasminolytic fragments which is as follows: D greater than or equal to DD greater than X greater than or equal to E. Fragment D had no effect on production of interleukin-1, a potent monokine released by P388D1 cells. Taken together these results demonstrate that fragment D is a specific and potent inducer of HSF in P388D1 cells.