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A novel biological effect of platelet factor 4 (PF4): enhancement of LPS‐induced tissue factor activity in monocytes
Author(s) -
Engstad Charlotte Sissener,
Lia Karin,
Rekdal Øystein,
Olsen Jan Ole,
Østeoid Bjarne
Publication year - 1995
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.58.5.575
Subject(s) - platelet factor 4 , monocyte , platelet , lipopolysaccharide , tissue factor , platelet activation , tumor necrosis factor alpha , whole blood , platelet lysate , granulocyte , pharmacology , secretion , biology , immunology , chemistry , medicine , endocrinology , coagulation
In a previous study we have shown that granulocytes enhance lipopolysaccharide (LPS)‐induced tissue factor (TF) activity in monocytes in a platelet‐dependent reaction. The present investigation was undertaken to examine the role of a platelet activation product, platelet factor 4 (PF4), in LPS‐induced TF activity in monocytes. Platelet lysate supernatant, purified PF4, and the COOH‐terminal tridecapeptide of PF4, termed PF4(58–70), enhanced LPS‐induced TF activity in monocytes of whole blood dose dependently. A monoclonal antibody against P‐selectin eliminated the enhancing effect of PF4(58–70) on LPS‐induced TF activity in monocytes, and PF4(58–70) was shown to act synergistically with tumor necrosis factor α (TNF‐α). However, PF4(58–70) did not enhance TNF‐α secretion in LPS‐stimulated whole blood. The major effect of PF4(58–70) was granulocyte dependent. Our results suggest that PF4 might play an important role in LPS‐stimulated monocyte TF activity of whole blood.