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Stimulated Platelets Release Factor(s) Affecting the In Vitro Response of Human Polymorphonuclear Cells
Author(s) -
Del Principe Domenico,
Menichelli Adriana,
Di Giulio Stefano,
De Matteis Walter,
Giordani Massimo,
Pentassuglio Anna Maria,
FinazziAgro Alessandro
Publication year - 1990
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.48.1.7
Subject(s) - platelet , myeloperoxidase , zymosan , thrombin , lactate dehydrogenase , microbiology and biotechnology , biology , biochemistry , phorbol , in vitro , immunology , protein kinase c , inflammation , enzyme
The metabolic and functional responses of human polymorphonuclear cells (PMNs) to thrombin‐activated platelet supernatants were studied. The incubation of PMNs with supernatants from stimulated platelets (SPS) caused a 50% decrease in both killing of Staphylococcus aureus and luminol‐enhanced chemiluminescence (CL) by PMNs stimulated by opsonized‐zymosan (OZ), Concanavalin A (Con A), or calcium ionophore A23187. The levels of PMN intracellular fluorescence measured by flow cytometry, using the fluorochrome dichlorofluorescin diacetate (DCF‐DA), were considerably less in the presence of SPS than in resting platelet supernatants (RPS). No influence of platelet supernatant on O 2 consumption and O 2 ‐ generation by OZ‐activated PMNs was observed. The incubation of PMNs with SPS caused a significant increase in the rate of chemotaxis and aggregation elicited by Con A, OZ, and phorbol myristate acetate (PMA). The supernatant from resting platelets did not show any of the above‐reported effects. Platelets previously degranulated by thrombin were unable to inhibit CL when activated with agonists. Studies on the differential release of the granules by platelets showed that the CL‐quenching activity paralleled the discharge of lysosomal content The release of myeloperoxidase (MPO) from PMNs elicited by OZ was reduced in the presence of SPS. The platelet supernatant did not affect the MPO activity if PMNs were lysed with Triton X‐100. The leakage of lactate dehydrogenase (LDH) from platelets was less than 3%, and no catalase or superoxide dismutase was released. This activity withstood lyophilization, but was destroyed by 10 min heating at 100°C or by treatment with proteolytic enzymes.