Eosinophil leukocyte degranulation in response to serum-opsonized beads: C5a and platelet-activating factor enhance ECP release, with roles for protein kinases A and C
| Autor: | Arne Egesten, Johan Malm |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Time Factors
education Immunology Complement C5a Enzyme-Linked Immunosorbent Assay Naphthalenes Pharmacology Biology Cell Degranulation chemistry.chemical_compound Ribonucleases fluids and secretions Leukocyte degranulation Humans Immunology and Allergy Eosinophil degranulation Enzyme Inhibitors Platelet Activating Factor Protein kinase A Protein Kinase C Protein kinase C Eosinophil cationic protein Platelet-activating factor Eosinophil Granule Proteins Degranulation Blood Proteins Staurosporine Cyclic AMP-Dependent Protein Kinases Molecular biology Eosinophils chemistry |
| Zdroj: | Allergy. 53:1066-1073 |
| ISSN: | 1398-9995 0105-4538 |
| DOI: | 10.1111/j.1398-9995.1998.tb03816.x |
| Popis: | BACKGROUND: Eosinophils have a typical content of granule-bound, cytotoxic, cationic proteins which may, when released to the external milieu, play roles in diseases such as asthma and parasitic infestation. Therefore, we have investigated possible mechanisms by which their release is regulated in eosinophils. METHODS: The enzyme-linked immunosorbent assay (ELISA) was used to detect released eosinophil cationic protein (ECP). Release of ECP was induced by serum-opsonized, nonphagocytosable Sephadex beads (SOS). RESULTS: The complement fragment C5a and platelet-activating factor (PAF) were found to enhance ECP release in response to SOS in a dose-dependent fashion, and, contrary to previous reports, they were not found to act as secretagogues themselves on eosinophils in suspension. The role of protein kinase C (PKC) in eosinophil degranulation has been controversial. We found that ECP release induced by SOS was inhibited by the PKC inhibitors staurosporine and calphostin C. Activation of protein kinase A (PKA), by raising cAMP, also inhibited ECP release. Furthermore, pertussis toxin decreased ECP release on opsonized beads, indicating the involvement of pertussis-toxin-sensitive G proteins. CONCLUSIONS: C5a, and PAF enhance granule release, rather than acting as secretagogues themselves. PKC and PKA have opposing roles in the regulation of ECP release in response to SOS. |
| Databáze: | OpenAIRE |
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