Protective role of unconjugated bilirubin on complement-mediated hepatocytolysis
| Autor: | Cecilia Lorena Basiglio, Marcelo G. Roma, Aldo D. Mottino, Héctor Fabián Pelusa, Sandra Mónica María Arriaga, Adriana M. Almará |
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| Rok vydání: | 2007 |
| Předmět: |
Male
Dose-Response Relationship Immunologic Biophysics Biochemistry Antibodies Immunoenzyme Techniques Classical complement pathway chemistry.chemical_compound Lactate dehydrogenase medicine Animals Rats Wistar Molecular Biology Cells Cultured chemistry.chemical_classification Complement Inactivator Proteins L-Lactate Dehydrogenase medicine.diagnostic_test biology Complement C1q Cell Membrane Bilirubin Human serum albumin Molecular biology Rats Enzyme medicine.anatomical_structure Microscopy Fluorescence chemistry Polyclonal antibodies Immunoassay Hepatocyte Hepatocytes biology.protein Antibody medicine.drug |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - General Subjects. 1770:1003-1010 |
| ISSN: | 0304-4165 |
| DOI: | 10.1016/j.bbagen.2007.03.005 |
| Popis: | Hyperbilirubinemia and complement-mediated immune attack on hepatocyte membrane are common features of certain hepatic diseases. To assess whether unconjugated bilirubin (UB) counteracts complement-mediated hepatocytolysis, we first generated a rabbit polyclonal antibody (Ab) against rat hepatocyte plasma membrane (RHPM). An assay performed with isolated rat hepatocytes in the presence of the polyclonal Ab and rat serum as complement donor demonstrated that UB inhibits cell lysis, as lactate dehydrogenase release into the medium was inhibited by the pigment in a dose-dependent manner. Immunofluorescence microscopy studies showed that UB significantly attenuates the binding of C3 to the hepatocyte–Ab complex. Further enzyme immunoassay studies showed that UB interferes the binding of C1q to purified anti-RHPM IgG, also in a dose-dependent manner. A dot-blot assay showed that [ 14 C]-UB binds to C1q and human serum albumin (HSA) to a similar extent. A differential spectrum analysis of UB in the presence of C1q further confirmed that the pigment interacts with this protein. In conclusion, we demonstrated an inhibitory action of UB on complement-mediated Ab-induced hepatocytolysis, this action being evidenced at pathophysiological pigment concentrations (171 μM and higher). A direct binding of the pigment to C1q is likely involved. |
| Databáze: | OpenAIRE |
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