Hypocomplementemia of Membranoproliferative Nephritis DEPENDENCE OF THE NEPHRITIC FACTOR REACTION ON PROPERDIN FACTOR B
| Autor: | Judith Forristal, Edward J. Ruley, Cynthia Andres, Neil C. Davis, Clark D. West |
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| Rok vydání: | 1973 |
| Předmět: |
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Cleavage (embryo) Complement factor B Cofactor Absorption chemistry.chemical_compound Immune system medicine Humans Immunoelectrophoresis Nephritis Properdin biology Zymosan Complement System Proteins Articles General Medicine Blood Protein Electrophoresis medicine.disease Molecular biology In vitro chemistry Immunology biology.protein Electrophoresis Polyacrylamide Gel |
| Zdroj: | Journal of Clinical Investigation. 52:896-904 |
| ISSN: | 0021-9738 |
| DOI: | 10.1172/jci107254 |
| Popis: | Membranoproliferative nephritis in children is frequently associated with a hypocomplementemia produced at least in part by C3 breakdown mediated by a circulating anticomplementary factor known as C3 nephritic factor (C3NeF). C3 breakdown by this factor in vitro requires the presence of a pseudoglobulin cofactor and magnesium. The present study provides evidence that properdin factor B (C3 proactivator) is activated in the nephritic factor reaction and is the direct mediator of C3 breakdown by C3NeF. Depletion of factor B from mixtures of normal human serum (NHS) and plasma from a patient with membranoproliferative nephritis (MPP), either by heating or by immune equivalence absorption, blocks C3 breakdown by C3NeF. Addition of purified factor B to these mixtures restores the anticomplementary effect. When purified factor B is added to mixtures of MPP and purified C3, breakdown also occurs. Associated with the C3 breakdown is a change in the electrophoretic mobility of factor B from the beta to the gamma position, a shift which has been associated with cleavage activation of the molecule. Further, serum factor B levels are often low in patients with membranoproliferative nephritis and bear a rough inverse correlation with C3NeF levels. It thus appears that factor B is the previously described heat-labile C3NeF cofactor. Whether the C3NeF reaction proceeds via a pathway comparable to that activated by the cobra venom factor or via that activated by zymosan or inulin cannot be determined from the present data. |
| Databáze: | OpenAIRE |
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