Calcium-loaded erythrocytes have a defect in complement regulation distinct from that resulting from exposure to 2- aminoethylisothiouronium bromide
| Autor: | ST Test, J Mitsuyoshi |
|---|---|
| Rok vydání: | 1995 |
| Předmět: | |
| Zdroj: | Blood. 86:2799-2806 |
| ISSN: | 1528-0020 0006-4971 |
| DOI: | 10.1182/blood.v86.7.2799.bloodjournal8672799 |
| Popis: | Calcium-loaded red blood cells (RBCs) previously have been shown to have an increased sensitivity to complement-mediated hemolysis and particularly to lysis mediated by the C5b-9 membrane attack complex (MAC) of complement. Because RBCs exposed to 2-aminoethylisothiouronium bromide (AET) also have been shown to be particularly sensitive to the MAC, a direct comparison of calcium-loaded and AET-treated RBCs was performed. Calcium-loaded and AET-treated RBCs shared a marked increase in sensitivity to lysis by the MAC in two different assays. However, measurements of C5b-7 and C9 binding suggested that different mechanisms were responsible. AET-treated RBCs showed an increase in C9 binding and an increased C9/C7 ratio consistent with functional loss of CD59/membrane inhibitor of reactive lysis (MIRL). In contrast, calcium-loaded RBCs had minimally increased C9 binding that resulted in C9/C7 ratios that were less than those for untreated RBCs, suggesting that CD59/MIRL inactivation had not occurred. When RBCs were incubated in acidified serum, AET-treated cells demonstrated a marked increase in C3b binding and hemolysis that was observed in neither control nor calcium-loaded RBCs. These results suggest that the underlying lesions responsible for an increase in susceptibility to complement-mediated hemolysis are different for calcium-loaded and AET-treated RBCs. |
| Databáze: | OpenAIRE |
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