| Autor: |
Tax, W. J. M., Tamboer, W. P. M., Mensink, E. J. B. M., Koene, R. A. P. |
| Předmět: |
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| Zdroj: |
Scandinavian Journal of Immunology; Dec1996, Vol. 44 Issue 6, p571-577, 7p, 1 Diagram, 1 Chart |
| Abstrakt: |
Three classes of human leucocyte Fcγ receptors (hFcγR) have been identified so far: hFcγRI, hFcγRII, and hFcγRIII. Previous studies have demonstrated that genetically determined differences between individuals exist both with respect to the binding of murine IgG1 (mIgG1) to hFcγ receptors, and with respect to the binding of murine IgG2b (mIgG2b). The polymorphism in binding of mIgG1 could he ascribed to hFcγRIIA, an isoform of hFcγRII. The authors have now investigated whether one of the isoforms of hFcγRII is also responsible for the polymorphism in binding of mIgG2b. In these studies the authors used EBV-transformed human B cells that demonstrated either binding or no binding of mIgG2b in EA-rosetting assays, mRNA obtained from these cells was amplified by reverse transcriptase and polymerase chain reaction (RT-PCR). Hybridization experiments with the RT-PCR products revealed that the hFcγRIIB but not the hFcγRIIA isoform was present in these cells. DNA sequencing further demonstrated that the nucleotide sequence of both the extracellular part and the cytoplasmic moiety of hFcγRIIB was identical for all individuals tested, regardless of their ability to bind mIgG2b. These findings indicate that the polymorphic binding of mIgG2b cannot be ascribed to one of the isoforms of hFcγRII. Since hFcγRI and hFcγRIII are not present on the cell surface of these cells, the authors conclude that an Fc receptor different from the known hFcγ receptors must be responsible for the polymorphic binding of mIgG2b. These data further expand the complexity of hFcγR. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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