| First Author | Luan JJ | Year | 1996 |
| Journal | J Immunol | Volume | 157 |
| Issue | 10 | Pages | 4707-16 |
| PubMed ID | 8906852 | Mgi Jnum | J:37198 |
| Mgi Id | MGI:84519 | Doi | 10.4049/jimmunol.157.10.4707 |
| Citation | Luan JJ, et al. (1996) Defective Fc gamma RII gene expression in macrophages of NOD mice: genetic linkage with up-regulation of IgG1 and IgG2b in serum. J Immunol 157(10):4707-16 |
| abstractText | A quantitative trait locus for increased Ige serum levels in the NOD mouse strain was mapped to distal chromosome 1, close to the fcgr2 locus encoding the low-affinity type II receptor for the Fc portion of IgG (Fc gamma RII), Expression of membrane-inserted (b2) and soluble (b3) isoforms of Fc gamma RII was strongly decreased in macrophages of NOD compared with C57BL/6 (B6) mice. In contrast, B cell-specific (Fc gamma RIIb1) isoform was only slightly decreased and Fc gamma RIII was not altered. This Fc gamma RII regulatory defect was cis-encoded by fcgr2 or by a closely linked locus, occurred at the mRNA level, and was associated with multiple mutations in the fcgr2 gene promoter. In relation with this defect, binding of IgG1- and IgG2b- but not IgG2a-opsonized RBC by macrophages of NOD and congenic B6.NOD-fcgr2 mice was severely impaired, but was normal in macrophages of NOD.B6- fcgr2 congenic mice, indicating that Fc gamma RII plays a nondispensable role in binding of IgG1 and IgG2b isotypes. Likewise, serum levels of IgG1 and IgG2b but not IgG2a were up-regulated in NOD compared with NOD.B6-fcgr2 congenic mice. These findings indicate that macrophage Fc gamma RII may regulate serum IgG1 and IgG2b through their catabolism, and validate the NOD strain as a model to investigate the functions of Fc gamma RII isoforms. |
