| First Author | Lajaunias F | Year | 2002 |
| Journal | J Immunol | Volume | 168 |
| Issue | 12 | Pages | 6078-83 |
| PubMed ID | 12055217 | Mgi Jnum | J:123796 |
| Mgi Id | MGI:3719544 | Doi | 10.4049/jimmunol.168.12.6078 |
| Citation | Lajaunias F, et al. (2002) Differentially regulated expression and function of CD22 in activated B-1 and B-2 lymphocytes. J Immunol 168(12):6078-83 |
| abstractText | CD22 is a B cell-restricted transmembrane protein that apparently controls signal transduction thresholds initiated through the B cell Ag receptor (BCR) in response to Ag. However, it is still poorly understood how the expression of CD22 is regulated in B cells after their activation. Here we show that the expression levels of CD22 in conventional B-2 cells are markedly down-regulated after cross-linking of BCR with anti-IgM mAb but are up-regulated after stimulation with LPS, anti-CD40 mAb, or IL-4. In contrast, treatment with anti-IgM mAb barely modulated the expression levels of CD22 in CD5(+) B-1 cells, consistent with a weak Ca(2+) response in anti-IgM-treated CD5(+) B-1 cells. Moreover, in CD22-deficient mice, anti-IgM treatment did not trigger enhanced Ca(2+) influx in CD5(+) B-1 cells, unlike CD22-deficient splenic B-2 cells, suggesting a relatively limited role of CD22 in BCR signaling in B-1 cells. In contrast, CD22 levels were markedly down-regulated on wild-type B-1 cells in response to LPS or unmethylated CpG-containing oligodeoxynucleotides. These data indicate that the expression and function of CD22 are differentially regulated in B-1 and conventional B-2 cells, which are apparently implicated in innate and adaptive immunity, respectively. |
