کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2830678 | 1163749 | 2015 | 11 صفحه PDF | دانلود رایگان |
• Germinal center reaction in spleen.
• Active induction of somatic hypermutation in IgM.
• Down-regulation of class-switch recombination.
During a T cell-dependent immune response, B cells undergo clonal expansion and selection and the induction of isotype switching and somatic hypermutation (SHM). Although somatically mutated IgM+ memory B cells have been reported, it has not been established whether they are really high affinity B cells. We tracked (4-hydroxy-3-nitrophenyl) acetyl hapten-specific GC B cells from normal immunized mice based on affinity of their B cell receptor (BCR) and performed BCR sequence analysis. SHM was evident by day 7 postimmunization and increased with time, such that high affinity IgM+ as well as IgG+ memory B cells continued to be generated up to day 42. In contrast, class-switch recombination (CSR) was almost completed by day 7 and then the ratio of IgG1+/IgM+ GC B cells remained unchanged. Together these findings suggest that IgM+ B cells undergo SHM in the GC to generate high affinity IgM+ memory cells and that this process continues even after CSR is accomplished.
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Journal: Molecular Immunology - Volume 68, Issue 2, Part C, December 2015, Pages 617–627