IL-4 plus CD40 monoclonal antibody induces human B cells gamma subclass-specific isotype switch: switching to gamma 1, gamma 3, and gamma 4, but not gamma 2.
IL-4 plus CD40 monoclonal antibody induces human B cells gamma subclass-specific isotype switch: switching to gamma 1, gamma 3, and gamma 4, but not gamma 2.
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DOI：
10.4049/jimmunol.155.5.2318
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发表时间：
1995-09
影响因子：
4.4
通讯作者：
S. Fujieda;K. Zhang;A. Saxon
中科院分区：
文献类型：
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作者：
S. Fujieda;K. Zhang;A. Saxon
已知用IL-4加CD 40 mAb刺激可诱导IgE和IgG 4的产生。在这项研究中，我们确定了IgG亚类特异性IL-4 + CD 40单抗刺激人纯化B细胞。我们确定了真正的体外开关开关的开关环状DNA（S γ/S亩）的产生代表主要的S亩/S γ事件和生产的γ亚类特异性生殖系转录物的组合，逆转录-PCR和限制性内切酶消化。我们同时测量产生的IgG亚类蛋白水平的变化。对42个环状开关DNA克隆进行鉴定和测序。通过分析关键的S γ核苷酸来确定S γ/S μ嵌合PCR产物中S γ片段的IgG亚类。发现开关缺失的克隆由S γ 1/S μ、S γ 3/S μ和S γ 4/S μ嵌合开关序列组成，表明已经发生了这种开关。没有发现S γ 2/S μ嵌合开关序列，虽然在S γ/S μ断裂点处没有鉴定出共有序列，但在断裂点附近的S γ区域中明显存在四个连续的鸟嘌呤（GGGG）。人纯化B细胞中γ 1、γ 3和γ 4转换环的诱导伴随着IgG 1、IgG 3和IgG 4的产生增强，但不伴随IgG 2。类似地，单独用IL-4刺激诱导γ 1、γ 3和γ 4但不诱导γ 2生殖系转录物。这些结果表明，IL-4加CD 40 mAb诱导IG同种型从μ转变为γ 1、γ 3和γ 4，但不转变为γ 2。
Stimulation with IL-4 plus CD40 mAb is known to induce production of IgE and IgG4. In this study, we determined the IgG subclass specificity of IL-4 plus CD40 mAb stimulation for human purified B cells. We determined true in vitro switching by the generation of switch circular DNA (S gamma/S mu) representing primary S mu/S gamma events and production of gamma subclass-specific germ-line transcripts by a combination of reverse transcription-PCR and restriction endonuclease digestion. We simultaneously measured changes in the levels of IgG subclass proteins produced. Forty-two clones of circular switch DNA were identified and sequenced. The IgG subclass of S gamma fragment in the S gamma/S mu chimeric PCR products was determined by analyzing key S gamma nucleotides. The switch-deleted clones were found to consist of S gamma 1/S mu, S gamma 3/S mu, and S gamma 4/S mu chimeric switch sequences, showing that such switching had occurred. No S gamma 2/S mu chimeric switch sequences were found. While a consensus sequence was not identified at the S gamma/S mu breakpoints, four contiguous guanines (GGGG) were noticeably present in the S gamma region near the breakpoint. The induction of gamma 1, gamma 3, and gamma 4 switch circles in human purified B cells was accompanied by enhanced production of IgG1, IgG3, and IgG4 but not IgG2. Similarly, stimulation with IL-4 alone induced gamma 1, gamma 3, and gamma 4 but not gamma 2 germ-line transcripts. These results demonstrate that IL-4 plus CD40 mAb induces Ig isotype switch from mu to gamma 1, gamma 3, and gamma 4 but not to gamma 2.