Antigen-independent appearance of recombination activating gene (RAG)-positive bone marrow B cells in the spleens of immunized mice.
Antigen-independent appearance of recombination activating gene (RAG)-positive bone marrow B cells in the spleens of immunized mice.
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DOI：
10.1084/jem.192.12.1745
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发表时间：
2000-12-18
影响因子：
15.3
通讯作者：
Seidl, K J
中科院分区：
文献类型：
--
作者：
Gartner, F;Alt, F W;Monroe, R J;Seidl, K J
在鸡γ球蛋白偶联的4-羟基-3-硝基苯乙酰(NP-CGG)和佐剂氢氧化铝(明胶)免疫的小鼠中，表达重组激活基因(RAG+)的小鼠脾B系细胞被认为是成熟的B细胞，在生发中心(GC)遇到抗原后重新表达RAG，这一观点得到了体外激活的外周B淋巴细胞群RAG表达的研究结果的支持。然而，最近的研究表明，这些细胞可能是尚未消除RAG表达的未成熟B细胞。在这里，我们使用RAG2-绿色荧光蛋白(GFP)融合基因敲入小鼠来证明单独给药后RAG+B系细胞确实出现在脾中，并且它们的出现不依赖于T细胞通过CD40途径的相互作用。此外，在过继转移骨髓(BM)细胞的RAG2缺陷小鼠中，可检测到RAG+B系细胞，但不能检测到RAG+小鼠的脾细胞。尽管脾RAG+B细胞表达与GC B细胞相关的表面标志，但我们也在祖细胞/前体BM B细胞上发现了相同的基本标志。最后，在有丝分裂原(脂多糖和抗−)和细胞因子(IL[IL]-4和IL-7)的体外刺激下，我们没有检测到RAG基因的表达。总之，我们的研究表明，来自骨髓的RAG+B系细胞在免疫后在脾中积聚，这种积聚不是抗原特异性反应的结果。
Splenic B lineage cells expressing recombination activation genes (RAG+) in mice immunized with 4-hydroxy-3-nitrophenyl-acetyl coupled to chicken γ-globulin (NP-CGG) and the adjuvant aluminum-hydroxide (alum) have been proposed to be mature B cells that reexpress RAG after an antigen encounter in the germinal center (GC), a notion supported by findings of RAG expression in peripheral B lymphocyte populations activated in vitro. However, recent studies indicate that these cells might be immature B cells that have not yet extinguished RAG expression. Here, we employ RAG2–green fluorescent protein (GFP) fusion gene knock-in mice to show that RAG+ B lineage cells do appear in the spleen after the administration of alum alone, and that their appearance is independent of T cell interactions via the CD40 pathway. Moreover, splenic RAG+ B lineage cells were detectable in immunized RAG2-deficient mice adoptively transferred with bone marrow (BM) cells, but not with spleen cells from RAG+ mice. Although splenic RAG+ B cells express surface markers associated with GC B cells, we also find the same basic markers on progenitor/precursor BM B cells. Finally, we did not detect RAG gene expression after the in vitro stimulation of splenic RAG− mature B cells with mitogens (lipopolysaccharide and anti-CD40) and cytokines (interleukin [IL]-4 and IL-7). Together, our studies indicate that RAG+ B lineage cells from BM accumulate in the spleen after immunization, and that this accumulation is not the result of an antigen-specific response.