ANALYSIS OF THE B-CELL PROGENITOR COMPARTMENT AT THE LEVEL OF SINGLE CELLS
ANALYSIS OF THE B-CELL PROGENITOR COMPARTMENT AT THE LEVEL OF SINGLE CELLS
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DOI：
10.1016/s0960-9822(00)00129-9
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发表时间：
1994-07-01
期刊：
影响因子：
9.2
通讯作者：
RAJEWSKY, K
中科院分区：
文献类型：
--
作者：
EHLICH, A;MARTIN, V;RAJEWSKY, K
背景资料：在小鼠B细胞发育期间，免疫球蛋白重链（IgH）基因座的V-H、D-H和J（H）元件重排，首先通过D-H-J（H）连接，然后通过V-H-D（H）J（H）连接。在阅读框2（三个可能的D-H阅读框之一）中的框内（“生产性”）V（H）D（H）J（H）接头和D（H）J（H）接头分别允许表达mu和截短的mu链（D mu蛋白）。从一个细胞的两个IgH基因座之一的这种分子的表达被认为是干扰V-H-D（H）J（H）重组的另一个IgH基因座上，并引导细胞通过进一步development.Results：我们已经开发了一种基因扩增检测，允许检查重排的免疫球蛋白基因在单细胞。使用该测定，我们在发育的早期阶段监测具有D（H）J（H）和/或V（H）D（H）J（H）关节的细胞：在通过流式细胞术细分为A、B、C和C'级分的CD 43（+）B细胞祖细胞中，以及在CD 43（-）前B细胞（级分D）中。组分C富集具有两个非生产性V（H）D（H）J（H）接合的细胞。在任何部分中均未观察到在D-H阅读框架2中含有D（H）J（H）关节和V（H）D（H）J（H）关节的细胞。所有组分D细胞都具有框内V（H）D（H）J（H）接头。结论：表达D μ蛋白的细胞在发育过程中由于V-H-D（H）J（H）连接的抑制而受到抑制。成熟为CD 43（-）前B细胞需要表达μ链;因此，携带两个非生产性V（H）D（H）J（H）关节的细胞在CD 43（+）隔室中积累。这种发育停滞也可能影响表达自身反应性V（H）D（H）J（H）抗体结构域的细胞。我们的研究结果进一步表明，等位基因排斥在IgH基因座已经建立在前B细胞阶段。
Background: During B-cell development in the mouse, the V-H, D-H and J(H) elements of the immunoglobulin heavy chain (IgH) locus are rearranged, firstly by D-H-J(H) joining, and then by V-H-D(H)J(H) joining. In-frame ('productive') V(H)D(H)J(H) joints and D(H)J(H) joints in reading frame 2 (one of the three possible D-H reading frames) allow the expression of mu and truncated mu chains (D mu proteins), respectively. The expression of such molecules from one of the two IgH loci of a cell is thought to interfere with V-H-D(H)J(H) recombination on the other IgH locus, and to guide the cells through further development.Results: We have developed a gene amplification assay that permits the examination of rearranged immunoglobulin genes in single cells. Using this assay, we monitored cells bearing D(H)J(H) and/or V(H)D(H)J(H) joints at early stages of development: in CD43(+) B-cell progenitors, subdivided into fractions A, B, C and C' by flow cytometry, and in CD43(-) pre-B cells (fraction D). Fraction C was enriched for cells with two non-productive V(H)D(H)J(H) joints. Cells containing both a D(H)J(H) joint in D-H reading frame 2 and a V(H)D(H)J(H) joint were not seen in any fraction. All fraction D cells harbored an in-frame V(H)D(H)J(H) joint. Cells with two productive V(H)D(H)J(H) joints appear to be selected against throughout development.Conclusions: Cells expressing D mu proteins appear to be arrested in development as a result of inhibited V-H-D(H)J(H) joining. Expression of the mu chain is required for maturation into CD43(-) pre-B cells; accordingly, cells carrying two non-productive V(H)D(H)J(H) joints accumulate in the CD43(+) compartment. Such a developmental arrest may also affect cells that express self-reactive V(H)D(H)J(H) antibody domains. Our results indicate further that allelic exclusion at the IgH locus is already established at the pre-B cell stage.