Department of Bioengineering, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
Proc Natl Acad Sci U S A. 2011 Mar 29;108(13):5348-53. doi: 10.1073/pnas.1014277108. Epub 2011 Mar 10.
It is thought that the adaptive immune system of immature organisms follows a more deterministic program of antibody creation than is found in adults. We used high-throughput sequencing to characterize the diversifying antibody repertoire in zebrafish over five developmental time points. We found that the immune system begins in a highly stereotyped state with preferential use of a small number of V (variable) D (diverse) J (joining) gene segment combinations, but that this stereotypy decreases dramatically as the zebrafish mature, with many of the top VDJ combinations observed in 2-wk-old zebrafish virtually disappearing by 1 mo. However, we discovered that, in the primary repertoire, there are strong correlations in VDJ use that increase with zebrafish maturity, suggesting that VDJ recombination involves a level of deterministic programming that is unexpected. This stereotypy is masked by the complex diversification processes of antibody maturation; the variation and lack of correlation in full repertoires between individuals appears to be derived from randomness in clonal expansion during the affinity maturation process. These data provide a window into the mechanisms of VDJ recombination and diversity creation and allow us to better understand how the adaptive immune system achieves diversity.
据认为，不成熟生物体的适应性免疫系统遵循的抗体产生程序比成年生物体更具确定性。我们使用高通量测序技术在五个发育时间点表征了斑马鱼多样化的抗体库。我们发现免疫系统以高度定型的状态开始，优先使用少数 V（可变）D（多样）J（连接）基因片段组合，但随着斑马鱼成熟，这种定型性急剧下降，在 2 周大的斑马鱼中观察到的许多顶级 VDJ 组合到 1 个月时几乎消失。然而，我们发现，在初级库中，VDJ 的使用存在强烈的相关性，并且随着斑马鱼的成熟而增加，这表明 VDJ 重组涉及到一种出乎意料的确定性编程水平。这种定型性被抗体成熟的复杂多样化过程所掩盖；个体之间完整库中的变化和缺乏相关性似乎源于亲和力成熟过程中克隆扩增的随机性。这些数据为 VDJ 重组和多样性创造的机制提供了一个窗口，并使我们能够更好地理解适应性免疫系统如何实现多样性。
