Department of Chemical Engineering, Institute for Cellular and Molecular Biology, Section of Molecular Genetics and Microbiology, Center for Systems and Synthetic Biology, Department of Biomedical Engineering, Department of Chemistry and Biochemistry, and Applied Research Laboratories, University of Texas at Austin, Austin, TX 78712-1062.
Proc Natl Acad Sci U S A. 2014 Feb 11;111(6):2259-64. doi: 10.1073/pnas.1317793111. Epub 2014 Jan 27.
Most vaccines confer protection via the elicitation of serum antibodies, yet more than 100 y after the discovery of antibodies, the molecular composition of the human serum antibody repertoire to an antigen remains unknown. Using high-resolution liquid chromatography tandem MS proteomic analyses of serum antibodies coupled with next-generation sequencing of the V gene repertoire in peripheral B cells, we have delineated the human serum IgG and B-cell receptor repertoires following tetanus toxoid (TT) booster vaccination. We show that the TT(+) serum IgG repertoire comprises ∼100 antibody clonotypes, with three clonotypes accounting for >40% of the response. All 13 recombinant IgGs examined bound to vaccine antigen with Kd ∼ 10(-8)-10(-10) M. Five of 13 IgGs recognized the same linear epitope on TT, occluding the binding site used by the toxin for cell entry, suggesting a possible explanation for the mechanism of protection conferred by the vaccine. Importantly, only a small fraction (<5%) of peripheral blood plasmablast clonotypes (CD3(-)CD14(-)CD19(+)CD27(++)CD38(++)CD20(-)TT(+)) at the peak of the response (day 7), and an even smaller fraction of memory B cells, were found to encode antibodies that could be detected in the serological memory response 9 mo postvaccination. This suggests that only a small fraction of responding peripheral B cells give rise to the bone marrow long-lived plasma cells responsible for the production of biologically relevant amounts of vaccine-specific antibodies (near or above the Kd). Collectively, our results reveal the nature and dynamics of the serological response to vaccination with direct implications for vaccine design and evaluation.
大多数疫苗通过诱导血清抗体来提供保护，但在发现抗体 100 多年后，人类针对抗原的血清抗体库的分子组成仍然未知。我们使用血清抗体的高分辨率液相色谱串联质谱蛋白质组学分析和外周 B 细胞 V 基因库的下一代测序，描绘了破伤风类毒素 (TT) 加强疫苗接种后的人血清 IgG 和 B 细胞受体库。我们表明，TT(+)血清 IgG 库由约 100 种抗体克隆型组成，其中 3 种克隆型占反应的>40%。所有 13 种检查的重组 IgG 都与疫苗抗原结合，Kd 值约为 10(-8)-10(-10) M。13 种 IgG 中有 5 种识别 TT 上的相同线性表位，阻断了毒素用于细胞进入的结合位点，这表明了疫苗提供保护的机制的一种可能解释。重要的是，在反应高峰（第 7 天）时，外周血浆母细胞克隆型（CD3(-)CD14(-)CD19(+)CD27(++)CD38(++)CD20(-)TT(+)）中只有一小部分（<5%）和记忆 B 细胞中，编码的抗体可以在接种疫苗 9 个月后的血清学记忆反应中被检测到。这表明只有一小部分反应性外周 B 细胞产生骨髓内长寿浆细胞，负责产生具有生物学意义的大量疫苗特异性抗体（接近或高于 Kd）。总的来说，我们的结果揭示了疫苗接种引起的血清反应的性质和动态，这对疫苗设计和评估具有直接影响。
