Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, United States.
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, United States.
Elife. 2021 Jan 13;10:e64281. doi: 10.7554/eLife.64281.
Mapping polyclonal serum responses is critical to rational vaccine design. However, most high-resolution mapping approaches involve isolating and characterizing individual antibodies, which incompletely defines the polyclonal response. Here we use two complementary approaches to directly map the specificities of the neutralizing and binding antibodies of polyclonal anti-HIV-1 sera from rabbits immunized with BG505 Env SOSIP trimers. We used mutational antigenic profiling to determine how all mutations in Env affected viral neutralization and electron microscopy polyclonal epitope mapping (EMPEM) to directly visualize serum Fabs bound to Env trimers. The dominant neutralizing specificities were generally only a subset of the more diverse binding specificities. Additional differences between binding and neutralization reflected antigenicity differences between virus and soluble Env trimer. Furthermore, we refined residue-level epitope specificity directly from sera, revealing subtle differences across sera. Together, mutational antigenic profiling and EMPEM yield a holistic view of the binding and neutralizing specificity of polyclonal sera.
对多克隆血清反应进行作图对于合理的疫苗设计至关重要。然而，大多数高分辨率作图方法都涉及到分离和表征单个抗体，这不能完全定义多克隆反应。在这里，我们使用两种互补的方法，直接绘制用 BG505 Env SOSIP 三聚体免疫的兔子的多克隆抗 HIV-1 血清的中和和结合抗体的特异性。我们使用突变抗原分析来确定 Env 中的所有突变如何影响病毒中和，并用电子显微镜多克隆表位作图（EMPEM）直接观察到与 Env 三聚体结合的血清 Fabs。主要的中和特异性通常只是更广泛的结合特异性的一个子集。结合和中和之间的差异反映了病毒和可溶性 Env 三聚体之间的抗原性差异。此外，我们还从血清中直接细化了残基水平的表位特异性，揭示了血清之间的细微差异。总之，突变抗原分析和 EMPEM 提供了多克隆血清结合和中和特异性的整体视图。
