Efficient development of fully human monoclonal antibodies by rapid mRNA immunization of humanized mice followed by single B cell sequencing

As a clinical vaccine, lipid nanoparticle (LNP) mRNA demonstrated potent and broad antibody responses, leading to speculation about its potential for antibody discovery. Here, we developed RAMIHM, a highly efficient strategy for developing fully human monoclonal antibodies that employs rapid mRNA immunization of humanized mice followed by single B cell sequencing (scBCR-seq). We immunized humanized transgenic mice with RAMIHM and generated 15 top-ranked clones from peripheral blood, plasma B, and memory B cell populations, demonstrating a high rate of antigen-specificity (93.3%). Two Omicron-specific neutralizing antibodies with high potent and one broad-spectrum neutralizing antibody were discovered. Furthermore, we extended the application of RAMIHM to cancer immunotherapy targets, including a single transmembrane protein CD22 and a multi-transmembrane GPCR target, GPRC5D, which is difficult for traditional protein immunization methods. RAMIHM-scBCR-seq is a broadly applicable platform for the rapid and efficient development of fully human monoclonal antibodies against an assortment of targets.

作为一款临床用疫苗，脂质纳米颗粒（lipid nanoparticle, LNP）mRNA展现出强效且广谱的抗体应答能力，由此引发了其在抗体发现领域应用潜力的相关推测。本研究开发了RAMIHM这一高效全人源单克隆抗体制备策略：该策略先对人源化小鼠进行快速mRNA免疫，随后结合单B细胞测序（single B cell sequencing, scBCR-seq）。我们利用RAMIHM对人源化转基因小鼠进行免疫，并从外周血、浆B细胞及记忆B细胞群中获得15株优质克隆，经检测其抗原特异性率高达93.3%。本研究共发现2株强效奥密克戎（Omicron）特异性中和抗体，以及1株广谱中和抗体。此外，我们将RAMIHM的应用范围拓展至肿瘤免疫治疗靶点，包括单次跨膜蛋白CD22，以及传统蛋白免疫方法难以靶向的多跨膜G蛋白偶联受体（G protein-coupled receptor, GPCR）靶点GPRC5D。综上，RAMIHM-scBCR-seq是一款普适性强的平台技术，可用于快速高效地针对各类靶点开发全人源单克隆抗体。