Cattaneo Irene, Choblet Sylvie, Valgardsdottir Rut, Roth Muriel, Massafra Annamaria, Beeg Marten, Gobbi Marco, Duonor-Cerutti Martine, Golay Josée
Division of Hematology, Center of Cellular Therapy "G. Lanzani", Azienda Socio Sanitaria Territoriale Papa Giovanni XXIII, 24122 Bergamo, Italy.
Centre National de la Recherche Scientifique UAR3426 "Baculovirus et Therapie", 30380 Saint-Christol-Lez-Alès, France.
Antibodies (Basel). 2024 Feb 20;13(1):15. doi: 10.3390/antib13010015.
We designed, produced, and purified a novel IgG1-like, bispecific antibody (bsAb) directed against B-cell maturation antigen (BCMA), expressed by multiple myeloma (MM) cells, and an immune checkpoint inhibitor (ICI), PDL1, expressed in the MM microenvironment. The BCMA×PDL1 bsAb was fully characterized in vitro. BCMA×PDL1 bound specifically and simultaneously, with nM affinity, to both native membrane-bound antigens and to the recombinant soluble antigen fragments, as shown by immunophenotyping analyses and surface plasmon resonance (SPR), respectively. The binding affinity of bsAb for PDL1 and BCMA was similar to each other, but PDL1 affinity was about 10-fold lower in the bsAb compared to parent mAb, probably due to the steric hindrance associated with the more internal anti-PDL1 Fab. The bsAb was also able to functionally block both antigen targets with IC in the nM range. The bsAb Fc was functional, inducing human-complement-dependent cytotoxicity as well as ADCC by NK cells in 24 h killing assays. Finally, BCMA×PDL1 was effective in 7-day killing assays with peripheral blood mononuclear cells as effectors, inducing up to 75% of target MM cell line killing at a physiologically attainable, 6 nM, concentration. These data provide the necessary basis for future optimization and in vivo testing of this novel bsAb.
我们设计、生产并纯化了一种新型的IgG1样双特异性抗体（bsAb），其靶向多发性骨髓瘤（MM）细胞表达的B细胞成熟抗原（BCMA）以及MM微环境中表达的免疫检查点抑制剂（ICI）程序性死亡配体1（PDL1）。对BCMA×PDL1双特异性抗体进行了全面的体外特性分析。免疫表型分析和表面等离子体共振（SPR）分别显示，BCMA×PDL1以纳摩尔亲和力特异性且同时结合天然膜结合抗原和重组可溶性抗原片段。双特异性抗体对PDL1和BCMA的结合亲和力彼此相似，但与亲本单克隆抗体相比，双特异性抗体中对PDL1的亲和力约低10倍，这可能是由于与更靠内的抗PDL1 Fab相关的空间位阻。该双特异性抗体还能够在纳摩尔范围内通过IC功能阻断两个抗原靶点。双特异性抗体的Fc具有功能，在24小时杀伤试验中可诱导人补体依赖性细胞毒性以及NK细胞介导的抗体依赖性细胞介导的细胞毒性（ADCC）。最后，在以外周血单个核细胞作为效应细胞的7天杀伤试验中，BCMA×PDL1有效，在生理可达到的6 nM浓度下可诱导高达75%的靶MM细胞系杀伤。这些数据为该新型双特异性抗体未来的优化和体内测试提供了必要依据。
