Abstract 6361: KY-HC-mouse: A low-cost and rapid nanobody discovery platform

Abstract

Abstract Nanobodies, primarily derived from camelid animals, have gained prominence in antibody-drug development due to their small molecular weight and ease of modification. However, the high cost associated with camelid animals for nanobody discovery led us to develop a strain of heavy-chain mice known as KY-HC-mouse. This genetically modified mouse expresses IgG without the CH1 domain, resulting in the production of nanobodies in IgG format. Utilizing hybridoma techniques, we developed a variety of nanobodies against multiple targets, such as PSMA, CD38, PD-L1, CD28, and 4-1BB, from KY-HC-mouse. These nanobodies all demonstrate high affinity, with KD ranging from 0.01 nM to 10 nM. We also selected antagonist nanobodies that block the interaction of PD1 and PDL1, as well as agonist nanobodies that stimulate 4-1BB signaling in T cells. After humanization, most nanobodies have a half-life of more than five days in the blood of both mice and monkeys. Subjected to various treatments, such as high concentration, low pH, repeated freezing and thawing, and high temperature, most humanized nanobodies show neither aggregation nor degradation, suggesting good developability of these nanobodies. Finally, we have developed multiple bispecific antibodies (BsAbs) targeting both PDL1 and 4-1BB, PSMA and 4-1BB, or B7H3 and 4-1BB. These BsAbs exhibit good developability and efficacy. In conclusion, our KY-HC-mouse is a powerful nanobody discovery platform. Citation Format: Guojin Wu, Feng Hao, Feng He, Hao Peng, Yi Gu, Jinying Ning. KY-HC-mouse: A low-cost and rapid nanobody discovery platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6361.