Bispecific Antibodies Produced via Chemical Site-Specific Conjugation Technology: AJICAP Second Generation

Bispecific antibodies are biotherapeutics that amalgamate the specificities of two distinct antibodies into one molecule. Bispecific antibodies can be utilized in a broad range of diagnostic and therapeutic applications; however, their engineering requires genetic modification and remains time-consuming. Therefore, in this study, we used AJICAP second-generation technology, which drives the production of site-specific antibody-drug conjugates in a practical and robust manner, without genetic modification requirements, to generate bispecific antibodies. Using haloketone chemistry as an alternative to maleimide chemistry, which carries reaction risks, we successfully produced site-specific antibody conjugates. Pharmacokinetic studies revealed that the haloketone-based antibody conjugate was stable in the rat plasma. The resultant bispecific antibodies were rigorously evaluated, and surface plasmon resonance measurements and flow cytometry analyses confirmed that antigen binding remained intact. Additionally, the affinity for the neonatal Fc receptor (FcRn) was retained after conjugation. Further cytotoxicity evaluation emphasized the pronounced activity of the generated bi-specific antibodies. These preliminary findings highlight the potential of AJICAP second-generation technology in BisAb production. This novel approach introduces a fully chemical, site-specific strategy capable of producing bispecific antibodies, heralding a new era in the field of biotherapeutics.