AUTHOR=Mohan Nishant , Ayinde Safiat , Peng Hanjing , Dutta Shraboni , Shen Yi , Falkowski Vincent M. , Biel Thomas G. , Ju Tongzhong , Wu Wen Jin 

TITLE=Structural and functional characterization of IgG- and non-IgG-based T-cell-engaging bispecific antibodies

JOURNAL=Frontiers in Immunology

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1376096

DOI=10.3389/fimmu.2024.1376096

ISSN=1664-3224

ABSTRACT=Bispecific T-cell engaging antibodies are a growing class of therapeutics with numerous molecules being tested in clinical trials, and currently seven of them have received market approval. They are structurally complex and function as adaptors to redirect the cytotoxicity of T-cells to kill tumor cells. T-cell engaging bispecific antibodies can be generally divided into two categories: IgG/IgG-like format and non-IgG-like format. Different formats may have different intrinsic potencies and physiochemical properties, and comprehensive studies are needed to gain a better understanding of how the differences in formats impact on structural and functional characteristics. In this study, we designed and generated bispecific T-cell engaging antibodies with IgG-like (DVD-Ig) and non-IgG (BiTE) formats. Both target the same pair of antigens (EGFR and CD3) to minimize the possible influence of targets on functional characterization. We performed a side-by-side comparison to assess differences in the physiochemical and biological properties of these two bispecific T-cell engaging antibodies using a variety of breast and ovarian cancer cell-based functional assays to delineate the structural-functional relationships and anti-tumor activities/potency. We found that the Fc portion of T-cell engaging bispecific antibodies can significantly impact antigen binding activity, potency, and stability in addition to eliciting different mechanisms of action that contribute the killing of cancer cells.