Harnessing antibody-driven bioconjugation to modulate immune function

About This Grant

Project Summary Our ability to manipulate primary immune cells has advanced treatments for many human malignancies. While extensive work has focused on developing genetic methods to engineer immune cells, chemical approaches remain underexplored. Chemically modifying disease-associated proteins or immune receptors offers a simple, modular, and cost-effective way to redirect cytotoxicity toward diseased cells. Such approach, however, requires organic transformations that can be performed in a crude biological milieu or in living organisms with precise molecular control. A few reactions meet these criteria, even fewer have been employed to transform primary immune cells. Additionally, the nature of the chemical modifications and geometry of the corresponding receptor-small molecule fusion are critical for facilitating optimal immune response. Therefore, developing bioconjugation strategy capable of modifying endogenous cell surface receptors, and introducing new functions, will not only enhance our ability to synthesize new biomolecules but also produce cell-based modalities for therapeutic applications. Herein, the proposed work introduces antibody-driven proximity bioconjugation to equip immune receptors with the ability to redirect and activate effector cells to specific targets. First, a panel of antibody conjugates, consisting of an electrophilic linker and a payload of choice, will be synthesized. The preparation of these reagents emphasizes modularity and balance between conjugate reactivity and stability. Mass spectrometry- based pipelines will be used to comprehensively analyze the conjugates’ ability to modify the target antigen in vitro and on cells. Reaction parameters, such as specificity and efficiency, will be correlated with the warhead’s reactivity and the antibody’s affinity, culminating into a roadmap for further optimization. Second, antibody- directed ligation will be employed to introduce small molecule adapters onto CCL-1, a key surface target of acute myeloid leukemia. This modification will enable molecular control over complementary anti-adapter CAR T cell activity and broadening therapeutic index. Finally, the programmability and modularity of the antibody-directed ligation will allow for the modification of various immune receptors with unique chemical elements. Combinatorial targeting will create opportunities for engaging multiple cooperative cell types and eliciting synergistic immune responses. Together, the proposed studies offer a creative and multidisciplinary solution to longstanding challenges in bioconjugation and engineered cell therapies. Beyond cytotoxic signaling, future work will focus on modifying and multiplexing immune receptors with agonists or antagonists to fine-tune downstream signaling. Additionally, extending antibody-directed ligation to transform other cell surface molecules will further catalyze the development of new therapeutics.