Profiling target binding interactions for T-cell activation in CAR-T cell cancer immunotherapy
Advisor: Frank Zhang
In acute myeloid leukemia (AML), tumor cells have been shown to overexpress the PR1 peptide on the HLA-A2 antigen of their surfaces. Chimeric antigen receptor therapy of T cells (CAR-T cell therapy) has been recently proven to be an effective approach in destroying cancer cells in a variety of blood diseases and lymphoid malignancies. Despite the successes of this new immunotherapy, little is known about the mechanical binding forces responsible for T-cell activation. Here, we have acquired a CAR-T cell engineered with a humanized 8F4 (h8F4) antibody designed to bind specifically to the PR1/HLA-A2 protein complex. While h8F4 CAR-T cells have been shown to be effective in targeting and killing AML cells in cell culture plates, we have introduced a more physiological flow assay to replicate the mechanically stimulating environment of the human body. Furthermore, we have utilized atomic force microscopy (AFM) to profile the binding affinity of the PR1/CAR-T interaction. To create an effective range of rupture forces for the binding interaction, different loading rates were applied to pull apart the complex. While we have demonstrated the CAR-T to have a specific binding interaction for the PR1 peptide, we also recognized the LFA1/I-CAM1 interaction as a potential T-cell activator mechanism. LFA1, a native adhesion molecule on the CAR-T cell, elicits a specific interaction with the intercellular adhesion molecule 1 (I-CAM1) of the tumor cell surface. Atomic force microscopy confirmed the LFA1/I-CAM-1 binding mechanism to have a rupture force about 1.5 times stronger than the PR1/CAR-T interaction. These results indicate the possibility of co-activating mechanical forces responsible for T-cell activation and tumor cell elimination.
About Liam Dow:
Liam Dow, from West Newbury, MA, is a junior bioengineering student conducting research in atomic force microscopy and mechanotransduction under the direction of Frank Zhang. Outside of the lab, Liam is passionate about playing both piano and guitar. His love of the outdoors has also directed him towards activities such as rock climbing, hiking, and running. After he graduates with a B.S. in bioengineering, he plans to explore deeper into the world of research and pursue a PhD.