Optimizing Tri-TAC Design for Enhanced T Cell Functionality

Example 3

FIG. 10A-FIG. 10B illustrate several TAC variants with different linkers connecting the ligand that binds a TCR complex and the target-binding ligand domain. The flexible connector allows movement between the two domains. The large domain connector contains two folded domains and is very large and rigid. The small and long helix connectors also introduce rigidity but are less restrictive when compared to the large domain linker.

FIG. 11A-FIG. 11E illustrate the impact of connector substitution on Tri-TAC surface expression, Tri-TAC transduction efficiency, and cytokine production upon Tri-TAC ligation. FIG. 11A and FIG. 11B show that the helical linkers enhance surface expression and transduction efficiency when compared to the flexible linker, while the large domain connector enhances transduction efficiency but not surface expression. FIG. 11D, FIG. 11E illustrates cytokine production by cells expressing Tri-TACs with short helix, long helix, or large domain connectors.

FIG. 12A illustrates enhanced in vitro cytotoxicity of T cells expressing Tri-TACs with the short helix connector. FIG. 12B illustrates enhanced in vivo tumor control of T cells expressing Tri-TACs with the short helix connector. The short helical connector was associated with high in vitro cytotoxicity and effective in vivo tumor control.