Bispecific antibody Armed activated T cells exhibit time-dependent co-expression patterns of inhibitory ligands and gene expression programs

Abstract Immunotherapy success has been limited in treating solid tumors. Bispecific antibody Armed activated T cell (BATs) therapy activates, expands, and arms patient cells ex vivowith bispecific antibodies (BiAb) to produce a “drug” that combines non-MHC restricted cytotoxicity of specificity BiAb. BATs promises improve survival patients with metastatic breast, prostate, pancreatic cancer without dose limiting toxicities. However, the anti-tumor potency varies between decreases time. Understanding mechanisms behind this decrease will help identify therapeutic combinations dosing strategies maximize response. Low effector:target coculture conditions allowing target escape from BAT killing were identified. function was measured by cytotoxicity, flow cytometry, RNA sequencing. Samples taken at set timepoints dynamic representation functional changes conditions. We observed time-dependent co-expression inhibitory ligands BATs, including increased PD-1 LAG3 during first 24h coculture, followed TIGIT later timepoints. RNA-seq revealed upregulation genes associated dysfunction, NR4A checkpoint proteins TIGIT, LAG3, PD-1, as early 1 hr coculture. These findings integrated into mechanistic model BAT-target interactions. Our demonstrated emergence therapeutically targetable receptors, suggesting optimizing targets administration times may synergistic immunotherapy combination outcomes.