No cytotoxicity of AbTCR-CSR was observed against normal PBMCs. Mock T cells, CSR (with irrelevant Fab AbTCR), ESK2 AbTCR-CSR clone no. 18, or AbTCR-CSR clone no. 34 were incubated with (A) CFSE-labeled AML-14 (as a positive control), (B) PBMCs from HLA-A2 positive donor, or (C) negative donor at an E:T ratio of 1:1, overnight. The cells were harvested, washed, and stained with mAb to CD33 and zombie dye (to stain dead cells) and analyzed by flow cytometry. (D) The flow plots show a representative profile of CD33 vs CFSE double-positive cells and the percentage of CD33⁺ cell death was summarized. (E) In the same experiments, CFSE⁺ target PBMCs were also stained with CD3 and CD19 and the percentage of each lineage cells are shown in bar graphs. The data represent 1 of 4 separate experiments with different donors.