Fig. 1.

SNUC cell lines are modestly susceptible to lysis by healthy donor natural killer (NK) cells at baseline, and cytotoxicity is enhanced by IFNγ-mediated PD-L1 upregulation and ligand targeting with N-601 through an ADCC-dependent mechanism. A. SNUC cell lines were used as targets for healthy donor NK cells versus non-treated (NT) controls. B. N-601 enhances NK cell killing of SNUC cells through antibody-dependent cellular cytotoxicity ADCC. N-601-mediated ADCC assays were performed by co-incubating SNUC cells with N-601 or isotype control antibody (Isotype Ab) prior to exposure to healthy donor NK cells (left). NK cells were treated with anti-CD-16 antibody for ADCC blocking experiments where indicated (right). C. IFNγ-treated SNUC cells show increased sensitivity to NK-cell lysis via N-601-mediated ADCC. SNUC cells were treated with 20 ng/mL of IFNγ or untreated as controls for 24 h prior to co-culture with N-601 or isotype control antibody (Isotype Ab). SNUC cells were used as targets for healthy donor NK cells in ¹¹¹In-release killing assays. NK cells were treated with anti-CD-16 antibody for ADCC blocking experiments where indicated. E:T ratios are 10:1. **P ≤ 0.01, ***P ≤ 0.001.