Journal: Oncoimmunology

Article Title: FTL008.16, a 5T4-Conditional 4-1BB bispecific antibody, potently enhances antitumor immunity via tumor-directed t-cell activation

doi: 10.1080/2162402X.2026.2684136

Figure Lengend Snippet: FTL008.16 exhibits 5T4-dependent immune cell activation and tumor cell killing in PBMC co-cultures. (a) PBMCs were stimulated with anti-CD3 (0, 10, or 100 ng/mL), and 4-1BB expression on CD4 + T, CD8 + T, and NK cells was analyzed in co-culture with CT26 h5T4 or CT26-WT cells. (b) Concentration-dependent binding of FTL008.16 to anti-CD3/CD28-activated T-cell subsets (CD3 + , CD4 + , CD8 + ) was assessed by flow cytometry. (c) CFSE-labeled PBMCs were stimulated with anti-CD3 and serial dilutions of FTL008.16 or hIgG1 isotype control in the presence of CHO h5T4 cells. CD8 + T-cell counts were assessed by flow cytometry at 96 hours. (d) IFN- γ release from PBMCs and purified T cells was measured after co-culture with 5T4-expressing tumor cells and treatment with FTL008.16 or FTL001 control. (e) Purified T cells and mitomycin C-treated CT26-WT or CT26 h5T4 tumor cells were incubated with serial dilutions of FTL008.16. IFN- γ secretion in supernatants was measured by ELISA. (f) FTL008.16 does not induce cytokine release from PBMCs of healthy donors ( n = 3), as assessed by cytometric bead array (CBA). (g) PBMC-mediated cytotoxicity of FTL001 and FTL008.16 against 5T4-positive (DLD-1) and 5T4-negative (HEK 293T) cells. **p < 0.01, ***p < 0.001 vs. hIgG1 control.

Article Snippet: Human PBMCs were labeled with CFSE (MCE, #HY-D0938) according to the manufacturer’s instructions.

Techniques: Activation Assay, Expressing, Co-Culture Assay, Concentration Assay, Binding Assay, Flow Cytometry, Labeling, Control, Purification, Incubation, Enzyme-linked Immunosorbent Assay