Differential immune-modulatory effect of didemnin B against different myeloma, leukemia, and lymphoma cell lines. PBMCs were isolated from a healthy donor and stimulated with IL-2 (10 ng/mL) for 24 hours. PBMCs were then cultured at increasing effector-to-target ratios for 4 hours in the presence or absence of didemnin B with the luc⁺ myeloma lines MM.1S (A), RPMI8226 (B), KMS34 (C), and Dox40 (D); the luc⁺ lymphoma lines HT (E) OCILY1 (F) Farage (G); and the leukemia line KU812F (H). Tumor cell viability was quantified by CS-BLI. Data were normalized to each respective drug- and PBMC-free culture of MM.1S cells (n = 4 for each condition).