Cell Density Plays a Critical Role in Ex Vivo Expansion of T Cells for Adoptive Immunotherapy

Figure 6

Autocrine catalase is the conditioned medium product that protects ATCs from apoptosis. (a) Expression and secretion of catalase by ATCs. Western blot of control medium (lane 1), conditioned medium from ATCs (lane 2), cell lysates of ATCs (lane 3), and catalase control (lane 4) probed with anticatalase antibody. (b) Catalase inhibitor ATZ abrogates the protective effect of conditioned medium from ATCs. ATCs were cultured at high cell density (1×10⁵/mL) (HD) or low cell density (1×10⁴/mL) (LD) in 75 cm² flasks in the presence or absence of 50% conditioned medium from ATCs (CM) and ATZ in 1 or 10 mM for 24 hours. Cell viability was analyzed by flow cytometry.

(a)

(b)