Figure 3.

GBex induced apoptosis of primary CD8+ T cells and reduced cytokine expression. (A) Cell viability: CD8⁺ Jurkat cells were co-incubated for 24 h with increasing protein levels of GBex isolated from supernatants of the U251 GB cell line. (B) Annexin V-stained primary human-activated CD8⁺ T cells incubated with GBex or PBS as a control for 24 h. (C) Cell viability of CD8⁺ Jurkat cells preincubated with anti-FAS Mab and after 1 h with 4.2 µg of GBex protein isolated from supernatants of the U251 GB cell line. *Significantly different from control cells and ^&different from FAS-isotype control (CTRL). (D) Expression levels of IL-2, CCL3, TNF-α, and INF-γ measured by flow cytometry in CD8⁺ Jurkat cells co-incubated with GBex. Data were analyzed by ANOVA followed by post hoc comparisons (Tukey test). *Significantly different from control cells at P < .005 and ^&Significantly different from isotype CTRL.