Highly Active Microbial Phosphoantigen Induces Rapid yet Sustained MEK/Erk- and PI-3K/Akt-Mediated Signal Transduction in Anti-Tumor Human γδ T-Cells
Figure 6
Leukemia cell killing by HMB-PP-activated γδ T-cells.
(A) In vitro lysis of Molt-4 leukemia cells. MACS-sorted γδ PBL (of which 85–95% Vγ9+) were pre-activated for 72 hours with 1 or 10 µg/ml αCD3 mAb (OKT3), or 1 or 10 nM HMB-PP in the absence of IL-2, and also combined at the lower concentrations with IL-2 (100 U/ml). For the killing assay, DDAO-SE-labelled Molt-4 cells and pre-activated γδ PBL were co-incubated for 3 hours in media devoid of activating compounds. Samples were then stained with Annexin V to identify dying (Annevin V+) tumor (DDAO-SE+) cells by flow cytometry. (B) Data summary for killing assays (as in A) performed with three distinct leukemia cell lines. (C–D) Bioluminescent imaging of NOD/SCID mice inoculated with luciferase+ Molt-4 leukemic cells, with (D) or without (C) co-injection of pre-activated γδ PBL, analyzed weekly as described in Materials and Methods. (E) LivingImage quantification of photon signals (tumor load) collected at day 28 of the experiment illustrated in (C–D). Comparison of γδ-treated and control animals (n = 5, p<0.05). Data in this figure are representative of 3 (A–B) or 2 (C–E) independent experiments.
doi: https://doi.org/10.1371/journal.pone.0005657.g006