Cytotoxic effects of mAb4713 on lymphoma/leukemia cell lines.

<p>Cytotoxic effects of mAb4713 on lymphoma/leukemia cell lines.</p

Reactivity and cytotoxic activity of mAb 4713 against lymphoma cell lines.

<p>(A) Flow cytometry analysis of mAb 4713 reactivity analyzed by incubating different lymphoma cell lines with mAb 4713 (4°C; 2 h), followed by Alexa 488-conjugated rat anti-mouse Igs (green histogram). Cytotoxicity was analyzed based on propidium iodide (PI) staining of dead cells (red histogram). (B) Cytotoxic effects of mAb 4713 on IL-2-dependent or IL-2-independent ATL cell lines analyzed by PI staining after incubation with mAb 4713 (37°C; 1 or 2 h). Similar data were obtained in two independent experiments. (C) Kaplan–Meier survival analysis of mAb 4713-treated C.B-17/ICR-SCID mice bearing Raji lymphoma xenografts. The Raji-injected SCID mice (n = 5) were treated with mAb 4713 once (red line) or twice (brown line), or with control IgG once (green line). **p = 0.01 versus isotype control.</p

Mechanism of mAb 4713-induced cell death involving the cytoskeleton.

<p>(A) Impact of chemical inhibitors on the cytotoxic activity of mAb 4713 against L428 and Raji cells. The inhibitors were added 1 or 2 h before the cytotoxicity assay. The percentage of dead cells was determined by trypan blue dye exclusion. **p = 0.01 versus none. ***p = 0.001 versus none. The agents were caspase inhibitors (z-VAD-FMK and z-Asp-DCB), PI-3 kinase inhibitors (wortmannin and LY294002), cytoskeletal inhibitors (cytochalasin D and latrunculin B), necroptosis inhibitor (Necrostatin-1), necrosis inhibitor (IM-54), a cathepsin inhibitor (Cath inib III), and reactive oxygen species scavenger (Tiron). (B) Limiting dilution experiments in which L428 cells were seeded (0.3 cells/well; 96 wells) with 3 μg/ml mAb 4713 or control IgG. After 2 h, the number of live cells per well was counted. **p = 0.01 versus isotype control. ***p = 0.001 versus control IgG. Each value represents the mean ± SD.</p

Microscopy analysis of mAb 4713-induced single cell death shows giant pores.

<p>(A) Light microscopy image showing that the incubation of L428 cells with mAb 4713 caused rapid aggregation and death of single cells after 30 min, as shown by trypan blue exclusion staining. ←, single cell death; ∆, aggregation of cells. Bar: 50 μm (B) Scanning electron microscopy image showing the formation of giant pores on L428 Hodgkin lymphoma cells after a 15 or 30 min incubation with mAb 4713.</p