1. Tumour cells dying under phox‐ER stress conditions induce DC maturation and activate the adaptive immune system.
Tumour cells dying under phox‐ER stress conditions induce DC maturation and activate the adaptive immune system. (A) In‐vitro phagocytosis of T24 cells treated with Hyp‐PDT (red) by human immature dendritic cells (hu‐iDCs) (green). The confocal fluorescence images show various phagocytic interactions between dying T24 cells and hu‐iDCs, such as tethering (a), initiation of engulfment by extending the pseudopodia (b), and final stages of engulfment (c); scale bar=20 μm. (B) Human DC maturation analysis. T24 cells were left untreated (CNTR), freeze/thawed (accidental necrosis=AN), or treated with a high PDT dose. They were then co‐incubated with hu‐iDCs. As a positive control, hu‐iDCs were stimulated with LPS for 24 h. After co‐incubation, the cells were immunostained in two separate groups for CD80/CD83 positivity and CD86/HLA‐DR positivity and scored by FACS analysis. Data have been normalized to the ‘CNTR T24 + hu‐iDCs’ values. Fold change values are means of two independent experiments (two replicate determinations in each)±s.e.m. (*P<0.05, versus ‘CNTR T24+hu‐iDCs’). (C, D) Cytokine and respiratory burst patterns exhibited by human DCs. The T24‐hu‐iDC co‐incubation conditioned media obtained during the experiments detailed in (B) were recuperated followed by analysis for concentrations of nitrite (solubilized form of nitric oxide or NO) (C), and IL‐10 (D). Absolute concentrations are the means of two independent experiments (four replicate determinations in each)±s.d. (*P<0.05 versus hu‐iDC only). (E) Priming of adaptive immune system by dead/dying CT26 cells. Following immunization with PBS (CNTR) or with CT26 cells treated with tunicamycin (TUN), mitoxantrone (MTX) and the highest PDT dose, the mice were rechallenged with live CT26 tumour cells. Subsequently, the percentage of mice with tumour‐free rechallenge site was determined (n represents the number of mice).
Abhishek D Garg et al. EMBO J. 2012;31:
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