SHORT PAPER Poly I:C Delivery into J774.1 & RAW264.7 Macrophages Induces Rapid Cell Death

Background: Cytosolic double-stranded RNA (dsRNA) is an important ‘molecular signature’ for the detection of intracellular viral infections. Although intracellular dsRNA is a known potent inducer of apoptosis, the optimal time and dose for the onset of dsRNA-mediated apoptosis have not been studied in detail. Objective: To perform an accurate temporal assessment of the cell death responses in dsRNA-dependent cytotoxicity. Methods: Poly I:C (PIC), a synthetic dsRNA molecule was delivered intracellularly into J774.1 and RAW264.7 murine macrophages via electroporation. Cell viability was measured using the MTT assay and apoptosis was determined by sub- G0/G1 DNA content using flow cytometry. Results: Loss of cell viability was seen as early as 3h post-electroporation of macrophages. A significant increase in the sub- G0/G1 DNA content consistent with apoptosis was observed in PIC-electroporated macrophages as early as 3h post electroporation. Conclusion: Intracellular PIC delivery induces rapid macrophage cell death.