Figure 4.

NS2B3 of ZIKV inhibits apoptotic cell death. (a) HT1080 cells were infected with ZIKV (MOI=10). Trypan blue-positive dead cells were counted. (b) Immunoassay of extracts of HT1080 cells transfected with poly (I:C) (5 μg ml⁻¹) for 6 h along with or without ZIKV pre-infection for 48 h. The c-PARP, c-Caspase 3 (c-Cas3) and β-actin were quantified and the relative ratios were calculated. (c) Immunoassay of extracts of HT1080 cells transfected with HA-NS1, HA-NS2B3 or HA-NS4B followed by cytoplasmic poly (I:C) (5 μg ml⁻¹) treatment for 6 h. (d) HT1080 cells transfected with empty vector (EV) or HA-NS2B3 were treated with cytoplasmic poly (I:C) (5 μg ml⁻¹) for 12 h. Trypan blue-positive dead cells were counted (right) and photographed (left). (e) Fluorescence-activated cell sorting analysis of Annexin V and propidium iodide (PI) staining in HT1080 cells transfected with empty vector (EV) or HA-NS2B3 followed by poly (I:C) (5 μg ml⁻¹) treatment for 12 h (left). The ratios of Annexin V-negative and PI-negative (Annexin V−/PI−), Annexin V-positive and PI-negative (Annexin V+/PI−), Annexin V-positive and PI-positive (Annexin V+/PI+), and Annexin V-negative and PI-positive (Annexin V−/PI+) cells were analyzed (right). Data in a, b and d are expressed as means±s.d. of at least two independent experiments. **P<0.01. NS, not significant.