Fig 4. ZIKV infection induced apoptosis in macrophages.

PMA-differentiated THP-1 cells were infected with ZIKV and observed under a light microscope at 12 and 24 hrs p.i. for the cells showing apoptotic blebing (arrow) (A). The cells were treated with 10 μM of apoptosis activator 2, a caspase3 activator, for 2 hrs as a positive control. A TUNEL assay was applied to ZIKV-infected THP-1 cells at 12 and 24 hrs p.i. and the TUNEL positive cells were shown (arrow). The cells were treated with 20 U/mL of DNase I for 10 min as a positive control (B).