Uninfected PBMCs
The PBMCs from healthy volunteer's blood  were seeded in 100-mm dishes at 1  10^7 cells/dish and then  incubated with the fresh DMEM medium for 12 hours. And then cells were cross-linked with 1% formaldehyde for 10 minutes at room temperature, and quenched for 5 minutes with 0.125 M glycine. Afterward, cells were collected and lysed in 1% SDS lysis buffer supplemented with protease inhibitors cocktail, sonicated with a 1/8-inch probe (5 seconds on/10 seconds off, 30 cycles, 25% of maxi power) by sonicator (Branson 550) to obtain genomic DNA fragments with an average size of 150500 bp. ChIP was performed following the protocol provided by Millipore ChIP Assay kit (Millipore, Cat# 17-409) according to the manufacturers introduction.