HIV-1 challenge of siRNA transposed GHOST-R3/X4/R5 cells. To determine viral resistance, siRNA transposed transgenic cells were challenged with HIV-1 NL4.3 (CXCR4 tropic virus), HIV-1 BaL (CCR5 tropic virus) or HIV-1 89.6 (dual tropic virus) viruses at an MOI of 0.01. On various days post-infection, cell culture supernatants were collected and analyzed for p24 antigen levels by ELISA to determine the levels of viral inhibition. Untransposed (◆), control RFP transposed (■), CXCR4 siRNA transposed (×) or CCR5 siRNA transposed (○). Panel A – NL4.3, Panel B – BaL, Panel C – 89.6.