Recombinant D7 protein inhibits DENV2 infection in U937 cells.

<p>(A) The Promega CellTox^TM Green Cytotoxicity Assay was used to determine the toxicity of ten-fold dilutions of recombinant D7 protein on U937 cells 24 hours post-treatment. (B) U937 cells were either uninfected (UI), infected with DENV2 alone, pre-treated with 10-fold dilutions of recombinant D7 protein followed by DENV2 infection, or co-treated with 10-fold dilutions of recombinant D7 protein with concomitant DENV2 infection. Total RNA was harvested and qRT-PCR was performed 24 hours post-infection. Relative levels of DENV2 were normalized to B2M. (C) U937 cells were either uninfected (UI), infected with DENV2 alone, or infected followed by post-treatment with 10-fold dilutions of recombinant D7 protein. Post-treatment began 24 hpi and lasted 8 hours. Total RNA was harvested and qRT-PCR was performed 48 hours post-infection. Relative levels of DENV2 were normalized to B2M. (D) U937 cells were either uninfected (UI), infected with DENV2 alone, or pre-treated with recombinant Hig-tagged GFP, representing the highest concentration used for D7 protein followed by DENV2 infection. Total RNA was harvested and qRT-PCR was performed 24 hours post-infection. Relative levels of DENV2 were normalized to B2M. Data represent averages of at least 3 independent experiments. Student’s t tests were performed to assess statistical significance between groups.