EGFP Labelled Respiratory Syncytial Virus

Human respiratory syncytial virus (RSV) is the most important cause of lower respiratory tract disease in infants and young children, and is also the main viral source of respiratory disease in immunosuppressed people and the elderly. Here, researchers constructed a recombinant RSV (rRSV) encoding enhanced green fluorescent protein (EGFP, rRSV-EGFP) and studied its potential for screening anti-RSV drugs. The growth kinetics of rRSV-EGFP were comparable to those of two other recombinant RSVs encoding red fluorescent protein (RFP, rRSV-RFP) or luciferase (Luc, rRSV-Luc), which differed in the sensitivity of screening anti-RSV drugs based on infection of HEp-2 cells. The rRSV encoding EGFP has been successfully constructed and rescued, and has the potential for high-throughput screening of anti-RSV drugs in vitro.

In order to verify the feasibility to select anti-RSV drugs by rRSV-EGFP, the researchers did the test analysis with the known RSV inhibitors including ribavirin and compound P13, as well as two potential anti-RSV compounds of mycophenolic acid and dequalinium chloride. The inhibitory effects of these antiviral drugs on the reduction of replication of rRSV-EGFP, rRSV-RFP, rRSV-Luc or wtRSV Long in HEp-2 cells were compared through qualitative and quantitative analysis. The fluorescence results observed under a fluorescence microscope showed that cells infected with rRSV-EGFP but not rRSV-RFP showed a significant decrease after treatment with all antiviral drugs compared with the mock treatment group (Figures 1a and 1b). As for viral titer determination, the titers of wtRSV Long, rRSV-EGFP, rRSV-RFP, and rRSV-Luc were significantly reduced after treatment with each antiviral drug, but the decrease in rRSV-EGFP was compared with the mock-treated group. most obviously (Figures 1c and 1d). Taken together, these data indicate that, compared with the other two recombinant RSV expressing RFP or Luc, rRSV-EGFP exhibits better sensitivity in RSV inhibitory activity assays for the antivirals tested and at the doses indicated.

Figure 1. The feasibility of screening antiviral agents based on rRSV-infected HEp-2 cells. (Xu M, et al., 2018)