ARS | Publication request: Generation and characterization of a LaSota strain recombinant Newcastle disease virus expressing the red fluorescent protein for use in co-infection studies

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 7, 2011
Publication Date: January 26, 2012
Citation: Miller, P.J., Hu, H., Yu, Q., Diel, D.G., Li, J. 2012. Generation and characterization of a LaSota strain recombinant Newcastle disease virus expressing the red fluorescent protein for use in co-infection studies [abstract]. Meeting Abstract. 50:378-387.

Technical Abstract: Newcastle disease virus (NDV) infections result in significant economic losses to poultry producers around the world. The LaSota and B1 vaccine strains of NDV are commonly used to prevent losses from Newcastle disease. Recombination of NDV is thought to occur based on the genomes of NDV isolates that appear to be mixtures of more than one NDV. For recombination to occur, two different NDV isolates must infect the same cell at the same time. Our goal was to assess the ability of two strains of NDV (LaSota and B1) to co-infect chicken cells in vitro. We generated a NDV LaSota strain clone consisting of complementary deoxyribonucleic acid (cDNA), inserted the red fluorescent protein (RFP) gene, and rescued an infectious, recombinant NDV LaSota virus (rLS-RFP) by using reverse genetics approaches. The appearance of RFP in live infected cells confirmed the recovery of rLS-RFP, expressing the reporter gene. The replication kinetics in chicken fibroblast (DF-1) cells and the pathogenicity in eggs and chickens of rLs-RFP did not differ significantly from that of the recombinant LaSota virus without the RFP insert. The recombinants, rLS-RFP and the recombinant B1 with the green fluorescent protein (rB1-GFP), were used to co-infect DF1 cells at different time points. When both viruses were inoculated in DF1 cells at the same time point, a 15% co-infection rate was obtained. Additionally, when the rB1-GFP and the rLS-RFP were inoculated with intervals of 1h, 2h, 3h and 12h between each virus, the co-infection rates were 10%, 9%, 7% and 3%, respectively. These results confirm that different NDV strains can co-infect cell cultures in vitro.