Replication Assay. Cells were infected with a MOI of 2 and allowed to incubate for 48 hours at 37°C with 5% CO2. Samples were taken every four hours and viral titers were determined by plaque assay. The replication curve of MNV-1 in both the BV-2 and RAW 264.7 cell lines was then plotted. Results are showing similar growth and viral titer production in both cell lines, among all time points.