FIG. 4.

Replication of VSV variants on U87 cells and normal human glia cells. Virus replication was compared for each variant between brain tumor cells and normal human glia cells, using a plaque assay. Monolayers of each culture were infected at an MOI of 1 with the respective VSV variant, and supernatants were collected at the indicated time points. Virus replication was attenuated on human glia cells compared to that on U87 cells, by about 2 log. Also, VSV-p1-GFP and VSV-p1-RFP showed decreased viral replication. Differences between the other variants were marginal. (A) Note the complete block of viral replication after IFN preincubation. (B) In contrast, viral replication in U87 brain tumor cells was higher for each variant and productive even in the presence of IFN. Graphs for replication-restricted VSV-dG variants display the baseline for the original inoculum.