Glucuronidase activity as an indicator of cell death and rVACV titer.

<p><b>A)</b> The activities of lactate dehydrogenase and GusA (orange) or GusPlus (blue) in the supernatant of infected A549 (top panel), PC-3 (middle) and CV-1 (lower panel) cells correlated well (R²>0.8), which indicates that glucuronidase can be used as an indicator of (virus mediated) cell lysis. <b>B)</b> Due to its higher specific activity, GusPlus resulted in higher fluorescent product signal when compared to GusA specific signals in the same cells at the same time post infection. At the same time, the plaque forming units or glucuronidase ratios were similar (ratio about 1) in GLV-1h68 or GLV-1h408 infected cells. Data represent the average plus standard deviation of GLV-1h408/GLV-1h68-ratios obtained from simultaneously infected cells at different times post infection (n = 15). Asterisks indicate statistical differences (p<0.005) between fluorescence ratios and pfu- or glucuronidase ratios.