Figure 9

In vitro thymidine kinase (TK) enzyme activity in JAWS II DC transfected with pVR1012-TK. The enzyme activity was measured in the cell lysates using (A) ³H-pencycloviir, a conventional substrate for HSV1-TK enzyme, and (B) ¹⁸F-FIAU. The enzyme expression was confirmed by studying the (C) uptake and retention of ¹⁸F-FIAU in the transfected cells after 4 h of adding the radiolabeled substrate. * p < 0.05 versus nontransfected cells. Results shown here are mean (± SEM) of three experiments.