FIG. 5.

In vitro and in vivo transgene expression from armed MAV-1. For in vitro transgene expression (A), 3T6 and Pan02 cells were infected with DLFM or DMFL at an MOI of 5 PFU/cell in duplicate, the supernatants were collected at 72 h postinfection, and GM-CSF levels (mean ± the standard error of the mean) were determined by ELISA. (B) For the DLFM vector, infection of Pan02 cells was performed in the presence (dotted line) or absence (solid line) of 20 μg/ml AraC, a DNA replication inhibitor, to determine if transgene expression occurred in the absence of viral DNA replication. For in vivo transgene expression, female C57BL/6 mice bearing subcutaneous Pan02 tumors (n = 5 per group) were injected i.t. with a single dose (1 × 10⁷ PFU in a 50-μl volume) of dlE102 (C) or DLFM (D). The tumors were harvested at 1, 2, 3, 7, and 11 days posttreatment, and the i.t. level of mGM-CSF was determined by ELISA and normalized to tumor size by determining the total protein content of the tumor homogenate. The data are presented as milligrams of mGM-CSF per milligram of total protein for individual animals at the various time points.