Figure 7.

Matrilysin-expressing clones demonstrate reduced sensitivity to immune cells. Monolayers of each of the vector control (Vector) or matrilysin-expressing (MAT) clones were incubated for 6 hours with freshly isolated, in vitro activated splenocytes in the presence of 1 µg/ml cycloheximide. The monolayers were then washed extensively to remove the spleen cells and the clones were further incubated for 16 hours, again in the presence of cycloheximide. The cells were harvested, stained with propidium iodide and the extent of apoptosis (subG1 DNA) determined by flow cytometry. Results shown are mean and SEM from three separate experiments. For each cell line, the results obtained for two different vector and two matrilysin-expressing clones were combined. Statistical significance was determined using Student's t test and the results are indicated with asterisks where ** represents P=.0014 and * represents P≤.03.