FIG. 5.

Infection of PBMC with virus from immortalized cells. ACH-immortalized cells were exposed to gamma radiation and cocultured with uninfected activated PBMC. Relative cellular proliferation was monitored every 7 to 14 days by MTT conversion assay with 100-μL aliquots of the cultures and was adjusted for the number of culture passages. Whereas the irradiated cells alone do not proliferate (data not shown) and the PBMC alone (Δ) proliferated transiently, the cocultured cells proliferated indefinitely. Cells were immortalized with ACH.wt (⧫), ACH.p12^I (•), ACH.p12^I/p30^II (×), or ACH.p30^II (□).