Figure 2.

CTL epitopes encoded by rAd were processed and presented to tumor-specific CTL. B6 MEC were left uninfected or were infected with rAd-1 harboring minigene 1, rAd-2, harboring minigene 2, or the galactosidase gene (rAdV-LAC-Z). After 48 hr, the infected MEC were tested for the expression of the CTL epitopes in their ability to cause TNF release by the relevant CTL. The presence of TNF in the culture supernatant was measured by the cytotoxic effect on WEHI-164 clone 13 cells. B6 MEC, infected with rAd-1 harboring E1A^234–243-, HPV16 E7^49–57-, and E1B^192–200-derived H-2D^b-restricted CTL epitopes, are able to activate CTL clones specific for these CTL epitopes whereas B6 MEC infected with rAd-2 harboring the E1B^192–200 epitope only activate Ad5E1B-specific CTL. The CTL are not activated upon incubation with uninfected MEC or MEC infected with a control rAd.