HC-Ad-induced tumor regression and antiglioma immunological memory, despite active systemic anti-Ad immunity. (a) Illustration depicting the experimental design. Rats peripherally immunized against Ads (Ad0) were implanted with CNS-1 tumors in the brain and treated with 5 × 109 of each HC-Ad (n = 8–14/group), or saline (n = 6–7/group). (b) Kaplan–Meier survival curves show the survival of preimmunized and nonpreimmunized rats. *P < 0.05 vs. saline. Log-rank test. Scatter plot shows the titers of circulating anti-Ad NAB in each group. (c) Kaplan–Meier survival curves show the survival of preimmunized long-term survivors rechallenged in the contralateral striatum of the brain at 1 year after treatment. Naive animals were implanted with CNS-1 cells as controls. *P < 0.05 vs. naive. Log-rank test. DOX, doxycycline; GCV, ganciclovir; HC-Ad, high-capacity adenovirus; NAB, neutralizing antibodies.