Neuropathological analysis of brains at 5 days, 30 days, 6 months, and 1 year after intratumoral administration of bicistronic HC-Ad to naïve, tumor-bearing Lewis rats. Images of TK and Flt3L immunoreactivity are higher-magnification images from the brain hemisphere ipsilateral to the HC-Ad injection. TH, tyrosine hydroxylase; MBP, myelin basic protein; MHCII, major histocompatibility complex II.