In some experiments, lymphocytes from tolerized mice were transferred to conditioned recipients to further evaluate the presence of anti-Ova lymphocytes and to study their functionality in vivo. For that, 50 × 10 6 splenocytes harvested from individual mice that have be treated 80 days before with AAV-Ova, with or without immunomodulatory regimens, were injected i.v. into 5 Gy-irradiated syngenic C57BL/6 recipient. One day after, each individual mouse was shaved and injected subcutaneously with 1 × 10 6 syngenic EG7 tumor cells expressing the Ova antigen and known to be sensitive in vivo to CD8 + T cell cytotoxicity in primed animals (Moore et al., 1988) . Tumor sizes were measured with a digital caliper three times a week during 26 days. Tumor volume was calculated as length × width × [(length + width)/2].