Gene therapy of disseminated malignancy is limited by a lack of targeted vectors that can cross multiple tissue boundaries to reach all tumor deposits. Specific CTLs, however, can be generated against tumor antigens, and are able to cross tissue barriers and to specifically recognize tumor cells. We wish to combine the mobility and targeting functions of T cells with the capacity of adenovirus to efficiently transduce tumor cells and deliver oncolytic genes. As our model we will use CTL targeted to Epstein Barr Virus (EBV), since this virus contributes both to Hodgkin Disease and to immunoblastic lymphomas in the immunocompromised host. We have already infected EBV specific-CTLs with a Moloney derived retrovirus containing the adenovirus E1 gene under CD40L promoter control. This promoter is strictly regulated by T cell activation. When transduced with a therapeutic E1 deleted-Ad5F35 vector, E1-modified EBV specific-CTL produce an active adenovector only following specific engagement of their antigen specific receptors by EBV infected lymphoma cells. The CTL thereby deliver vector directly to tumor cells. In this application, we will test the hypothesis that the EBV-CTLs will traffic to the site of the EBV tumor, will express E1A upon antigen-mediated activation, replicate the adenovector they contain and infect adjacent tumor cells. In three specific Aims we will: 1) optimize the individual components of this system to obtain the largest adenoviral """"""""burst"""""""" size consistent with retention of antigen specific regulation 2) Compare the oncolytic activity of an Ad5F35 thymidine kinase (Tk) vector and a conditionally replication competent vector made by the EBV-CTL """"""""producer"""""""" cells 3) Determine the anti-tumor effects of """"""""producer"""""""" EBV-CTL in a NOD/SCID mouse model of EBV-positive lymphoma. At the conclusion of this study we will have in place an approach that could be implemented to allow truly targeted delivery of therapeutic vectors to disseminated malignancies.
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| Yotnda, P; Zompeta, C; Heslop, H E et al. (2004) Comparison of the efficiency of transduction of leukemic cells by fiber-modified adenoviruses. Hum Gene Ther 15:1229-42 |
