An Ad5[E1-, E2b-]-HER2/neu vector induces immune responses and inhibits HER2/neu expressing tumor progression in Ad5 immune mice.

E S Gabitzsch, Y Xu, S Balcaitis, J P Balint, F R Jones

Etubics Corporation, Seattle, WA 98119, USA. beth@etubics.com

Cancer gene therapy 2011 May

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Immunotherapy is a promising approach for the treatment of cancers. Modified adenovirus 5 (Ad5) vectors have been used as a platform to deliver genes encoding tumor associated antigens (TAA). A major obstacle to Ad5 vector immunotherapy has been the induction of vector immunity following administration or the presence of pre-existing Ad5 immunity, which results in vector mitigation. It has been reported by us that the Ad5[E1-, E2b-] platform with unique deletions in the E1, E2b and E3 regions can induce potent cell mediated immunity (CMI) against delivered transgene products in the presence of pre-existing Ad5 immunity. Here we report the use of an Ad5[E1-, E2b-] vector platform expressing the TAA HER2/neu as a breast cancer immunotherapeutic agent. Ad5[E1-, E2b-]-HER2/neu induced potent CMI against HER2/neu in Ad5 naïve and Ad5 immune mice. Humoral responses were also induced and antibodies could lyse HER2/neu expressing tumor cells in the presence of complement in vitro. Ad5[E1-, E2b-]-HER2/neu prevented establishment of HER2/neu-expressing tumors and significantly inhibited progression of established tumors in Ad5 naïve and Ad5 immune murine models. These data demonstrate that in vivo delivery of Ad5[E1-, E2b-]-HER2/neu can induce anti-TAA immunity and inhibit progression of HER2/neu expressing cancers. © 2011 Nature America, Inc.

Citation

E S Gabitzsch, Y Xu, S Balcaitis, J P Balint, F R Jones. An Ad5[E1-, E2b-]-HER2/neu vector induces immune responses and inhibits HER2/neu expressing tumor progression in Ad5 immune mice. Cancer gene therapy. 2011 May;18(5):326-35