Ad(CEA)â¢CFm40L mice intravenously with Lewis Lung carcinoma cells that were engineered to ... Chien-fu Hung,1 Taewoo Kim,1 T. C. Wu.1. 1Pathology, Johns ...
CANCER IMMUNOTHERAPY Ad(CEA)•CFm40L mice intravenously with Lewis Lung carcinoma cells that were engineered to express CEA (LLC-CEA) and LLC cells alone, twenty-eight days following the second immunization. The lung metastases that occurred in the naïve and the mice immunized with untargeted Ad(CEA) at all three doses examined were completely abrogated in the mice that were immunized with Ad(CEA)•CFm40L at 1010vp and 108vp doses. Although high antibody titer had no bearing on tumor protection, a strong correlation was observed between reduced lung metastasis and enhanced antiCEA T-cell responses. In order to determine if targeted delivery of Ad(CEA) can break self-tolerance against CEA-bearing tumors, we are continuing this experiment in CEA-transgenic mice.
268. Enhancement of DNA Vaccine Potency by Coadministration of a Tumor Antigen Gene and DNA Encoding Serine Protease Inhibitor-6 Chien-fu Hung,1 Taewoo Kim,1 T. C. Wu.1 1 Pathology, Johns Hopkins University, Baltimore, MD. Serine protease inhibitor 6 (SPI-6), also called Serpinb9, inhibits granzyme B and thus may provide a method for delaying apoptotic cell death in dendritic cells. We have previously enhanced DNA vaccine potency by targeting antigen to MHC antigen presentation pathways, using proteins such as Mycobacterium tuberculosis heat shock protein 70, calreticulin, domain II of Pseudomonas aeruginosa exotoxin A, or the sorting signal of the lysosome-associated membrane protein type 1. In this study, we explored intradermal coadministration of DNA encoding SPI-6 with DNA constructs encoding human papillomavirus type 16 E7 linked to these intracellular targeting molecules for its ability to generate E7-specific CD8+ T-cell immune responses and E7-specific antitumor effects. This combination of strategies resulted in significantly increased E7-specific CD8+ T-cell and CD4+ Th1-cell responses, enhanced tumor treatment ability, and stronger tumor protection when compared with vaccination without SPI-6. Among these targeting strategies tested, mice vaccinated with Sig/E7/lysosome-associated membrane protein type 1 mixed with SPI-6 showed the greatest fold increase in E7-specific CD8+ T cells ( approximately 5-fold). Vaccination with a nonfunctional mutant of SPI-6 did not result in immune enhancement, indicating that enhancement was dependent on the antiapoptotic function of SPI-6. Our results suggest that DNA vaccines combining strategies that enhance MHC class I and II antigen processing with SPI-6 have potential clinical implications for control of viral infection and neoplasia.
269. Targeting Self Antigens through Allogeneic TCR Gene Transfer Moniek de Witte,1 Miriam Coccoris,1 Monika C. Wolkers,1 Marly van den Boom,1 Helmut W. Kessels,1 Ton N. Schumacher. 1 Division of Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands. Adoptive therapy with allogeneic or tumor-specific T cells has shown substantial clinical effects for several human tumors, but the widespread application of this strategy remains a daunting task. As an alternative to the adoptive transfer of T cells, we and others have examined the feasibility of transfer of T cell receptor genes into recipient T cells. The antigen-specificity of T lymphocytes is solely determined by the T cell receptor (TCR) α and β chains. Consequently, genetic transfer of TCR chains may form an appealing strategy to impose a desirable tumor-antigen specificity onto cytotoxic or helper T cell populations. In this strategy, autologous or donor-derived T cell populations are equipped with a TCR of defined reactivity in short-term ex vivo cultures, and re-infusion of the redirected cells is used to supply T cell reactivity against defined tumor-specific antigens. Molecular Therapy Volume 9, Supplement 1, May 2004 Copyright © The American Society of Gene Therapy
We have previously described the genetic introduction of an antigen-specific T cell receptor into peripheral T cells in a mouse model system1 . These experiments reveal that T cells that are redirected by TCR gene transfer expand dramatically upon in vivo antigen encounter and efficiently home to effector sites. While these data demonstrated that redirected T cells can function in vivo, two issues that are essential for the application of this strategy in the human setting2 remained unaddressed: - Can redirected T cells function in an allogeneic, partially MHCmismatched setting? - Can redirected T cells be used to target specific tissues in settings where the endogenous T cell repertoire fails due to self-tolerance? We have now addressed these two issues in murine model systems. Collectively, these data suggest that redirection of T cells by TCR gene therapy forms a viable new strategy for the rapid induction of tumor-specific immunity. 1 H.W. Kessels et al. Nat. Immunol. 2: 957-961 (2001). 2 T.N. Schumacher. Nat. Rev. Immunol. 2: 512-519 (2002).
270. Treatment of CT26 Tumors with Dendritic Cells Transduced with a Recombinant SV40 Vector Expressing Interleukine 15 Maria Vera,1 Gloria G. Aseguinolaza,1 Nerea Razquin,1 Ignacio Melero,1 Jesus Prieto,1 Puri Fortes.1 1 Hepatology and Gene Therapy, FIMA. University of Navarra, Pamplona, Navarra, Spain. Tumors can be treated with cytokines that activate the immunoresponse against tumor cells. Viral vectors have been used to direct cytokine expression to the tumor and surrounding tissues or to cells like dendritic cells (DCs). We decided to study the efficiency of recombinant vectors based on Simian Virus 40 virus (SV40) to deliver interleukine 12 (IL12) or interleukine 15 (IL15) to the tumor or to transduced DCs. We produced recombinant viruses expressing firefly luciferase (rSVLuc), murine IL12 (rSVIL12) and murine IL15 (rSVIL15). Expression, secretion and activity of recombinant SV40 expressed IL12 and IL15, was demonstrated by several means. Infection of the tumour cell line CT26 and of human DCs by rSVIL12 was determined by Elisaagainst murine IL12. In vitro pre-treatment of CT26 cells with rSVLuc, rSVIL12 or rSVIL15 before subcutaneous inoculation in BALB/C mice did not prevent tumor formation. Intratumoral treatment of CT26 subcutaneous tumours with rSVLuc, rSVIL12 or rSVIL15 had no effect in tumor growth, even when three intratumoral viral injections were performed. We also used these vectors to infect in vitro differentiated BALB/C mice DCs obtained from bone marrow . Infection of immature DCs with rSV40 vectors did not change the expression of cell surface markers CD80, CD86, CD11c, CD40, HLA-I and HLA-II, indicating that DCs tranduced by rSV40 vectors maintained immature after virus infection. We assayed the antitumoral efficiency of infected and maturated DCs injected intratumoraly or infected immature DCs injected intratumoraly or intravenously. The best result was obtained with immature DCs injected directly inside the tumor. 73% tumour remissions were obtained with DCs expressing IL15 and 40% remissions with DCs transduced by rSVIL12. An elispot and a cytotoxic assay indicated that mice treated with DCs expressing IL15 had the highest amount of INFg producing T cells and cytotoxic T cells. These results can be explained by the ability of IL15 to enhance the interaction between DCs and T cells. We conclude that DCs infected with rSVIL15 vectors could be a good alternative to activate the immuno-response against tumor cells.
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