86 GENE THERAPY BY POTENT GENERATION OF SPECIFIC CYTOTOXIC T LYMPHOCYTE AGAINST SPAN-XB/MULTIPLE MYELOMA.

Purpose Multiple myeloma (MM) is difficult to cure by conventional chemotherapeutic modalities but may be amenable to immunotherapeutic approaches. In past studies we have investigated the use of recombinant adeno-associated virus (AAV)-based vectors for their ability to effectively deliver viral antigen and cytokine genes into dendritic cells (DCs). Surprisingly rAAV/viral antigen-pulsing of DC stimulated significant cytotoxic T lymphocytes (CTL) with only one stimulation. Methods Generation of the AAV-Spanxb virus stock, generation and infection of the DC to prime the na•ve T cell and by Facs analysis and Cr (51) to characterized the anti-Span-xb CTL. Summary The generation of CTL against Span-xb antigens represents a more difficult challenge. In this study it is shown that rAAV/Span-xb antigen gene delivery into DC, with 7 days of T cell stimulation, resulted in (1) high MHC class I-restricted, antigen-specific CTL killing of target cells in 51 chromium release assays, (2) high levels of intra-T cell interferon g (IFN-g) expression, and (3) high levels of CD80, CD86, and CD40 expression on DC. Both synthetic, autologous Span-xb-positive targets and primary MM cell lines were good targets for killing by the anti-Span-xb CTL, while Span-xb-negative targets were not significant targets. Conclusion These data suggest that rAAV/antigen gene pulsing of DC is a surprisingly effective technique for generating anti-self-antigen CTL as it is for viral antigens. Furthermore, these data suggest that Span-xb may be an effective antigen for targeting anti-MM CTL in gene therapy.