Autocrine, not paracrine, interferon-gamma gene delivery enhances Ex vivo antigen-specific cytotoxic T lymphocyte stimulation and killing

Abstract

The adoptive transfer of antigen-specific cytotoxic T lymphocytes (CTL) shows promise in the treatment of cancer and infectious diseases. We utilize adeno-associated virus-(AAV-) based antigen gene-loaded dendritic cells (DCs) to stimulate such antigen-specific CTL. Yet further improvements in CTL stimulation and killing may result by gene delivery of various Th1-response interferons/cytokines, such as interferon (IFN- ), as the delivered gene can continuously produce that interferon. However which immune cell type should optimally express IFN- is unclear as the phenotypes of both DC and T cells are enhanced by it. Here, we used AAV to compare and contrast IFN- gene delivery into DC or T cells, and versus the addition of exogenous IFN- , for stimulating carcinoembryonic antigen-(CEA-) specific CTL. It was found that AAV/IFN- delivery into T cells (autocrine) resulted in T cell populations with the highest CD8(+)/CD4(+) ratio, highest IFN- (+)/IL-4(+) ratio, highest CD69(+),CD8(+) levels, and lowest CD4(+)/CD25(+) levels, all consistent with the strongest Th1 response. Most importantly, AAV/IFN- transduction of T cells resulted in antigen-specific T cell populations with the highest killing capabilities, 49 above other treatments. These data strongly suggest that AAV/IFN- autocrine gene delivery into T cells is worthy of further study towards maximizing the generation of antigen-specific anticancer CTL killers. Copyright © 2010 Dazhi Zhang et al.