A DNA vaccine co-expressing antigen and an anti-apoptotic molecule further enhances the antigen-specific CD8+ T-cell immune response.

We have shown that DNA encoding the anti-apoptotic protein Bcl-xL enhances E7-specific CD8+ T-cell responses and DNA encoding pro-apoptotic protein caspase-3 suppresses E7-specific CD8+ T-cell responses when co-administered intradermally via gene gun with DNA encoding human papillomavirus type 16 (HPV-16) E7 linked to the sorting signal of the lysosome-associated membrane protein type 1 (LAMP-1). E7 and LAMP-1 are linked to form the chimeric Sig/E7/LAMP-1 (SEL). Because co-administration does not ensure delivery of both constructs to a single cell, we used pVITRO, a mammalian expression vector with double promoters, to ensure expression of both molecules in the same cell. We vaccinated C57BL/6 mice with pVITRO-SEL-Bcl-xL, pVITRO-SEL-mtBcl-xL, pVITRO-SEL, or pVITRO-SEL-caspase-3 intradermally via gene gun and intramuscularly via injection. We demonstrated that vaccination with pVITRO achieved similar results to a co-administration strategy: that Bcl-xL enhanced the E7-specific CTL response and caspase-3 suppressed the E7-specific CTL response. In addition, we found intradermal vaccination elicited significantly higher numbers of E7-specific CD8+ T cells compared to intramuscular vaccination. Thus, intradermal vaccination with a pVITRO vector combining an anti-apoptotic strategy (Bcl-xL) and an intracellular targeting strategy (SEL) further enhances the E7-specific CD8+ T-cell response and guarantees co-expression of both encoded molecules in transfected cells.

Kim TW ，Hung CF ，Zheng M ，Boyd DA ，He L ，Pai SI ，Wu TC ... -  《JOURNAL OF BIOMEDICAL SCIENCE》

Enhancing DNA vaccine potency by combining a strategy to prolong dendritic cell life with intracellular targeting strategies.

Kim TW ，Hung CF ，Boyd D ，Juang J ，He L ，Kim JW ，Hardwick JM ，Wu TC ... -  《JOURNAL OF IMMUNOLOGY》

DNA vaccines employing intracellular targeting strategies and a strategy to prolong dendritic cell life generate a higher number of CD8+ memory T cells and better long-term antitumor effects compared with a DNA prime-vaccinia boost regimen.

Kim TW ，Lee JH ，He L ，Boyd DA ，Hung CF ，Wu TC ... -  《HUMAN GENE THERAPY》

Targeting human papillomavirus type 16 E7 to the endosomal/lysosomal compartment enhances the antitumor immunity of DNA vaccines against murine human papillomavirus type 16 E7-expressing tumors.

:DNA vaccination is an attractive approach for tumor immunotherapy because of its stability and simplicity of delivery. Advances demonstrate that helper T cell responses play a critical role in initiating immune responses. The aim of the current study is to test whether targeting HPV-16 E7 to the endosomal/lysosomal compartment can enhance the potency of DNA vaccines. We linked the lysosome-associated membrane protein 1 (LAMP-1) to HPV-E7 to construct a chimeric DNA, Sig/E7/LAMP-1 DNA. For in vivo tumor prevention experiments, mice were vaccinated with E7 DNA or Sig/E7/LAMP-1 DNA via gene gun, followed by tumor challenge. For in vivo tumor regression experiments, mice were first challenged with tumor cells and then vaccinated with E7-DNA or Sig/E7/LAMP-1 DNA. Intracellular cytokine staining with flow cytometry analysis, cytotoxic T lymphocyte (CTL) assays, enzyme-linked immunoabsorbent assay (ELISA), and enzyme-linked immunospot (ELISPOT) assays were used for in vitro E7-specific immunological studies. In both tumor prevention and tumor regression assays, Sig/E7/LAMP-1 DNA generated greater antitumor immunity than did wild-type E7 DNA. In addition, mice vaccinated with Sig/E7/LAMP-1 DNA had greater numbers of E7-specific CD4+ helper T cells, higher E7-specific CTL activity, and greater numbers of CD8+ T cell precursors than did mice vaccinated with Sig/E7 or wild-type E7 DNA. Sig/E7 generated a stronger E7-specific antibody response than did Sig/E7/LAMP-1 or wild-type E7 DNA. Our results indicate that linkage of the antigen gene to an endosomal/lysosomal targeting signal may greatly enhance the potency of DNA vaccines.

Ji H ，Wang TL ，Chen CH ，Pai SI ，Hung CF ，Lin KY ，Kurman RJ ，Pardoll DM ，Wu TC ... -  《HUMAN GENE THERAPY》

Enhancement of sindbis virus self-replicating RNA vaccine potency by targeting antigen to endosomal/lysosomal compartments.

Cheng WF ，Hung CF ，Hsu KF ，Chai CY ，He L ，Ling M ，Slater LA ，Roden RB ，Wu TC ... -  《HUMAN GENE THERAPY》