Development of DC-vaccine against tuberclulosis

开发有效的细胞内病原体疫苗策略是当前医学研究的主要前沿之一。由于树突状细胞（dc）是最有效的抗原呈递细胞，启动初级免疫反应，它们可能提供对细胞内病原体的保护性免疫的重要组成部分。在本研究中，我们试图开发一种针对兼性细胞内病原体单核增生李斯特菌（Listeria monocytogenes, Lm）的转基因dc疫苗。进一步，我们确定了基因修饰DC疫苗的有效性，并将其与DNA疫苗进行了比较。小鼠骨髓源性dc用编码溶血素O (LLO) 91-99的cDNA逆转录转导，LLO是一种由Lm产生的溶血素，是抗李斯特菌免疫的H-2K^d限制性靶免疫优势表位。通过静脉注射转导的dc免疫BALB/c小鼠。采用基因枪皮下注射编码llo91 -99的质粒进行DNA免疫。我们发现，专门设计表达LLO 91-99的DC疫苗可以有效地产生肽特异性CD8+ T细胞，表现出很强的细胞毒活性和IFN-γ的产生，从而诱导对Lm的有效保护性免疫。此外，基于dc的疫苗在诱导抗李斯特菌免疫方面比DNA疫苗更有效。这些数据表明，表达单一免疫显性表位的基因修饰DC疫苗可用于细胞内病原体感染，并且可能优于DNA疫苗，为针对细胞内病原体的疫苗设计提供了另一种策略。

The development of effective vaccine strategies for intracellular pathogens is one of major frontiers of current medical research. As dendritic cells (DCs) are the most potent antigen-presenting cells that initiate the primary immune response, they may provide an essential component of protective immunity against intracellular pathogens. In the present study, we attempted to develop genetically modified DC-based vaccine against Listeria monocytogenes (Lm), a facultative intracellular pathogen. Further, we determined the efficacy of the gene modified DC vaccine and also compared it with that of DNA vaccine. Murine bone marrow-derived DCs were retrovirally transduced with cDNA encoding lysteriolysin O (LLO) 91-99, a hemolysin produced by Lm, that is a H-2K^d-restricted target immunodominant epitope of antilisterial immunity. Naive BALB/c mice were immunized by intravenous injection of the transduced DCs. For DNA immunizaton, plasmid encoding LLO 91-99 was subcutaneouly injected using a gene gun. We found that specifically designed DC vaccine to express LLO 91-99 could effectively generate peptide-specific CD8+ T cells exhibiting strong cytotoxic activity and IFN-γ production, leading to induction of potent protective immunity against Lm. Furthermore, the DC-based vaccine was more effective than the DNA vaccine at eliciting anti-listerial immunity. These data suggest that gene modified DC vaccine expressing a single immunodominant epitope is useful for intracellular pathogen infection and may be superior to DNA vaccine, providing an alternative strategy for vaccine design against intracellular pathogens.