Slifka M K, Shen H, Matloubian M, Jensen E R, Miller J F, Ahmed R
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
J Virol. 1996 May;70(5):2902-10. doi: 10.1128/JVI.70.5.2902-2910.1996.
Listeria monocytogenes is a facultative intracellular bacterium that is able to escape phagocytic vesicles and replicate in the cytoplasm of infected cells. As with viral vectors, this intracytoplasmic life cycle provides a means for introducing foreign proteins into the major histocompatibility complex class I pathway of antigen presentation. Using recombinant L. monocytogenes (rLM) strains expressing the full-length nucleoprotein (NP) or a single cytotoxic T-lymphocyte (CTL) epitope from lymphocytic choriomeningitis virus (LCMV), we analyzed antiviral CTL responses induced by rLM vaccination. After vaccination, rLM was cleared from the host within 7 days while inducing an LCMV-specific ex vivo CD8+ effector CTL response. Virus-specific CTL memory was maintained for 6 months postvaccination, as demonstrated by vigorous secondary CTL responses after in vitro stimulation. A single immunization with rLM that expressed either the full-length NP gene or the CTL epitope alone resulted in LCMV NP-specific CTL precursor frequencies of approximately 1/10(4) CD8+ T cells. A second rLM vaccination resulted in enhanced virus-specific CTL activity and in vitro proliferation. rLM-vaccinated mice were protected against chronic viral infection by an accelerated virus-specific memory CTL response. These mice cleared infectious virus as well as viral antigen, suggesting that sterilizing immunity was achieved. In contrast to mice that received wild-type LM, rLM-vaccinated mice were protected from virally induced immunosuppression and splenic atrophy associated with chronic LCMV infection. The ability to elicit long-term cell-mediated immunity is fundamental in designing vaccines against intracellular pathogens, and these results demonstrate the efficacy of recombinant LM vaccination for inducing protective antiviral CTL memory.
单核细胞增生李斯特菌是一种兼性胞内细菌，能够逃离吞噬小泡并在受感染细胞的细胞质中复制。与病毒载体一样，这种胞质内生命周期为将外源蛋白引入主要组织相容性复合体I类抗原呈递途径提供了一种手段。我们使用表达淋巴细胞脉络丛脑膜炎病毒（LCMV）全长核蛋白（NP）或单个细胞毒性T淋巴细胞（CTL）表位的重组单核细胞增生李斯特菌（rLM）菌株，分析了rLM疫苗接种诱导的抗病毒CTL反应。疫苗接种后，rLM在7天内从宿主体内清除，同时诱导LCMV特异性的体外CD8 +效应CTL反应。疫苗接种后6个月仍维持病毒特异性CTL记忆，体外刺激后的强烈二次CTL反应证明了这一点。单独表达全长NP基因或CTL表位的rLM单次免疫导致LCMV NP特异性CTL前体频率约为1/10(4) CD8 + T细胞。第二次rLM疫苗接种导致病毒特异性CTL活性增强和体外增殖。rLM疫苗接种的小鼠通过加速的病毒特异性记忆CTL反应免受慢性病毒感染。这些小鼠清除了感染性病毒以及病毒抗原，表明实现了无菌免疫。与接受野生型LM的小鼠相比，rLM疫苗接种的小鼠免受病毒诱导的免疫抑制和与慢性LCMV感染相关的脾萎缩。引发长期细胞介导免疫的能力是设计针对细胞内病原体疫苗的基础，这些结果证明了重组LM疫苗接种诱导保护性抗病毒CTL记忆的功效。
