Place David E, Williamson David R, Yuzefpolskiy Yevgeniy, Katkere Bhuvana, Sarkar Surojit, Kalia Vandana, Kirimanjeswara Girish S
Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, Pennsylvania, United States of America.
PLoS One. 2017 Dec 28;12(12):e0190384. doi: 10.1371/journal.pone.0190384. eCollection 2017.
Progress towards a safe and effective vaccine for the prevention of tularemia has been hindered by a lack of knowledge regarding the correlates of protective adaptive immunity and a lack of tools to generate this knowledge. CD8+ T cells are essential for protective immunity against virulent strains of Francisella tularensis, but to-date, it has not been possible to study these cells in an antigen-specific manner. Here, we report the development of a tool for expression of the model antigen ovalbumin (OVA) in F. tularensis, which allows for the study of CD8+ T cell responses to the bacterium. We demonstrate that in response to intranasal infection with the F. tularensis Live Vaccine Strain, adoptively transferred OVA-specific CD8+ T cells expand after the first week and produce IFN-γ but not IL-17. Effector and central memory subsets develop with disparate kinetics in the lungs, draining lymph node and spleen. Notably, OVA-specific cells are poorly retained in the lungs after clearance of infection. We also show that intranasal vaccination leads to more antigen-specific CD8+ T cells in the lung-draining lymph node compared to scarification vaccination, but that an intranasal booster overcomes this difference. Together, our data show that this novel tool can be used to study multiple aspects of the CD8+ T cell response to F. tularensis. Use of this tool will enhance our understanding of immunity to this deadly pathogen.
由于缺乏关于保护性适应性免疫相关因素的知识以及缺乏获取这些知识的工具，预防兔热病的安全有效疫苗的研发进展受到了阻碍。CD8 + T细胞对于抵抗毒力强的土拉弗朗西斯菌菌株的保护性免疫至关重要，但迄今为止，还无法以抗原特异性方式研究这些细胞。在此，我们报告了一种在土拉弗朗西斯菌中表达模型抗原卵清蛋白（OVA）的工具的开发，该工具可用于研究CD8 + T细胞对该细菌的反应。我们证明，在用土拉弗朗西斯菌活疫苗株进行鼻内感染后，过继转移的OVA特异性CD8 + T细胞在第一周后扩增并产生IFN-γ，但不产生IL-17。效应细胞和中枢记忆亚群在肺、引流淋巴结和脾脏中以不同的动力学发展。值得注意的是，感染清除后，OVA特异性细胞在肺中的留存率很低。我们还表明，与划痕接种相比，鼻内接种可导致肺引流淋巴结中产生更多的抗原特异性CD8 + T细胞，但鼻内加强免疫可克服这一差异。总之，我们的数据表明，这种新型工具可用于研究CD8 + T细胞对土拉弗朗西斯菌反应的多个方面。使用该工具将增强我们对这种致命病原体免疫的理解。
