De Pascalis Roberto, Mittereder Lara, Kennett Nikki J, Elkins Karen L
Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
Infect Immun. 2016 Mar 24;84(4):1054-1061. doi: 10.1128/IAI.01348-15. Print 2016 Apr.
We previously identified potential correlates of vaccine-induced protection against Francisella tularensis using murine splenocytes and further demonstrated that the relative levels of gene expression varied significantly between tissues. In contrast to splenocytes, peripheral blood leukocytes (PBLs) represent a means to bridge vaccine efficacy in animal models to that in humans. Here we take advantage of this easily accessible source of immune cells to investigate cell-mediated immune responses against tularemia, whose sporadic incidence makes clinical trials of vaccines difficult. Using PBLs from mice vaccinated with F. tularensis Live Vaccine Strain (LVS) and related attenuated strains, we combined the control of in vitro Francisella replication within macrophages with gene expression analyses. The in vitro functions of PBLs, particularly the control of intramacrophage LVS replication, reflected the hierarchy of in vivo protection conferred by LVS-derived vaccines. Moreover, several genes previously identified by the evaluation of splenocytes were also found to be differentially expressed in immune PBLs. In addition, more extensive screening identified additional potential correlates of protection. Finally, expression of selected genes in mouse PBLs obtained shortly after vaccination, without ex vivo restimulation, was different among vaccine groups, suggesting a potential tool to monitor efficacious vaccine-induced immune responses against F. tularensis. Our studies demonstrate that murine PBLs can be used productively to identify potential correlates of protection against F. tularensis and to expand and refine a comprehensive set of protective correlates.
我们之前利用小鼠脾细胞确定了疫苗诱导的针对土拉弗朗西斯菌的保护性反应的潜在相关因素,并进一步证明不同组织间基因表达的相对水平存在显著差异。与脾细胞不同,外周血白细胞(PBLs)是一种将动物模型中的疫苗效力与人类中的疫苗效力联系起来的手段。在此,我们利用这种易于获取的免疫细胞来源,来研究针对兔热病的细胞介导免疫反应,兔热病的散发性使得疫苗临床试验变得困难。使用接种土拉弗朗西斯菌活疫苗株(LVS)及相关减毒株的小鼠的PBLs,我们将巨噬细胞内土拉弗朗西斯菌体外复制的控制与基因表达分析相结合。PBLs的体外功能,特别是巨噬细胞内LVS复制的控制,反映了LVS衍生疫苗赋予的体内保护等级。此外,之前通过脾细胞评估鉴定出的几个基因在免疫PBLs中也被发现存在差异表达。另外,更广泛的筛选确定了其他潜在的保护性相关因素。最后,在接种疫苗后不久获得的、未经体外再刺激的小鼠PBLs中,所选基因的表达在不同疫苗组之间存在差异,这表明这是一种监测针对土拉弗朗西斯菌的有效疫苗诱导免疫反应的潜在工具。我们的研究表明,小鼠PBLs可有效地用于确定针对土拉弗朗西斯菌的保护性反应的潜在相关因素,并扩展和完善一套全面的保护性相关因素。