Zhang Xiugen, Cassis-Ghavami Farah, Eller Mike, Currier Jeff, Slike Bonnie M, Chen Xuemin, Tartaglia James, Marovich Mary, Spearman Paul
Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA.
J Virol. 2007 Jul;81(13):7022-33. doi: 10.1128/JVI.02654-06. Epub 2007 Apr 4.
Recombinant poxvirus vectors are undergoing intensive evaluation as vaccine candidates for a variety of infectious pathogens. Avipoxviruses, such as canarypox virus, are replication deficient in mammalian cells by virtue of a poorly understood species-specific restriction. Highly attenuated vaccinia virus strains such as modified vaccinia virus Ankara (MVA) are similarly unable to complete replication in most mammalian cells but have an abortive-late phenotype, in that the block to replication occurs post-virus-specific DNA replication. In this study, an identical expression cassette for human immunodeficiency virus gag, pro, and env coding sequences was placed in canarypox virus and MVA vector backbones in order to directly compare vector-borne expression and to analyze differences in vector-host cell interactions. Antigen production by recombinant MVA was shown to be greater than that from recombinant canarypox virus in the mammalian cell lines and in the primary human cells tested. This observation was primarily due to a longer duration of antigen production in recombinant MVA-infected cells. Apoptosis induction was found to be more profound with the empty canarypox virus vector than with MVA. Remarkably, however, the inclusion of a gag/pro/env expression cassette altered the kinetics of apoptosis induction in recombinant MVA-infected cells to levels equal to those found in canarypox virus-infected cells. Antigen production by MVA was noted to be greater in human dendritic cells and resulted in enhanced T-cell stimulation in an in vitro antigen presentation assay. These results reveal differences in poxvirus vector-host cell interactions that should be relevant to their use as immunization vehicles.
重组痘病毒载体作为多种传染性病原体的候选疫苗正在接受深入评估。禽痘病毒，如金丝雀痘病毒，由于一种尚未完全了解的种属特异性限制，在哺乳动物细胞中复制缺陷。高度减毒的痘苗病毒株，如改良痘苗病毒安卡拉株（MVA），同样无法在大多数哺乳动物细胞中完成复制，但具有流产晚期表型，即对复制的阻断发生在病毒特异性DNA复制之后。在本研究中，将用于人类免疫缺陷病毒gag、pro和env编码序列的相同表达盒分别置于金丝雀痘病毒和MVA载体骨架中，以便直接比较载体介导的表达，并分析载体与宿主细胞相互作用的差异。在测试的哺乳动物细胞系和原代人细胞中，重组MVA产生的抗原比重组金丝雀痘病毒产生的抗原更多。这一观察结果主要是由于重组MVA感染细胞中抗原产生的持续时间更长。发现空的金丝雀痘病毒载体比MVA诱导凋亡的作用更显著。然而，值得注意的是，包含gag/pro/env表达盒改变了重组MVA感染细胞中凋亡诱导的动力学，使其达到与金丝雀痘病毒感染细胞中相同的水平。MVA在人树突状细胞中产生的抗原更多，并在体外抗原呈递试验中导致增强的T细胞刺激。这些结果揭示了痘病毒载体与宿主细胞相互作用的差异，这对于它们作为免疫载体的应用应该是相关的。
