Modeling HTLV-1 infection and cellular immune response in HLA-A2-transgenic mice

描述（由申请人提供）：迄今为止，缺乏合适的小动物模型阻碍了我们在体内系统中了解HTLV-1的免疫和神经发病机制。这是由于HTLV-1包膜与小鼠细胞的融合效率低下。最近，一种嵌合HTLV-1病毒被开发出来，它利用moloney -小鼠白血病病毒的包膜基因，从而允许嵌合病毒与小鼠细胞融合。利用这种嵌合病毒，我们最近证明，在cd11c - dtr转基因小鼠中，dc的缺失增强了对HTLV-1无细胞感染的易感性（Rahman等，J. Immunol, in press）。这些小鼠经过独特设计，可以在体内选择性地消耗dc。与猿猴和人类细胞不同，小鼠细胞通常对白喉毒素（DT）具有折射性。在CD11c-DTR- tg小鼠中，DTR转基因与CD11c启动子（主要在小鼠脾dc中表达）融合，允许在DT存在的情况下完全消融dc，而不影响其他apc，如B细胞和巨噬细胞。该系统已被用于研究dc在几种病毒的发病机制中的作用，包括LCMV、HSV-1和最近的HTLV-1 （Rahman等，J. Immunol.）。（待印）。然而，由于小鼠MHC背景，这些小鼠在研究人类MHC i类相关免疫反应（例如在HAM/TSP患者中观察到的免疫反应）时仍然存在问题。这个问题已经在一个单独的小鼠品系中得到了解决，称为HHD II系，它表达人类HLA- a2.1分子，并且被敲除小鼠H-2Db MHC I类分子和β -2微球蛋白，因此只携带人类HLA I类分子。我们之前已经在这些小鼠中证明了免疫和诱导tax11 -19特异性CTL反应(Manuel等人，J. Leuk。医学杂志。, 2009)。本研究试图在小鼠中产生一种新的转基因菌株（HHD II/DTR-Tg）来研究在dc缺失和存在的情况下HTLV-1感染和随后hla - a2限制性细胞免疫反应。新产生的菌株可以进一步用于研究htlv -1介导的免疫发病过程中DC:T细胞相互作用的机制方面。在体内选择性消融树突状细胞的能力为探索这种独特细胞群在各种感染和疾病模型中的作用提供了有力的工具。本文提出的HHD II/DTR-Tg新杂交菌株的开发，将极大地促进HTLV-1免疫/神经发病机制的未来研究，并为科学界提供一个有价值的工具。

DESCRIPTION (provided by applicant): To date, the lack of a suitable small animal model has hindered our quest to understand the immuno- and neuropathogenesis of HTLV-1 in an in vivo system. This is due to the inefficient fusion of HTLV-1 envelope with murine cells. Recently, a chimeric HTLV-1 virus has been developed that utilizes the envelope gene of the Moloney-murine leukemia virus thereby allowing fusion of the chimeric virus with murine cells. Utilizing this chimeric virus we have recently demonstrated that depletion of DCs enhances susceptibility to cell-free infection of HTLV-1 in CD11c-DTR-transgenic mice (Rahman et al., J. Immunol, in press). These mice are uniquely designed to selectively deplete DCs in vivo. Murine cells, unlike simian and human cells, are generally refractive to diphtheria toxin (DT). The fusion of DTR transgene to the CD11c promoter (largely expressed in murine splenic DCs) in CD11c-DTR-Tg mice allows for the complete ablation of DCs in the presence of DT without affecting other APCs such as B cells and macrophages. This system has been used to study role of DCs in the pathogenesis of several viruses including LCMV, HSV-1, and recently HTLV-1 (Rahman et al., J. Immunol., in press). However, these mice still pose problem in studying human MHC class I-associated immune responses (such as those observed in HAM/TSP patients) due to the mouse MHC background. This issue has been addressed in a separate strain of mice, known as line HHD II, which express human HLA-A2.1 molecule and are knockout for the mouse H-2Db MHC class I molecule and beta2-microglobulin thereby carrying only human HLA class I molecules. We have previously demonstrated the immunization and induction of Tax 11-19-specific CTL response in these mice (Manuel et al., J. Leuk. Biol., 2009). The study proposed herein attempts to generate a new transgenic strain (HHD II/DTR-Tg) of mice to study HTLV-1 infection and subsequent HLA-A2-restrticted cellular immune response in the absence and presence of DCs. The newly generated strain could be further utilized to investigate mechanistic aspects of DC:T cell interaction during HTLV-1-mediated immunopathogenesis. The ability to selectively ablate DCs in vivo offers a powerful tool to explore the role of this unique cell population in various infection and disease models. The development of a new hybrid strain (HHD II/DTR-Tg), as proposed here, will greatly facilitate future studies of HTLV-1 immuno/neuropathogenesis in addition to providing a valuable tool to the scientific community in general. PUBLIC HEALTH RELEVANCE: The proposed studies are relevant to public health and will reveal significant information concerning the dendritic cells-regulated T cell responses during complex autoimmune/neuroinflammatory diseases such as HAM/TSP and multiple sclerosis. Additionally the results of these studies will shed light on the dynamics of immune cell interactions during chronic viral infections such as HTLV-1, HIV-1, hepatitis virus and herpes simplex virus.