Human T Cell Responses to Vaccinia Vaccine

描述(申请人提供)：迫切需要开发更安全的天花疫苗。一种方法是使用改良的痘苗病毒安卡拉(MVA)，这是一种高度减毒的痘苗病毒，不在人类细胞中复制。然而，与痘苗病毒相比，MVA的免疫原性较低，可能需要更高的剂量和更频繁的增强。对使用活的减毒病毒和可能存在外来病原体的安全问题也仍然存在。替代方法包括开发灭活病毒或重组蛋白疫苗。然而，疫苗的开发受到阻碍，因为人们对哪些蛋白质在产生对天花的保护性免疫反应中发挥重要作用知之甚少。最近，4种诱导中和抗体的包膜蛋白被鉴定出来，所有4种基因组合的DNA疫苗可以保护小鼠免受致死性牛痘病毒的感染。虽然疫苗需要诱导强烈的T细胞反应，但除了中和抗体外，还没有关于T细胞识别的牛痘蛋白靶标的信息。特别是，CD4T细胞需要增强B细胞、T细胞和对裂解病毒的先天免疫反应。作为第一步，将对以前接种过痘苗病毒的健康成年人的外周血单核细胞进行病毒特异性T细胞反应测试。这项研究的目的是：1)测量人类T细胞对痘苗病毒结构蛋白的反应频率；2)确定上述4种囊膜蛋白中的主要CD4和CD8 T细胞表位；3)分析免疫后T细胞对这些表位的反应频率。预计这项工作将为检测和监测大多数人的牛痘特异性T细胞反应提供新的工具，并将有助于制定天花疫苗开发的新战略。

DESCRIPTION (provided by applicant): There is an urgent need to develop safer smallpox vaccines. One approach is the use of modified vaccinia virus Ankara (MVA), a highly attenuated vaccinia virus that does not replicate in human cells. In comparison to vaccinia virus, however, MVA is less immunogenic and may require higher doses and more frequent boosts. There also remain safety concerns about the use of a live attenuated virus and the potential presence of adventitious pathogens. Alternative approaches include the development of inactivated virus or recombinant protein vaccines. However, vaccine development is hampered because little is known about what proteins play an important role in the generation of protective immune responses to smallpox. Recently, 4 envelope proteins that induce neutralizing antibodies were identified, and DNA vaccination with a combination of all 4 genes protected mice from a lethal vaccinia infection. Although a vaccine will need to induce strong T cell responses, in addition to neutralizing antibodies, no information is available about the vaccinia protein targets recognized by T cells. In particular, CD4 T cells are required to enhance B cell, T cell, and innate immune responses to lytic viruses. As a first step, peripheral blood mononuclear cells from healthy adults previously immunized with vaccinia virus will be tested for virus-specific T cell responses. The goals of this study are: 1) to measure the frequencies of human T cell responses to vaccinia structural proteins; 2) to identify major CD4 and CD8 T cell epitopes within the above 4 envelope proteins; and 3) to analyze the frequencies of the T cell responses to these epitopes post-vaccination. It is anticipated that this work will provide new tools for the detection and monitoring of vaccinia-specific T cell responses from most individuals and will help develop new strategies for smallpox vaccine development.