Use of a Novel Antigen Loading Platform for Dendritic Cell-Based HIV Vaccines

描述（由申请人提供）：产生人类CD4+和CD8+ T细胞反应的有效方法是通过在树突状细胞（dc）上呈递抗原，树突状细胞（dc）是一种抗原呈递细胞（apc）系统，可刺激先天和适应性免疫反应。利用或靶向人类DC增强慢性HIV感染免疫的免疫策略在先前的研究中显示出希望，但需要进一步的研究来优化DC候选疫苗。理想情况下，针对dc的疫苗载体应递送相关的HIV抗原供呈递，同时激活dc上调表面共刺激分子并产生前Th1细胞因子，以启动HIV特异性的多功能CD4+和CD8+ T细胞反应。与各种减毒的病毒和细菌载体相比，单核细胞增生李斯特菌载体在免疫原性和安全性方面具有潜在的优势。在拟议的研究中，将研究使用表达HIV-1 gag （KBMA Lm-gag）的重组杀伤但代谢活性的单核细胞增生李斯特菌作为DC的抗原装载和激活/成熟平台，以评估其在慢性HIV感染DC疫苗配方中的潜在用途。具体目的是：(1)评估感染KBMA Lm-gag后，来自HIV血清阳性供体的dc的活化/成熟和抗原呈递效率；(2)评估来自HIV血清阳性患者的KBMA Lm-gag感染dc诱导初始T细胞形成具有高功能亲和力的多功能HIV-1 gag特异性CD4+和CD8+ T细胞的能力；(3)从免疫原性、免疫激活和CD4+ T细胞对HIV感染的易感性等方面研究对Lm的预先免疫是否会影响KBMA Lm -gag感染dc引起的应答。这些研究将有助于确定KBMA Lm-gag是否可以作为HIV免疫治疗的一个令人兴奋的新载体，利用或靶向dc来促进控制HIV感染。相关性（见说明）：艾滋病毒疫苗学领域最近遭遇挫折，激发了对抗原递送新模式的研究，以刺激艾滋病毒特异性免疫。为了从这一点出发，我们将从失败的尝试中获得的知识应用到拟议研究中使用的结构的设计和评估中。

DESCRIPTION (provided by applicant): An effective way to generate human CD4+ and CD8+ T cell responses is by presenting antigens on dendritic dells (DCs), a system of antigen presenting cells (APCs) that stimulate innate and adaptive immune responses. Immunization strategies that utilize or target human DCs to enhance immunity in chronic HIV infection have shown promise in previous studies, but further research is required to optimize DC vaccine candidates. Ideally, a DC-targeting vaccine vector should deliver relevant HIV antigens for presentation, while concurrently activating DCs to upregulate surface costimulatory molecules and produce pro Th1 cytokines in order to prime HIV-specific polyfunctional CD4+ and CD8+ T cell responses. Recombinant killed but metabolically active Listeria Monocytogenes vectors may fulfill these criteria, while offering potential advantages in terms of both immunogenicity and safety when compared with various attenuated viral and bacterial vectors. In the proposed research, the use of a recombinant killed but metabolically active Listeria Monocytogenes expressing HIV-1 gag (KBMA Lm-gag) will be investigated as an antigen loading and activation/maturation platform for DCs to evaluate its potential use in DC vaccine formulations for chronic HIV infection. The specific aims are to: (1) assess activation/maturation and efficiency of antigen presentation of DCs derived from HIV seropositive donors following infection with KBMA Lm-gag; (2) evaluate the ability of KBMA Lm-gag infected DCs derived from HIV seropositive patients to prime naive T cells to form polyfunctional HIV-1 gag-specific CD4+ and CD8+ T cells that possess high functional avidity; and (3) investigate whether pre-existing immunity to Lm impacts responses elicited by KBMA lm-gag infected DCs in terms of immunogenicity, immune activation, and susceptibility of CD4+ T cells to HIV infection. These studies will help determine whether KBMA Lm-gag may serve as an exciting new vector for HIV immunotherapy that utilizes or targets DCs to facilitate control of HIV infection. RELEVANCE (See instructions): The field of HIV vaccinology has recently suffered set-backs, inspiring the investigation of novel modes of antigen delivery in order to stimulate HIV-specific immunity. In order to move forward from this point, we have applied aspects of the knowledge gained from failed attempts to the design and evaluation of the construct utilized in the proposed study.