Enhancement of targeting HIV vaccine to dendritic cell

描述（由申请人提供）：树突状细胞（DC）是专职抗原呈递细胞（APC），具有引发初始T和B免疫细胞的独特能力，从而诱导初次免疫应答并允许建立免疫记忆。DC的这种独特能力已被用于通过调节Ag以靶向DC表面分子来增强免疫应答。然而，它们在外周组织中固有的少量限制了DC作为免疫治疗或疫苗靶点的使用。增加DC群体将提供增强免疫应答的合理方式。该提议旨在检验将DC生长因子（FL、GM-CSF）或活化剂（CD 40 L）掺入病毒样颗粒（VLP）中将通过扩增和/或活化DC以及同时将VLP靶向DC群体而导致免疫应答增强的假设。造血生长因子如fit 3配体（FL）和粒细胞-巨噬细胞集落刺激因子（GM-CSF）显示出扩增DC亚群，从而增加免疫应答。CD 40配体（CD 40 L）也被证明与DC上的CD 40结合。CD 40 L的相互作用诱导DC活化为专职APC。此外，通过CD 40 L直接激活DC不需要CD 4 + T辅助（Th）细胞来增强免疫应答，这对AIDS患者具有治疗意义。HIV gag和env基因在细胞中的共表达导致产生含有具有Gag蛋白核心的Env蛋白的VLP。由于缺乏核酸，VLP是安全的，并且已知可诱导细胞和体液免疫应答。为了将SIV VLP（SIV Gag核心和HIV SF 162 Env蛋白）靶向DC和扩增DC群体，我们将以膜结合形式表达FL、GM-CSF或CD 40 L，并产生掺入SIV VLP中的FL、GM-CSF或CD 40 L（具体目标1）。通过测定HIV Env蛋白特异性抗体滴度、细胞因子产生和对HIV Env和SIV Gag特异性的CTL活性以及通过分析DC亚群的亚群，检查用含有膜锚定DC生长因子（FL、GM-CSF）或CD 40 L的SHIV VLP免疫后小鼠中的免疫应答（具体目的2）。作为长期目标，将在非人灵长类动物模型中测试VLP靶向DC的功效，以设计更有效的AIDS疫苗。

DESCRIPTION (provided by applicant): Dendritic cells (DCs) are professional antigen-presenting cells (APCs) with a unique ability to prime naive T and B immune cells, thus inducing primary immune responses and permitting establishment of immunological memory. This unique ability of DCs has been utilized to enhance immune responses by modulating the Ag to be targeted to DC surface molecules. However, their intrinsic small number in peripheral tissues limits the use of DCs as immunotherapy or vaccine targets. Increasing DC populations would provide a rational way to enhance immune responses. This proposal is designed to test the hypothesis that incorporation of DC growth factors (FL, GM-CSF) or an activator (CD40L) into virus-like particles (VLPs) will lead to enhancement of immune responses by expanding and/or activating DCs as well as targeting of the VLPs to DC populations simultaneously. Hematopoietic growth factors such as fit3 ligand (FL) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were shown to expand subsets of DCs and thus to increase immune responses. CD40 ligand (CD40L) was also demonstrated to bind to CD40 on DCs. Interaction of CD40L induces the activation of DCs into professional APCs. In addition, direct activation of DCs by CD40L does not require a CD4+ T helper (Th) cell in enhancing immune responses, which has therapeutic implications for AIDS patients. Coexpression of HIV gag and env genes in cells results in production of VLPs containing Env protein with Gag protein core. Lacking nucleic acids,VLPs are safe and known to induce both cellular and humoral immune responses. For both targeting SHIV VLPs (SIV Gag core and HIV SF162 Env protein) to DCs and expanding DC populations, we will express FL,GM-CSF, or CD40L in membrane-bound form and produce FL, GM-CSF, or CD40L incorporated into SHIVVLPs (specific aim 1). Immune responses in mice after immunization with SHIV VLPs containing membrane-anchored DC growth factors (FL, GM-CSF) or CD40L will be examined by determining HIV Env protein specific antibody titers, cytokine production, and CTL activities specific to HIV Env and SIV Gag as well as by analyzing subpopulations of DC subsets (specific aim 2). As a long-term objective, the efficacy of targeting VLPs to DCs will be tested in a non-human primate model for designing a more effective AIDS vaccine.