Enhancement of targeting HIV vaccine to dendritic cell

描述（由申请人提供）：树突状细胞（dc）是一种专业的抗原呈递细胞（apc），具有启动初始T和B免疫细胞的独特能力，从而诱导初级免疫反应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抗原靶向DC表面分子来增强免疫反应。然而，它们在外周组织中的固有数量较少限制了dc作为免疫治疗或疫苗靶点的使用。增加DC种群将提供一种增强免疫反应的合理途径。本研究旨在验证将DC生长因子（FL、GM-CSF）或激活剂（CD40L）结合到病毒样颗粒（VLPs）中，通过扩大和/或激活DC，以及VLPs同时靶向DC群体，从而增强免疫反应的假设。造血生长因子如fit3配体（FL）和粒细胞-巨噬细胞集落刺激因子（GM-CSF）被证明可以扩大dc亚群，从而增加免疫反应。CD40配体（CD40L）也被证实与dc上的CD40结合。CD40L的相互作用诱导DCs活化为专业apc。此外，CD40L直接激活dc不需要CD4+ T辅助细胞（Th）来增强免疫应答，这对艾滋病患者具有治疗意义。HIV gag和env基因在细胞内的共表达导致产生含有env蛋白和gag蛋白核心的VLPs。由于缺乏核酸，VLPs是安全的，并且已知可诱导细胞和体液免疫反应。为了将SHIVVLPs （SIV Gag核心和HIV SF162 Env蛋白）靶向到DC和扩大DC群体，我们将以膜结合的形式表达FL、GM-CSF或CD40L，并产生纳入SHIVVLPs的FL、GM-CSF或CD40L（特异性目的1）。用含有膜锚定DC生长因子（FL、GM-CSF）或CD40L的SHIV VLPs免疫小鼠后的免疫应答将通过测定HIV Env蛋白特异性抗体滴度、细胞因子产生、HIV Env和SIV Gag特异性CTL活性以及分析DC亚群亚群来检测（特异性目的2）。作为一项长期目标，将在非人类灵长类动物模型中测试将VLPs靶向dc的有效性，以设计更有效的艾滋病疫苗。

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.