Tracking Immune Activation by Stress Proteins In Vivo

描述(由申请人提供)：含有与应激蛋白相关的多肽的疫苗是已知最有效的T细胞免疫原。然而，它们激活免疫细胞的确切机制仍不清楚。为了解决这个问题，我们将跟踪激活的树突状细胞(DC)和CD8+T细胞，用融合到应激蛋白HSP70的抗原免疫小鼠，并确定它们的反应需要哪些细胞因子和细胞表面受体。我们的初步研究表明，hspTO融合疫苗比抗原单独或与其他佐剂一起诱导更有效和更持久的特异性CD8+T细胞反应。我们的基本假设是，抗原/HSP70融合是有效的疫苗，因为它们刺激DC为CD8+T细胞激活提供最佳的微环境。这种微环境以高抗原密度和强共刺激作用为特征。为了测试这一点，我们将跟踪体内引流淋巴结中DC和CD8+T细胞的反应，以及外周产生的效应和记忆CD8+T细胞。我们的建议的新方面包括：1)定量激活的DC呈递的抗原的数量，2)HSP70融合蛋白对DC寿命的影响，3)确定已报道的几种HSP70受体中的哪一种是向体内的DC传递激活信号所必需的或足够的，以及4)确定我们的疫苗具有CD8+T细胞记忆的深刻效应所需的共刺激和细胞因子。这些实验的结果将使我们能够理性地操纵应激蛋白诱导的反应，最终目标是最大限度地将它们用于癌症治疗。

DESCRIPTION (provided by applicant): Vaccines containing peptides linked to stress proteins are the most potent known T cell immunogens. However, the precise mechanisms by which they activate immune cells remain unclear. To address this, we will track activated dendritic cells (DCs) and CD8+ T cells in mice immunized with antigens fused to the stress protein hsp70, and determine which cytokines and cell surface receptors are required for their responses. Our preliminary studies reveal hspTO fusion vaccines elicit much more potent and durable specific CD8+ T cell responses than antigen alone or with other adjuvants. Our underlying hypothesis is that antigen/hsp70 fusions are potent vaccines because they stimulate DCs to provide an optimal microenvironment for CD8+ T cell activation. This microenvironment is defined by high antigen density and strong costimulation. To test this, we will track in vivo DC and CD8+ T cell responses in draining lymph nodes, and the resultant effector and memory CD8+ T lymphocytes in the periphery. Novel aspects of our proposal include: 1) quantifying the amount of antigen presented by activated DCs, 2) the effect hsp70 fusion proteins have on DC lifespan, 3) determining which of the several reported hsp70-receptors are necessary or sufficient for delivering activation signals to DCs in vivo, and 4) determining the costimulatory and cytokines required for the profound effect our vaccine has CD8+ T cell memory. The results of these experiments will allow us to manipulate stress protein-induced responses rationally with the ultimate goal of maximizing their use for cancer therapy.