Applications of single chain MHC-1 molecules

描述（由申请人提供）：MHC I类分子以出色的特异性将肽呈递给CD 8+细胞溶解性T淋巴细胞，从而确保准确鉴定病毒感染细胞和肿瘤细胞。然而，I类分子的几种功能受到肽和/或β 2 m与重链解离的限制。事实上，用肽和/或β 2 m阻断I类重链组装是肿瘤和病毒逃避CD 8 + T细胞检测的主要途径。为了规避I类分子由于其倾向于分解而受到的限制，我们将I类分子设计为具有肽-间隔区-β 2 m-间隔区-重链组成的单链三聚体（SCT）。我们最近发表的研究结果表明，SCT具有显着的特性，包括在细胞表面的非凡稳定性和I类/肽特异性T细胞和抗体的有效刺激。在这项资助中，我们将定义SCT作为有效免疫刺激剂的机制，并测试其在基于DC的免疫疗法中以及用作抗肿瘤或病毒的DNA疫苗时相对于天然I类分子的独特优势。特别重要的是，这些发现将确定SCT在DNA疫苗接种后是否通过交叉致敏或直接呈递给CD 8 + T细胞来呈递抗原。此外，我们将测试SCT体外扩增CD 8 + T细胞的敏锐能力是否来自与抑制性受体的相互作用受损和/或对共刺激的依赖性降低。此外，我们将利用SCT的独特能力，引发MHC限制性抗体，以提高单克隆抗体的疾病相关的I类/肽复合物。这种mAb对于定量疾病进展期间特定I类/肽复合物的表达以及确定这与CD 8 + T细胞针对病毒和肿瘤的活化和效应功能如何相关将是非常宝贵的。

DESCRIPTION (provided by applicant): MHC class I molecules present peptide to CD8+ cytolytic T lymphocytes with brilliant specificity, thus ensuring accurate identification of virus-infected and tumor cells. However, several of the functions of class I molecules are limited by peptide and/or beta2m dissociation from the heavy chain. Indeed blocking class I heavy chain assembly with peptide and/or beta2m are major pathways used by tumors and viruses to evade detection by CD8+ T cells. To circumvent limitation of class I as a consequence of their propensity to disassemble, we have engineered class I molecules as single chain trimers (SCTs) with the composition of peptide--spacer--beta2m--spacer--heavy chain. Our recently published findings have shown that SCT have remarkable properties including extraordinary stability at the cell surface and potent stimulation of class I/peptide-specific T cells and antibodies. In this grant we will define the mechanisms by which SCT are potent immune stimulators and test their unique advantages over native class I molecules in DC based immunotherapies and when used as DNA vaccines against tumors or viruses. Of particular significance, these findings will determine whether SCT present antigen following DNA vaccination by cross priming or direct presentation to CD8+ T cells. Furthermore we will test whether the keen ability of SCT to expand CD8+ T cells ex vivo results from impaired interactions with inhibitory receptors and/or less dependency on costimulation. In addition we will exploit the unique ability of SCT to elicit MHC-restricted antibodies to raise mAbs to disease-relevant class I/peptide complexes. Such mAb will be invaluable for quantifying expression of specific class I/peptide complexes during disease progression and determine how this correlates with the activation and effector function of CD8+ T cells against viruses and tumors.