ROLE OF NON-CLASSICAL MHC CLASS I AND HSPs IN IMMUNITY

描述热休克蛋白（hsps）gp 96和hsp 70引起有效抗肿瘤免疫的独特能力似乎依赖于两个主要性质：（1）它们的肽依赖性能力，通过APC的受体介导的内吞作用和APC的MHC经典Ia类分子的代表，伴侣蛋白和引发针对抗原肽的适应性CTL应答，和（2）它们的肽-独立启动APC的能力。抗肿瘤CTL被认为是热休克蛋白介导的反应中的主要效应物。然而，越来越多的证据表明，NK细胞和其他识别非经典Ib类分子的不太明确的细胞毒性细胞类型也可能发挥关键作用。由于肿瘤通常下调MHC Ia类的表达，从而逃避免疫监视，我们观察到这些hsp可以产生抗肿瘤免疫应答，其不受Ia类限制，但可能涉及Ib类分子，这显然值得进一步探索。因此，我们建议测试的假设，热休克蛋白可以刺激经典的Ia类非限制性CTL（CCU-CTL），其效应器功能涉及Ib类分子。为此，我们已经开发了青蛙，非洲爪蟾，一个独特的和多功能的实验模型系统，其特征在于次要和主要的组织相容性定义的克隆动物和MHC类Ia-阴性可移植的胸腺淋巴瘤。该模型将用于通过体外杀伤测定和通过体内过继细胞转移和抗体消耗方案来评价gp 96和hsp 70产生抗肿瘤肽依赖性CTL效应子应答的能力，所述CTL效应子应答不受Ia类分子限制，但涉及Ib类分子。我们的系统模拟了针对已经下调其la类从而逃避免疫监视的肿瘤的反应。它也使我们能够研究热休克蛋白和Ib类分子之间的关系，这些分子被认为是细胞内应激和恶性肿瘤的指标。提出了四个具体目标： 目标1。抗肿瘤CCU-CTL的功能特点是什么？ 目标二。hsp 70和gp 96产生相似的抗肿瘤CCU-CTL效应子吗？ 目标3。hsp诱导的CCU-CTL应答在体内肿瘤免疫中有多重要？ 目标4。CCU-CTL与Ib类分子相互作用吗？

DESCRIPTION (provided by applicant): The unique ability of the heat shock proteins (hsps) gp96 and hsp70 to evoke potent anti-tumor immunity appears to rely on two main properties: (1) their peptide-dependent capacity to chaperone and elicit adaptive CTL responses against antigenic peptides through receptor-mediated endocytosis by APCs and representation by APC's MHC classical class la molecules and (2) their peptide-independent capacity to activate APCs. Anti-tumor CTLs are thought to be the main effectors in hsp-mediated responses. However, increasing evidence suggests that NK cells and other less well-characterized cytotoxic cell types recognizing non-classical class Ib molecules may also play a critical role. Since tumors commonly down-regulate expression of MHC class la, thereby escaping immune surveillance, our observation that these hsps can generate anti-tumor immune responses that are not class la-restricted, but possibly involve class Ib molecules, clearly merits further exploration. Therefore, we propose to test the hypothesis that hsps can stimulate classical class la unrestricted CTLs (CCU-CTLs) whose effector function involves class Ib molecules. To this end, we have developed in the frog, Xenopus, a unique and versatile experimental model system characterized by minor and major histocompatibility-defined cloned animals and a MHC class la-negative transplantable thymic lymphoma. This model will be used to evaluate, by in vitro killing assays and by in vivo adoptive cell transfer and antibody depletion protocols, the ability of gp96 and hsp70 to generate anti-tumor peptide-dependent CTL effector responses that are not restricted by class la molecules but involve class Ib molecules. Our system models responses against tumors that have down-regulated their class la thereby escaping immune surveillance. It also allows us to study the relationship between hsp and class Ib molecules that are postulated to act as indicators of intracellular stress and malignancy. Four specific aims are proposed: Aim 1. What are the functional characteristics of the anti-tumor CCU-CTLs? Aim 2. Do hsp70 and gp96 generate similar anti-tumor CCU-CTL effectors? Aim 3. How important is the hsp-generated CCU-CTL responses in tumor immunity in vivo? Aim 4. Do CCU-CTLs interact with class Ib molecules?