Positive and Negative Regulation of Natural Killer Cells After BMT

描述（由申请人提供）：造血干细胞移植（HSCT）越来越多地用于癌症治疗，并已被证明对几种癌症提供显著的移植物抗肿瘤作用。然而，重要的问题限制了HSCT的疗效，包括肿瘤复发、移植物排斥、移植物抗宿主病（GVHD）和长期的免疫缺陷，使患者极易受到机会性感染。自然杀伤（NK）细胞是先天免疫反应的关键组成部分，越来越多地被用作造血干细胞移植的治疗手段。然而，随着NK细胞及其调控的日益复杂，以及对造血干细胞移植后NK细胞发育/恢复的了解相对较少，严重阻碍了NK细胞作为免疫治疗手段的临床应用。NK子集存在，并且由于不同的许可，它们的功能可能显著不同。我们将建立令人兴奋的初步数据，证明小鼠NK细胞亚群对HSCT结果有明显的相反和不同的影响，使用几个临床前模型评估同源或异体HSCT后病毒耐药性、肿瘤复发和供体移植/GVHD的影响。为此，我们提出了3个具体目标：具体目标1将建立在我们的数据基础上，证明Ly49G2代表NK细胞的全局激活/发育标志物，因为它在HSCT后占主导地位或具有一般激活并且独立于MHC。本研究的目的是研究这一亚群和其他亚群扩增的机制，并确定它们在基因移植后对小鼠巨细胞病毒（MCMV）的抗性中所起的功能作用。由于初步数据表明，NK细胞与Ly49A+， Ly49G2+和Ly49C/I+亚群的许可确实可以在hsct后观察到，而不是在休息的小鼠中观察到病毒抗性，我们假设hsct后的环境代表了理解NK细胞亚群相互作用的独特手段，并且Ly49家族在功能/许可方面是多样化的。特异性目标2将建立在我们令人兴奋的初步数据基础上，这些数据表明，宿主NK细胞亚群似乎能够相互调节，与同种异体造血干细胞移植后供体造血移植的许可和执行“辅助”或“抑制”功能一致。这将描述这些亚群的特征，这些亚群表现为许可或未许可，并寻求扩大其在体内同种异体HSCT中的有益作用。这一目标也将确定HSCT后的长期影响，包括骨髓和淋巴细胞重建和GVHD。特异性目标3将建立在先前目标和新数据的基础上，以确定供体转移NK细胞“辅助”或“抑制/效应”亚群在同源或异体造血干细胞移植后抗肿瘤作用的潜在机制。这个目标将寻求通过免疫调节剂（IL-15和中和TGF-2）的施用来增强这些作用。最后，我们将确定使用亚群对癌症干细胞（CSC）群体的过继性NK细胞治疗的效果，这些群体可能代表NK细胞治疗的关键目标（使用亚群）。这些目标不仅有助于表征小鼠NK细胞亚群的功能，而且还有助于开发临床利用人类NK细胞或其亚群进行治疗的方法，特别是在HSCT和癌症的背景下，因为人类亚群得到了更好的定义。

DESCRIPTION (provided by applicant): Hematopoietic stem cell transplantation (HSCT) is increasingly used in cancer therapy and has been shown to provide significant graft-versus-tumor effects for several cancers. However, significant issues limit the efficacy of HSCT including relapse for the tumor, graft rejection, graft-versus-host disease (GVHD) and a profound period of immune deficiency leaving the patient highly susceptible to opportunistic infections. Natural killer (NK) cells represent critical components of the innate immune response and are being increasingly used as a therapeutic arm in HSCT. However, the increasing complexity of NK cells and their regulation along with the relatively sparse knowledge on NK cell development/recovery after HSCT seriously hampers clinical application of NK cells as an immunotherapeutic approach. NK subsets exist and may differ markedly in their function due to differential licensing. We will build on exciting preliminary data demonstrating that mouse NK cell subsets have markedly opposing and differential effects on HSCT outcome using several preclinical models assessing effects on viral resistance, tumor relapse and donor engraftment/GVHD after congenic or allogeneic HSCT. To do this we propose 3 SPECIFIC AIMS: Specific Aim 1 will build on our data demonstrating that Ly49G2 represents a global activation/development marker of NK cells as it is predominant after HSCT or with general activation and is independent of MHC. This aim will examine the mechanisms underlying the expansion of this and other subsets and determine their functional roles using resistance to mouse cytomegalovirus (MCMV) following congenic HSCT. As preliminary data indicate that NK cell licensing with Ly49A+, Ly49G2+, and Ly49C/I+ subsets can indeed be observed post-HSCT and not in resting mice with regard to viral resistance, we hypothesize that the environment post-HSCT represents a unique means to understand NK cell subset interactions and that the Ly49 family is diverse with regard to function/licensing. Specific Aim 2 will build on our exciting preliminary data demonstrating that host NK cell subsets appear capable of regulating each other consistent with licensing and performing "helper" or "suppressor" functions with regard to donor hematopoietic engraftment after allogeneic HSCT. This will characterize these subsets which appear to behave as licensed or unlicensed and seek to expand on their beneficial effects in vivo in allogeneic HSCT. This aim will also determine long-term effects on outcome after HSCT including myeloid and lymphoid reconstitution and GVHD. Specific Aim 3 will build on the data from the previous aims and new data to determine the mechanisms underlying the effects of donor transferred NK cell "helper" or "suppressor/effector" subsets with regard to anti-tumor effects after congenic or allogeneic HSCT. This aim will seek to augment these effects with administration of immunomodulating agents (IL-15 and neutralization of TGF-2). Finally, we will determine the effects of the adoptive NK cell therapy using subsets against cancer stem cell (CSC) populations which may represent critical targets for NK cell therapy (using subsets). These aims will not only aid in the characterization of mouse NK cell subsets with regard to function but will also help in developing means to clinically exploit human NK cells or their subsets therapeutically, particularly in the context of HSCT and cancer as human subsets become better defined.