Positive and Negative Regulation of Natural Killer Cells After BMT

描述(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具有显著的移植物抗肿瘤效果。然而，严重的问题限制了HSCT的疗效，包括肿瘤复发、移植物排斥反应、移植物抗宿主病(GVHD)以及严重的免疫缺陷使患者高度容易受到机会性感染。自然杀伤(NK)细胞是先天免疫反应的重要组成部分，越来越多地被用作造血干细胞移植的治疗手段。然而，NK细胞及其调控的日益复杂，以及对移植后NK细胞发育/恢复的了解相对较少，严重阻碍了NK细胞作为一种免疫治疗手段的临床应用。由于不同的许可，NK亚群的存在和它们的功能可能有显著的不同。我们将基于令人兴奋的初步数据，证明小鼠NK细胞亚群对HSCT结果具有明显的相反和不同的影响，使用几个临床前模型评估同种或异基因HSCT后对病毒耐药性、肿瘤复发和供者植入/GVHD的影响。为此，我们提出了三个特定的目的：特定的目的1将建立在我们的数据基础上，证明Ly49G2代表了NK细胞的全球激活/发育标记，因为它在HSCT后占主导地位，或者具有普遍的激活，并且不依赖于MHC。这一目的将通过检测同源HSCT后对小鼠巨细胞病毒(MCMV)的抗性来研究该亚群和其他亚群扩大的潜在机制，并确定它们的功能作用。由于初步数据表明，在HSCT后确实可以观察到NK细胞与Ly49A+、Ly49G2+和Ly49C/I+亚群的许可，而在静息小鼠中没有观察到病毒耐药性，我们假设HSCT后的环境是理解NK细胞亚群相互作用的独特手段，Ly49家族在功能/许可方面是不同的。具体目标2将建立在我们令人兴奋的初步数据的基础上，表明宿主NK细胞亚群似乎能够相互调节，与异基因造血干细胞移植后供者造血植入方面的许可和执行“帮助”或“抑制”功能一致。这将表征这些似乎具有许可或未许可行为的亚群，并寻求扩大它们在同种异体造血干细胞移植中的体内有益影响。这一目标也将决定HSCT后对预后的长期影响，包括髓系和淋巴系重建以及移植物抗宿主病。具体目标3将建立在先前目标数据和新数据的基础上，以确定供者转移的NK细胞“助手”或“抑制/效应”亚群在同种或异基因造血干细胞移植后的抗肿瘤效果方面的潜在机制。这一目标将寻求通过给予免疫调节剂(IL-15和中和转化生长因子-2)来增强这些效应。最后，我们将确定使用针对肿瘤干细胞(CSC)群体的亚群进行过继NK细胞治疗的效果，这些群体可能是NK细胞治疗的关键靶点(使用亚群)。这些目标不仅有助于确定小鼠NK细胞亚群的功能，还将有助于开发临床上利用人类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.