NK RECEPTOR FUNCTION IN HAEMATOPOIETIC STEM CELL TRANSPLANTATION

本项目所建议的研究的总体目标是阐明人类活动的机制， 自然杀伤细胞对正常自体体细胞具有耐受性;并定义了导致NK细胞增殖的条件。 通过同种异体细胞激活。已经提出，正常个体中的NK细胞通过以下方式实现自身耐受性： 仅赋予抑制性杀伤免疫球蛋白样受体（KIR）功能能力， 显示同源HLA配体。我们假设在异基因造血干细胞移植后植入NK细胞 细胞移植（HCT）是通过选择性无反应性的非自身抑制性KIR而获得对自身的耐受。之前 由于宿主中KIR配体的缺失而获得的耐受性、供体NK同种异体反应性可能是最明显的。 我们还假设，通过激活KIR识别HLA I类仅发生在HLA分子被激活时。 相比之下，当HLA分子是自身HLA分子时，激活KIR是同种异体抗原。 容忍或无反应。这些假设将在四个具体目标中进行测试：#1：确定NK 同种异体反应性受不同个体中激活KIR KIR 2DS 2、2DS 1和3DS 1的存在的影响。 KIR单倍型和HLA I类基因型的组合。这将通过确定（a）是否存在 活化KIR 2DS 1、2DS 2或3DS 1与NK细胞介导的同种异体反应相关， HLA-Cw和HLA-Bw 4 KIR-配体组，和（B）确定具有HLA-Cw和HLA-Bw 4 KIR-配体组的供体中的功能性NK表型。 作为自身MHC的激活KIR 2DS 1、2DS 2或3DS 1和相应KIR-HLA配体组的基因 抗原的#2：确定NK细胞同种异体反应性和自身耐受性的发展是否与活化 KIR在移植期间随着时间逐渐发展。我们还将检查移植的NK细胞 在任何时候都显示出与供体NK同种异体反应性不同的同种异体反应性。#3：（a）确定NK的收购 移植过程中对自身的耐受性。我们将确定是否在最初的一段时间内， KIR之后是非自身MHC特异性KIR的选择性无能。(b)确定是否存在T细胞在 同种异体移植影响抑制性KIR介导的NK反应。#4：确定NK受体对HLA的获得 NK细胞体外发育过程中的I类。我们将研究从获得的CD 34细胞中离体NK发育 脐带血和其他来源。我们将确定NK受体的顺序获得， 同一受体家族内受体的差异获得;确定其功能的获得， 对自身和同种异体反应的耐受性。我们将确定这些发育模式是否受到 HLA I类表型在基质培养环境中表达。相关性：这些研究将促进 为白血病患者选择供体和NK细胞治疗的新方法的开发 移植后输注以增强植入和白血病抗性。

The overall objectives for the studies proposed in this project is to delineate the mechanisms by which human Natural Killer cells are tolerant to normal autologous somatic cells; and define the conditions leading to NK cell activation by allogeneic cells. It has been proposed that NK cells in normal individuals achieve self-tolerance by endowing functional competence only to the inhibitory Killer immunoglobulin-like Receptors (KIR) for which they exhibit cognate HLA ligands. We hypothesize that engrafting NK cells following allogeneic hematopoietic stem cell transplantation (HCT) acquire tolerance to self through selective anergy of non-self inhibitory KIR. Prior to this acquisition of tolerance, donor NK alloreactivity due to missing KIR ligand in the host may be most evident. We also hypothesize that recognition of HLA class I by activating KIR only occurs when the HLA molecule is presented as an alloantigen,Jn contrast, when the HLA molecule is a self HLA molecule, the activating KIR is tolerized or unresponsive. These hypotheses will be tested in four specific aims: #1: Determine how NK alloreactivity is influenced by presence of activating KIRs KIR2DS2, 2DS1 and 3DS1 in individuals with different combinations of KIRhaplotypes andHLAclass I genotypes. This will beachieved bydetermining (a) if presence of the activating KIRs 2DS1, 2DS2 or 3DS1 correlates with a NK cell mediated alloresponse with specificity for the HLA-Cw and HLA-Bw4 KIR-ligand groups and (b) determine the functional NK phenotype in donors with the genes for the activating KIRs 2DS1, 2DS2 or 3DS1 and the corresponding KIR-HLA ligand group as self MHC antigen. #2: Determine if the development of NK cell alloreactivity and self tolerance associated with activating KIRs develops gradually over time during the period of engraftment. We will also examine if engrafting NK cells at any time display alloreactivity that deviates from donor NK alloreactivity. #3: (a) Determine acquisition of NK tolerance to self during'engraftment. We will determine if an initial period of hyper-responsiveness of inhibitory KIR is followed by selective anergy of non-self MHC-specific KIR. (b) Determine if the presence of T-cells in the allograft affects inhibitory KIR-mediated NK response. #4: Determine the acquisition of NK receptors to HLA class I during NK development in vitro. Wewill investigate NK development ex vivo from CD34 cells obtained from Cord Blood and other sources. We will determine the sequential acquisition of NK receptors, and differential acquisition of receptors within the same receptor family; determine their acquisition of function, tolerance to self and allogeneic reactivity. We will determine if these developmental patterns are affected by the HLA class I phenotype expressed in the stromal culture environment. Relevance: These studies will facilitate development of new methods for donor selection for patients with leukemia and for treatment with NK cell infusions post transplantation to enhance engraftment and leukemia resistance.