FUNCTIONAL COOPERATION BETWEEN TROPHOBLAST HLA-G AND B7 FAMILY

摘要--项目11 背景资料。淋巴细胞的刺激需要由抗原提供的两个协同信号的传递 呈现细胞。第一种信号由人类白细胞抗原(人类白细胞抗原)提供，而第二种信号由人类白细胞抗原提供 由共刺激分子B7家族的一名成员。然而，与经典的抗原提呈细胞不同， 滋养层细胞具有这两类分子的独特组合。具体地说，滋养细胞 结构性地表达非经典的HLA-G分子以及新发现的B7家族成员B7- H1。体外和体内研究表明，B7和HLA蛋白的表达可以抑制白细胞 激活和改变细胞因子分泌，这些蛋白的异常表达可能有助于 癌症和自身免疫性疾病等疾病。我们的初步数据显示滋养层细胞与 HL_A-G和B7-H1还抑制T细胞产生促炎细胞因子干扰素-γ，提示 滋养层细胞使用这些分子来保护胎儿半异体移植。我们和其他人也 证明氧和促炎细胞因子与子痫前期和 早产，改变滋养细胞相关的B7-H1和HLA-G的表达。因此，改变的表达方式 胎盘中异常氧和/或细胞因子状态引起的滋养层细胞HLA和B7s可能 导致滋养层细胞抑制母体白细胞的能力降低或增强。 具体目标。滋养层细胞表达人类白细胞抗原和B7家族独特成员的研究 细胞提出了这样一个问题：这些分子是否在功能上相互协作，向淋巴细胞传递信号 类似于这些家庭的古典成员的举止。项目II的具体目标是：1)确定 正常妊娠和病理妊娠中人类白细胞抗原-G和B7-H1分子的相对表达水平 确定滋养层细胞B7-H1的存在是否影响滋养层细胞HLA-G对母体的影响 T淋巴细胞；3)检测B7-H1是否影响表达HLA-G1的抗原提呈活性 滋养层细胞系。在目标1中，组织和纯化的滋养层细胞来自正常，子痫前期， 并将通过分子、组织学和流式细胞仪技术对早孕进行检查 确定在不良妊娠中这些蛋白质的平衡是否被抵消。在目标2中，我们将 进行功能分析，比较单独和联合使用人类白细胞抗原和B7家族分子的能力 调节白细胞功能。最后，Aim 3旨在确定滋养层细胞相关的人类白细胞抗原-G 可以在母婴界面提供抗病毒保护。在这里，我们将测试HLA-G是否可以呈现 病毒多肽与T细胞的结合，以及B7-H1的存在是否影响T细胞的这一能力。

ABSTRACT-PROJECT 11 Background. Stimulation of lymphocytes requires the delivery of two cooperating signals provided by antigen presenting cells. The first signal is provided by human leukocyte antigens (HLA), while the second is provided by a member of the B7 family of costimulatory molecules. Unlike classical antigen presenting cells, however, trophoblast cells possess a distinctive combination of both classes of molecules. Specifically, trophoblast cells constitutively express non-classical HLA-G molecules as well as the newly discovered B7 family member, B7- H1. In vitro and in vivo studies have shown that expression of the B7 and HLA proteins can inhibit leukocyte activation and alter cytokine secretion, and that aberrant expression of these proteins can contribute to conditions such as cancer and autoimmune disease. Our preliminary data show that trophoblast-associated Hl_A-G and B7-H1 also inhibits production of the proinflammatory cytokine interferon-y by T cells, suggesting that trophoblast cells use these molecules for protection of the fetal semiallograft. We and others have also demonstrated that oxygen and proinflammatory cytokines, which are associated with preeclampsia and preterm delivery, alter expression of trophoblast-associated B7-H1 and HLA-G. Thus, altered expression of trophoblast HLA and B7s precipitated by abnormal oxygen and/or cytokine conditions in the placenta could lead to the reduced or enhanced ability of trophoblast cells to inhibit maternal leukocytes. Specific goals. The findings of the expression of unique members of the HLA and B7 families by trophoblast cells raises the question of whether these molecules functionally cooperate to deliver signals to lymphocytes in a manner similar to classical members of these families. The Specific Aims of Project II are to 1) determine the relative levels of expression of members of HLA-G and B7-H1 in normal and pathologic pregnancies; 2) determine whether the presence of trophoblast B7-H1 influences the effects of trophoblast HLA-G on maternal T lymphocytes; 3) examine whether B7-H1 influences antigen presentation activity of HLA-G1-expressing trophoblast cell lines. In Aim 1, tissue and purified trophoblast cells from placentas of normal, preeclamptic, and preterm pregnancies will be examined by molecular, histological, and flow cytometric techniques to determine whether the balance of these proteins is offset in compromised pregnancies. In Aim 2, we will perform functional assays to compare the ability of HLA and B7 family molecules, alone and in combination, to regulate leukocyte function. Finally, Aim 3 is designed to determine whether trophoblast-associated HLA-G can provide anti-viral protection at the maternal-fetal interface. Here, we will test whether HLA-G can present viral peptides to T cells, and whether the presence of B7-H1 affects its ability to do so.