FUNCTION OF LYMPHOCYTE B1 INTEGRINS

整合素在免疫应答，淋巴细胞靶向， 和基因表达的调节。 最近，α 3和α 4链的 对整联蛋白VLA 3和4进行克隆和测序。 VLA 3是一种纤连蛋白 (FN)/胶原/层粘连蛋白受体。 VLA 4是a）FN受体，B） 血管细胞粘附分子-1（VCAM-1），其表达在血管内皮细胞上， 活化的内皮细胞表面，和c）淋巴细胞的归巢受体 派伊尔淋巴结 VLA 5是一种经典的FN受体，其识别 FN细胞结合结构域的RGD序列。 每种整合素都在以下方面发挥作用： 淋巴细胞功能，因此是一种潜在的诊断和 免疫性疾病的治疗靶点。 为了阐明VLA 3 -5/配体相互作用的机制，提出1） 为了鉴定胶原蛋白、层粘连蛋白和FN分子中的VLA 3结合位点， 使用在转染细胞中表达的重组VLA 3和配体， 片段或合成肽，2）鉴定候选配体结合 VLA 3 -5分子上的位点通过标记的 从配体中识别的结合位点合成肽 分子（例如，VLA 4的CS-1肽，VLA 5的含RGD肽）， 整合素，和3）检查a）突变的影响， 鉴定的配体结合位点，B）引入所述配体结合位点的作用， 患者中β 2或β 3整联蛋白的功能抑制突变[例如， Glanzmann血栓无力症（β 3链中的Asp 119至Tyr）]进入 β 1整合素的相应位点对VLA 3 -5功能的影响。 在 为了完成所提出的工作，稳定转染CHO细胞系 其在细胞表面表达大量重组VLA 3或VLA 4种类， 表面将建立（VLA 5过度生产细胞已经 可用）。 这些实验将分析VLA 3的共同和具体机制， 5/配体相互作用。 修饰这些相互作用的肽可以 调节淋巴细胞、单核细胞和其他细胞的靶向和功能 参与免疫疾病发病机制的细胞。

Integrins play important roles in immune response, lymphocyte targeting, and regulation of gene expression. Recently, alpha3 and alpha4 chains of integrins VLA3 and 4 were cloned and sequenced. VLA3 is a fibronectin (FN)/collagen/laminin receptor. VLA4 is a) a FN receptor, b) receptor for vascular cell adhesion molecule-1 (VCAM-1) which is expressed on an activated endothelial cell surface, and c) a homing receptor of lymphocytes for Peyer's patch. VLA5 is a classical FN receptor which recognizes the RGD sequence of a FN cell binding domain. Each integrin plays a role in lymphocyte function, and therefore is a potential diagnostic and therapeutic target in immunologic diseases. To elucidate the mechanism of VLA3-5/ligands interaction, it is proposed 1) to identify the VLA3 binding sites in collagen, laminin and FN molecules by using the recombinant VLA3 expressed in transfected cells and ligand fragments or synthetic peptides, 2) to identify candidate ligand binding sites on VLA3-5 molecules by chemical cross-linking of the labeled synthetic peptides from the identified binding sites in the ligand molecules (e.g. CS-1 peptide for VLA4, RGD containing peptide for VLA5) to integrins, and 3) to examine a) the effects of the mutation of the identified ligand binding sites, b) the effects of the introduction of the function inhibiting mutations in beta2 or beta3 integrin in patients [e.g. Glanzmann's thrombasthenia (Asp 119 to Tyr in beta3 chain)] into the corresponding site of beta1 integrin on the functions of the VLA3-5. In order to accomplish the proposed work the stably transfected CHO cell lines which express a large quantity of recombinant VLA3 or VLA4 species on the surface will be established (VLA5 overproducing cells are already available). These experiments will analyze the common and specific mechanisms of VLA3- 5/ligand interaction. Peptides which modify these interactions might modulate the targeting and function of lymphocytes, monocytes and other cells involved in the pathogenesis of the immunologic diseases.