67 KD LAMININ BINDING PROTEIN ON HUMAN T LYMPHOCYTES

T细胞与基底膜的主要糖蛋白层粘连蛋白的相互作用对炎症反应很重要。然而，淋巴细胞表面受体与层粘连蛋白的相互作用才刚刚开始被理解。 对活化T细胞中表达的基因的搜索显示，非整合素，67 kD层粘连蛋白结合蛋白（p67 LBP）在活化外周血T细胞的亚群（10- 15%）的表面上表达。 表面p67 LBP表达可通过FACS使用抗p67 LBP mAb MLuC 5在用PDB和离子霉素活化T细胞的6小时内检测到，在活化后24小时达到峰值，并持续7-10天。 表达p67 LBP的T细胞亚群是记忆细胞表型（100%CD45 RO+/CD 45 RA-）的成熟的单阳性细胞（85%CD4 +/8-，15%CD4-/8+）。 p67 LBP+ T细胞还表达整合素α 6链（CD 49 f），已知其与肿瘤细胞上的p67 LBP相关。 此外，p67 LBP+ T细胞表达整合素β 1，其与层粘连蛋白特异性整合素受体VLA-6（α 6 β 1）中的α 6相关。 编码37 kD LBP前体（p37 LBPP）的外源cDNA的表达赋予p67 LBP在p67 LBP阴性Jurkat T细胞系（B2.7）上的表面表达。p67 LBP的表达诱导B2.7转染子粘附于层粘连蛋白，但亲合的层粘连蛋白结合依赖于高水平VLA-6的共表达。 总之，这些数据表明，p67 LBP是记忆T细胞上的活化诱导的表面结构，其与VLA-6一起介导细胞粘附层粘连蛋白。 我们拟研究p67 LBP在正常人T细胞和Jurkat T细胞系上的表达，以解决以下具体目标：（1）什么样的刺激诱导p67 LBP在正常T细胞上的表达？(2)p67 LBP的结构是什么？(3)p67 LBP和整合素α 6对淋巴细胞层粘连蛋白特异性粘附的作用是什么？以及（4）p67 LBP和α 6对层粘连蛋白介导的板足形成、运动和跨内皮迁移的贡献是什么？

T cell interactions with laminin, the major glycoprotein of basement membranes, are important to the inflammatory response. However, the interactions of lymphocyte surface receptors with laminin are only beginning to be understood. A search for genes expressed in activated T cells revealed that the non-integrin, 67 kD laminin binding protein (p67 LBP) is expressed on the surface of a subset (10-15 percent) of activated peripheral blood T cells. Surface p67 LBP expression is detectable by FACS using the anti-p67 LBP mAb, MLuC5, within 6 h of T cell activation with PDB and ionomycin, peaks 24 h post-activation, and persists for 7-10 days. The subset of T cells expressing p67 LBP are mature, single-positive cells (85 percent CD4+/8-, 15 percent CD4-/8+) of memory cell phenotype (100 percent CD45 RO+/CD45 RA-). The p67 LBP+ T cells also express the integrin alpha6 chain (CD49f), which is known to associate with p67 LBP on tumor cells. In addition, the p67 LBP+ T cells express the integrin beta1, which associates with alpha6 in the laminin-specific integrin receptor VLA-6 (alpha6beta1). Expression of an exogenous cDNA encoding the 37 kD LBP precursor (p37 LBPP) confers p67 LBP surface expression on a p67 LBP-negative Jurkat T cell line (B2.7). Expression of p67 LBP induces B2.7 transfectants to adhere to laminin, but avid laminin binding depends on co-expression of high level VLA-6. Taken together, these data indicate that p67 LBP is an activation-induced surface structure on memory T cells that, together with VLA-6, mediates cellular adherence to laminin. We propose to study p67 LBP on normal human T cells and on the Jurkat T cell line in order to address the following specific aims: (1) What stimuli induce the expression of p67 LBP on normal T cells? (2) What is the structure of p67 LBP? (3) What are the contributions of p67 LBP and the integrin alpha6 to lymphocyte laminin-specific adherence? and (4) What are the contributions of p67 LBP and alpha6 to laminin-mediated lamellipod formation, locomotion, and transendothelial migration?