Distinction of skin homing T cells that bind P-selectin

描述(申请人提供)：T细胞在许多炎症性和特定的恶性皮肤病中起致病作用。皮肤淋巴细胞相关抗原(CLA)区分人类T细胞，选择性地定位于皮肤。CLA是一种sialyI-Lewis x相关的碳水化合物，它的检测表明，血管黏附分子E-选择素和P-选择素的碳水化合物配体的生物合成所必需的某些糖基转移酶的表达。然而，E-选择素和P-选择素在T细胞上识别的碳水化合物结构并不相同。E-选择素碳水化合物配体的生物合成需要α，3-岩藻糖基转移酶-VII(FUCT-VII)，而P-选择素碳水化合物配体需要FUCT-VII和糖链分支酶核心2β-1，6-乙酰氨基葡萄糖转移酶(C2GnT)。重要的是，这些酶在T细胞分化过程中受到不同信号的调节，这可能导致效应性T细胞表达E-和/或P-选择素的碳水化合物配体的极化。CLA的一个局限性是其生物合成不需要C2GnT，因此它的检测不能直接指示P-选择素碳水化合物配体的表达，也不能区分E-选择素和P-选择素结合的T细胞亚群。我们已经鉴定了一种新型的mAb(CHO-131)，它需要同时表达Fuct-Vll和C2GnT来进行反应，并且当以sialyI-Lewis x终止时选择性地识别核心20-糖链。这个碳水化合物基序已经被直接证明可以与P-选择素高亲和力结合。CHO-131对代表CLA*T细胞亚群的效应/记忆淋巴细胞群进行染色。这些发现提供了重要的新证据，表明CLA*T细胞可能是由与E-选择素和P-选择素差异结合的亚群组成的混合群体。我们假设CHO-131“T细胞优先表达P-选择素的高亲和力碳水化合物配体，并浸润性T细胞介导的皮肤病变。我们的第一个目标是比较CHO-131*/CLA*和CHO-131/CLA*T细胞的E-和P-选择素结合能力。第二个目标是确定CHO-131”T细胞和CLA*T细胞在各种T细胞介导的皮肤病中的渗透水平。这项拟议研究的基本原理是，如果能够理解和操纵T细胞向皮肤运输的成分、机制和调节，预防性和治疗性T细胞治疗可能会得到优化。

DESCRIPTION (provided by applicant): T cells play a pathogenic role in many inflammatory and particular malignant skin diseases. The cutaneous lymphocyte-associated antigen (CLA) distinguishes human T cells that selectively home to the skin. CLA is a sialyI-Lewis x-related carbohydrate and its detection indicates the expression of certain glycosyltransferases necessary for the biosynthesis of carbohydrate ligands for the vascular adhesion molecules E-selectin and P-selectin. However, the carbohydrate structures recognized by E- and P-selectin on T cells are not identical. The biosynthesis of E-selectin carbohydrate ligands requires the enzyme al,3- fucosyltransferase-VII (FucT-VII), whereas P-selectin carbohydrate ligands require both FucT-VII and the Oglycan branching enzyme core 2 beta1,6 N-acetylglucosaminyltransferase (C2GnT). Importantly, these enzymes are regulated by different signals during T cell differentiation, which may result in effector T cells polarized in their expression of carbohydrate ligands for E-, P-selectin, or both. A limitation of CLA is that its biosynthesis does not require C2GnT and so its detection would not directly indicate the expression of Pselectin carbohydrate ligands nor would this phenotypic marker distinguish E- vs. P-selectin binding T cell subsets. We have characterized a novel mAb (CHO-131) that requires the expression of both FucT-Vll and C2GnT for reactivity and selectively recognizes a core 20-glycan when terminated with sialyI-Lewis x. This carbohydrate motif has been directly shown to confer high-affinity binding by P-selectin. CHO-131 stains a population of effector/memory lymphocytes that represent a subset of CLA* T cells. These findings provide important new evidence that CLA* T cells may be a mixed population consisting of subsets that differentially bind to E- and P-selectin. We hypothesize that CHO-131" T cells preferentially express high affinity carbohydrate ligands for P-selectin and infiltrate T cell-mediated skin lesions. Our first objective is to compare the E- and P-selectin binding capacity of CHO-131*/CLA* and CHO-131/CLA* T cells. Our second objective is to determine the level of infiltration by CHO-131" T cells and CLA* T cells in various T cellmediated skin diseases. The rationale for the proposed study is that preventative and therapeutic T cellbased treatments may be optimized if the components, mechanisms, and regulation of T cell trafficking to the skin can be understood and manipulated.