LYMPHOCYTE RECRUITMENT BY VASCULAR ADHESION MOLECULES

淋巴细胞归巢到炎症部位是由血管内皮细胞上的黏附分子与淋巴细胞表面的配体之间的相互作用引导的。携带适当配体的淋巴细胞归巢到特定器官可能是由血管黏附分子的选择性表达决定的。我的假设是，皮肤微血管内皮细胞具有黏附分子E-选择素、VCAM-1和ICAM-1的特征性表达，其不同于其他组织，是细胞因子反应和黏附分子表达持续时间的函数。我将确定内皮细胞黏附分子表达的这些组织特异性差异是否会导致携带特定黏附分子配体的淋巴细胞亚群的选择性招募。这将通过1)构建嵌合的人类免疫缺陷小鼠模型，在该模型中比较人淋巴细胞与来自皮肤、肺、皮下脂肪和脐静脉的内皮细胞之间的相互作用；2)系统地表征体外(器官和细胞培养)和体内对细胞因子刺激的黏附分子表达的组织特异性差异；3)确定是否需要特定的黏附分子组合来在体内招募特定的T细胞亚群，首先将完全或异基因反应的人PBMC接种嵌合动物，然后使用阻断抗体选择性地干扰黏附分子-配体的相互作用；4)在没有其他差异的情况下，通过逆转录病毒转导改变内皮细胞黏附分子的表达谱，确定这些相互作用是否足以选择性地招募淋巴细胞，并评估其对浸润性T细胞表型的影响。一项为期五年的指导计划被提出，以检验这一假设。该计划将包括免疫学和分子生物学领域的培训，培训由一位在免疫生物学和血管生物学方面具有良好背景的导师(J.Pober)、一位具有分子生物学专业知识的合作者(A.Bothwell和M.Kluger)以及许多课程和研讨会指导。在这一阶段结束时，我的目标是成为一名独立的研究员，并为理解皮肤淋巴细胞募集做出贡献，这可以用于开发在皮肤中具有特定活性的抗炎剂。

Lymphocyte homing to sites of inflammation is directed by the interaction between adhesion molecules on the vascular endothelium and their ligands on the surface of the lymphocytes. The homing of lymphocytes bearing the proper ligands to specific organs may be determined by the selective expression of vascular adhesion molecules. It is my hypothesis that the microvascular endothelium of the skin has a characteristic profile expression of the adhesion molecules E-Selectin, VCAM-1, and ICAM-1 that differs from other tissues as a function of cytokine responsiveness and duration of adhesion molecule expression. I will determine whether these tissue specific differences in endothelial adhesion molecule expression result in the selective recruitment of subsets of lymphocytes bearing specific adhesion molecule ligands. This will be accomplished by 1) constructing a chimeric human-immunodeficient mouse model in which to compare the interactions between human lymphocytes and endothelial cells derived from skin, lung, subcutaneous fat and umbilical vein; 2) systematically characterizing tissue specific differences in adhesion molecule expression in response to cytokine stimulation in vitro (in both organ and cell culture) and in vivo; 3) determining whether specific combinations of adhesion molecules are necessary for the recruitment of specific T cell subsets in vivo by first inoculating the chimeric animals with whole or alloreactive cell depleted human PBMC, then using blocking antibodies to selectively interfere with adhesion molecule-ligand interactions; 4) determining whether these interactions are sufficient, in the absence of other differences, for selective lymphocyte recruitment by using retroviral transduction to alter the repertoire of endothelial adhesion molecule expression, and assessing the effect on the phenotype of infiltrating T-cells. A five year mentored program is proposed test this hypothesis. This program will incorporate training in the fields of immunology and molecular biology under the guidance of a mentor (J. Pober) with a well established background in immunobiology and vascular biology, collaborators (A. Bothwell and M. Kluger) with expertise in molecular biology, as well as from numerous courses and seminars. At the end of this period it is my goal to be well established as an independent investigator, and to have made a contribution to the understanding of cutaneous lymphocyte recruitment which could be exploited in the development of anti inflammatory agents with specific activity in the skin.