XENOGENEIC MODEL FOR HOMING OF HUMAN LYMPHOCYTES

战略提出了评估的潜力，严重结合 免疫缺陷（SCID）小鼠作为体内模型来研究 参与人类淋巴细胞归巢的机制。 淋巴细胞 迁移到外周淋巴结是由以下物质的相互作用引发的： 淋巴细胞上的L-选择素归巢受体与血管地址素 毛细血管后高内皮微静脉（HEV）。 以确定是否 地址素表达在免疫缺陷小鼠中正常发展， 将进行外周淋巴结水平的比较 地址素在正常Balb/c和SCID小鼠HEV上的表达。 MECA-79 单克隆抗体，其结合鼠和人外周血 淋巴结血管地址素，将用于检测是否存在 通过免疫组织化学染色和蛋白质印迹分析该抗原。 还提出了实验来确定鼠SCID外周血淋巴细胞是否 淋巴结HEV在功能上能够介导L-选择素依赖性 人淋巴细胞的粘附。 这一目标将通过以下方式实现：（a） 直接比较体外人淋巴细胞与外周淋巴细胞的结合 正常BalB/c和SCID小鼠的结HEV和（B）检查 L-选择素特异性阻断抗体对人巨噬细胞粘附的影响 淋巴细胞对鼠HEV的反应。 非阻断性L-选择素特异性单克隆抗体 将抗体用作阴性对照。 此外，协议 旨在评估L-选择素依赖的人淋巴细胞归巢 SCID小鼠的外周淋巴结。 这一目标将是 通过检查异种输血的人的组织定位来完成 淋巴细胞表达高或低水平的L-选择素外周 淋巴结归巢受体 L-选择素在淋巴细胞归巢中的作用 介导人淋巴细胞向外周淋巴定位的受体 淋巴结将通过用L- 在异种输血到SCID中之前的选择素特异性阻断抗体 小鼠 成功开发研究人类归巢的体内模型 将代表多学科的重大进步。 这种模式的 提供了一个独特的系统，在其中探索L-选择素的作用， 以及正常淋巴细胞归巢中的其他粘附途径， 病理过程如炎症和转移。 此外，委员会认为， 这个模型应该被证明对评估新的治疗策略有用 在这些病理性疾病中。

Strategies are proposed to evaluate the potential of severe combined immunodeficient (SCID) mice to serve as an in vivo model to study mechanisms involved in homing of human lymphocytes. Lymphocyte migration into peripheral lymph nodes is initiated by the interaction of the L-selectin homing receptor on lymphocytes with the vascular addressin on post-capillary high endothelial venules (HEV). To determine if addressin expression develops normally in immunodeficient mice, a direct comparison will be performed of the level of the peripheral lymph node addressin expressed on HEV of normal Balb/c and SCID. The MECA-79 monoclonal antibody, which binds to both the murine and human peripheral lymph node vascular addressin, will be used to detect the presence of this antigen by immunohistochemical staining and Western blot analysis. Experiments are also proposed to determine if murine SCID peripheral lymph node HEV are functionally capable of mediating L-selectin-dependent adhesion of human lymphocytes. This aim will be accomplished by (a) directly comparing human lymphocyte binding in vitro to peripheral lymph node HEV of normal Balb/c and SCID mice and (b) examining the effect of L-selectin-specific blocking antibodies on the adhesion of human lymphocytes to murine HEV. Non-blocking L-selectin-specific monoclonal antibodies will be used as a negative control. In addition, protocols are designed to evaluate L-selectin-dependent homing of human lymphocytes to peripheral lymph nodes of SCID mice in vivo. This aim will be accomplished by examining the tissue localization of xenotransfused human lymphocytes that express high or low levels of the L-selectin peripheral lymph node homing receptor. The role of the L-selectin lymphocyte homing receptor in mediating human lymphocyte localization to peripheral lymph nodes will be further determined by treating human lymphocytes with L- selectin-specific blocking antibodies prior to xenotransfusion into SCID mice. Successful development of an in vivo model to study human homing will represent a major advance to multiple disciplines. This model will provide a unique system in which to explore the role of L-selectin as well as other adhesion pathways in normal lymphocyte homing and in pathological processes such as inflammation and metastasis. Moreover, this model should prove useful for evaluating new therapeutic strategies in these pathological disorders.