Saiki T, Ezaki T, Ogawa M, Maeda K, Yagita H, Matsuno K
Departments of. Anatomy II and. Surgery II, Kumamoto University School of Medicine, Kumamoto 860-0811, Japan.
J Leukoc Biol. 2001 May;69(5):705-12.
Possible roles of dendritic cells (DCs) in allogeneic immune responses in host lymphoid tissues were characterized in situ by using rat DC transfer and cardiac transplantation models. When allogeneic DCs were intravenously injected, these cells selectively migrated to the T-cell area of hepatic lymph nodes, with peak accumulation at 18 h after injection. Donor DCs and proliferating host T cells formed clusters (rosettes) in which the T-cell proliferative response started. The donor DCs were CD80(+) CD86(+) and, ultrastructurally, were in intimate contact with lymphoblasts within the rosettes. As a novel finding, some of the migrated donor DCs were quickly phagocytosed by putative host interdigitating DCS: By 48 h, the remaining donor DCs had disintegrated within the rosettes. Host interdigitating DCs also formed rosettes throughout the T-cell area, and their kinetics correlated well with that of the T-cell proliferation. In the cardiac allograft model, a few donor DCs selectively migrated to the host spleen and hepatic nodes. Rosette formation by donor and host DCs, phagocytosis of donor DCs, and the T-cell proliferative response occurred in much the same fashion as they did in the first experiment. We conclude that the donor rosettes at the early stage represent the sites of direct allosensitization and those at the late stage represent donor-DC killing. Host rosettes are the sites of T-cell proliferation. In this structure, phagocytosed donor-DC-derived antigens are presumably indirectly presented.
通过使用大鼠树突状细胞（DC）转移和心脏移植模型，在原位对宿主淋巴组织中DC在同种异体免疫反应中的可能作用进行了表征。当静脉注射同种异体DC时，这些细胞选择性地迁移至肝淋巴结的T细胞区，注射后18小时积累达到峰值。供体DC与增殖的宿主T细胞形成簇（玫瑰花结），T细胞增殖反应在其中启动。供体DC为CD80(+) CD86(+)，超微结构显示其与玫瑰花结内的淋巴母细胞紧密接触。作为一项新发现，一些迁移的供体DC被假定的宿主交错DC迅速吞噬：到48小时时，剩余的供体DC在玫瑰花结内解体。宿主交错DC也在整个T细胞区形成玫瑰花结，其动力学与T细胞增殖的动力学密切相关。在心脏同种异体移植模型中，少数供体DC选择性地迁移至宿主脾脏和肝淋巴结。供体和宿主DC形成玫瑰花结、供体DC的吞噬作用以及T细胞增殖反应的发生方式与第一个实验大致相同。我们得出结论，早期的供体玫瑰花结代表直接同种异体致敏的部位，晚期的代表供体DC被杀伤的部位。宿主玫瑰花结是T细胞增殖的部位。在这种结构中，吞噬的供体DC衍生抗原可能被间接呈递。
