Dendritic Cell Dynamics in the Liver and Hepatic Lymph

(1)大鼠肝脏间质树突状细胞(DC)周转约2~3wk。肝内DC(间质DC)捕获和处理抗原，进入引流淋巴(肝淋巴中的DC)，并聚集在肝淋巴结的T细胞区(参考文献1)。(2)静脉注射乳胶(大鼠，REF.2)或痤疮杆菌(小鼠，REF，4，8)后，DC前体可被募集到肝脏。(3)静脉注射DC后，DC很快出现在肝脏，并在汇管区的血窦中突然停滞。这些DC主要结合到Kupffer细胞上，然后在4小时后转移到门脉区域(参考文献)。(4)DC前体和处于抗原转运阶段的DC都可被募集到肝脏，并且它们的大多数最初通过N-乙酰半乳糖胺特异性的C型凝集素样受体(REF.2，3)与Kupffer细胞选择性结合。(5)同种异体肝移植后宿主淋巴组织中的供体MHCII+细胞具有未成熟的DC表型，可能对应于肝脏中的大鼠DC前体细胞(准备中)。(7)静脉注射同种异体DC或心脏移植时，供体DC在T细胞增殖反应开始的肝脏淋巴结中与增殖的宿主T淋巴母细胞(玫瑰花结)形成簇(REF.5，6)。综上所述，肝脏中的DC系统高度精细，与免疫系统紧密相连，不仅有助于局部防御，也有助于全身宿主对血液传播抗原的防御。

(1) Turnover of interstitial dendritic cells (DC) in the rat liver is in the order of 2-3 wk. DC in the liver (interstitial DC) capture and process antigens, enter the draining lymph (DC in hepatic lymph) and accumulate in the T cell area of hepatic lymph nodes (REFERENCE 1).(2) DC precursors could be recruited to the liver after intravenous injection of latex (rats, REF.2) or P. acnes bacilli (mice, REF.4,8).(3) Intravenously injected DC soon appeared in the liver and displayed a sudden arrest in sinusoids in periportal regions. These DC mostly bound to Kupffer cells and then moved to the portal area by 4 hr (REF. 2,9).(4) Both DC precursors and DCs at the antigen-transporting stage could be recruited to the liver and their majority initially showed a selective binding to Kupffer cells through N-acetylgalactosamine-specific C-type lectin-like receptors (REF.2, 3).(5) Donor MHCII+ cells in host lymphoid tissues after liver allotransplantation have a phenotype of immature DC and may correspond to rat DC progenitors in the liver (in preparation).(7) When allogeneic DCs were intravenously injected, or heart graft was transplanted, donor DCs formed clusters with proliferating host T lymphoblasts (rosettes) in hepatic lymph nodes where the T-cell proliferative response started (REF.5, 6).In summary, DC system in the liver is highly elaborated and tightly connected to the immune system, contributing to not only local defense but also systemic host defense to blood-borne antigens.