摘要目的观察并比较小鼠树突状细胞(DC)和巨噬细胞对外源性抗原的内吞路径的差异。方法将小鼠骨髓DC和腹腔巨噬细胞与辣根过氧化物酶(HRP)-5 nm胶体金共孵育10分钟后再培养0～120分钟，进行酸性磷酸酶细胞化学反应和组织相容性抗原(MHC)Ⅱ免疫胶体金标记，最后在电镜下观察5 nm胶体金的细胞内运行路径。结果 DC内吞HRP-5 nm胶体金10分钟后再培养30分钟，大部分5 nm胶体金进入MHC Ⅱ隔室(MⅡC)中，只有极少数酸性磷酸酶阳性的溶酶体内含少量5 nm胶体金。而与DC显著不同的是巨噬细胞摄入的大部分5 nm胶体金进入了溶酶体，还有部分5 nm胶体金进入MⅡC中。内吞后再培养60分钟，DC内仍有许多5 nm胶体金，而巨噬细胞内已很少见到5 nm胶体金。结论同一种外源性抗原被DC和巨噬细胞内吞后，在这两类细胞中的运行路径明显不同。内吞后30分钟，巨噬细胞摄入的大部分抗原进入溶酶体，而DC则将大部分抗原送入MⅡC，这可能与DC独特的抗原提呈功能有关。另外，巨噬细胞对抗原的清除能力比DC强得多。

abstractsObjective　To compare the endocytic routes of exogenous antigen between murine dendritic cells (DCs) and macrophages (Mφs).Methods　Murine bone marrow-derived DCs and peritoneal Mφs were pulsed with horseradish peroxidase (HRP)-5 nm colloidal gold for 10 minutes, then grouped and chased for 0-120 minutes in culture medium. Intracellular distribution of 5 nm colloidal gold was explored by means of the cellular enzymatic-chemistry of acid phosphatase and MHC Ⅱ immuno-cytochemistry under electron microscope. Results　After 10 minutes of pulse with HRP-5 nm colloidal gold and 30 minutes of chase, most HRP-5 nm gold particles internalized by DCs entered into MHC class Ⅱ compartments (MⅡCs), and a small portion entered into acid phosphatase-positive lysosomes. In contrast to DCs, most Mφs lysosomes were accessed by HRP-5 nm gold particles, and a small portion of HRP-5 nm gold particles entered into MⅡCs. After 60 minutes of chase, 5 nm gold particles could hardly be seen within Mφs, whereas most 5 nm gold particles were still retained in DCs. Conclusions　The endocytic route of exogenous antigen in DCs seems to be different from that in Mφs. Antigens taken by Mφs mainly enter into lysosomes within 30 minutes. In the case of DCs, most internalized antigens enter into MⅡCs, which may be related to their unique antigen-presenting function . In addition, Mφs seem to have more powerful capacity to scavenge exogenous antigen than DCs.