目的：探究淋巴细胞和肿瘤细胞形成cell-in-cell胞内嵌合结构的特征及意义。方法：以人肝癌细胞株PLC/PRF/5与人外周血单个核细胞（peripheral blood mononuclear cell，PBMC）形成cell-in-cell胞内嵌合结构为研究模型，采用流式细胞术分析淋巴细胞钻入肿瘤细胞形成cell-in-cell胞内嵌合结构的特征。利用流式分选技术分选出小鼠脾淋巴细胞与PLC/PRF/5细胞形成的cell-in-cell胞内嵌合结构，利用平板克隆形成实验检测cell-in-cell胞内嵌合结构对PLC/PRF/5细胞生物学行为的影响。结果：4 h和8 h时，以CD3/CD28抗体活化的PBMC对PLC/PRF/5细胞的伸入率分别为（15.75±1.28）%、（13.49±123）%，明显高于未活化PBMC的伸入率\[（10.56±0.57）%,（11.38±0.97）%；P<0.05\]；且活化的PBMC在4 h时的伸入率明显高于未活化PBMC在8 h时的伸入率（P<0.05）。小鼠脾淋巴细胞伸入PLC/PRF/5细胞形成cell-in-cell胞内嵌合结构后，PLC/PRF/5细胞的克隆形成率明显高于未形成cell-in-cell胞内嵌合结构的PLC/PRF/5细胞\[（32.25±2.32）% vs（2192±2.02）%，P<0.05\]。结论: 活化后PBMC伸入PLC/PRF/5细胞形成cell-in-cell胞内嵌合结构的比率升高、时间提前，同时形成胞内嵌合结构的肿瘤细胞在体外克隆形成能力增强。

Objective:To study the characterization of the cell-in-cell structure formed between heterotypic cells and its biological significance. Methods:By establishing flow cytometry-based analysis and sorting methodology, the formation of heterotypic cell-in-cell structures between human liver cancer PLC/PRF/5 cells and peripheral blood mononuclear cells (PBMCs) was characterized. Based on this step, a method of sorting the cell-in-cell structures and obtaining the cell-in-cell structures formed between mouse splenocytes and PLC/PRF/5 cells was established. Further analysis of the biological characteristic changes of the PLC/PRF/5 cells via plate colony formation assay showed the effect of the cell-in-cell structure formation on PLC/PRF/5 cells. Results: At 4 h and 8 h, the ratio of the cell-in-cell structures formed by activated PBMCs to PLC/PRF/5 tumor cells were apparently higher than that in the inactivated PBMC group (4 h:\[15.75±128\]% vs \[10.56±0.57\]%, P<0.05; 8 h: \[13.49±1.23\]% vs \[11.38±0.97\]%, P<0.05). Besides, the ratio of activated PBMC group at 4 h was still significantly higher than that in the inactivated PBMC group at 8 h (P<005). The colony formation ratio of the sorted cell-in-cell structures formed by mouse splenocytes into PLC/PRF/5 cells was significantly higher than that of PLC/PRF/5 cells (\[32.25±2.32\]% vs \[21.92±2.02\]%, P<0.05). Conclusion: The ratio of cell-in-cell structures formed between activated PBMCs and PLC/PRF/5 cells is higher than that of the inactivated PBMCs, reaching the highest ratio in shorter time. Meanwhile, tumor cells in cell-in-cell structures show an increased colony formation ability in vitro.

上海市科委基金资助项目（No. 10JC1401200）