为研究伤寒沙门菌质粒pR_ST98对人巨噬细胞THP-1自噬过程的影响，以携带伤寒沙门菌质粒pR_ST98的野生株ST6、消除pR_ST98的突变株ST6-ΔpR_ST98和将pR_ST98经接合转移的回补株ST6-c-pR_ST98为受试菌，与THP-1共培养建立感染模型，并加入自噬作用阻断剂氯喹（CQ）进行干预。首先测定CQ单独作用对细胞及细菌的影响，确定CQ最适浓度；在细菌和细胞共作用后的不同时间点收集细胞，通过蛋白免疫印迹法(WB)和mRFP-GFP-LC3 质粒转染法检测细胞LC3Ⅱ蛋白、p62蛋白、自噬体及自噬溶酶体的变化。结果显示，30 μmol/L CQ对细胞自噬的阻断效果明显，且细胞存活率超过50%，对细菌也无明显影响。WB结果显示，用该浓度CQ干预后，ST6-ΔpR_ST98感染组细胞的LC3Ⅱ及p62表达量上升程度显著高于野生株ST6及回补株ST6-c-pR_ST98；CQ干预组3株受试菌感染细胞LC3点状结构数量均高于未加CQ组，且ST6-ΔpR_ST98感染细胞的点状结构数量明显增加。以上结果提示，伤寒沙门菌质粒pR_ST98在自噬前期发挥作用，早于溶酶体降解的过程。

In the present study, the influence of Salmonella enterica serovar Typhi (S. typhi) plasmid pRST98 on autophagy of human-derived macrophage-like cell line THP-1 was investigated. THP-1 cells were infected with wild type strain (ST6), mutant strain (ST6-ΔpR_ST98) and ST6-ΔpR_ST98 with a complemented plasmid encoding pR_ST98 (ST6-c-pR_ST98), and the lysosomotropic agent chloroquine (CQ) was added for intervention. First, the appropriate concentration of CQ was determinated by detecting the influence of CQ on cells and bacteria respectively. The cells were collected at different time points after cocultivation with bacteria. The changes of protein LC3Ⅱ, p62, autophagosome and autolysosomes were detected by Western blotting and monomeric red fluorescent protein-green fluorescent protein (mRFP-GFP)-LC3 plasmid transfection. The results revealed that 30 μmol/L CQ could significantly block the autophagic process, and had no obvious influence on the cells and bacteria. The Western blotting analysis showed that the augment of autophagy protein LC3Ⅱ and p62 in ST6-ΔpR_ST98 group was higher than those in ST6 and ST6-c-pR_ST98 groups after CQ treatment. Similarly, the LC3 dots in the groups treated with CQ were higher than those in the groups without CQ treatment. Specifically, even more remarkable level of LC3 dots in ST6-ΔpR_ST98 group than that in the wild type group was observed. All these evidences suggested that S. typhi plasmid pR_ST98 works in the early stage of autophagy, prior to degradation in autolysosomes.