中文摘要：

目的探讨甘露聚糖结合凝集素（mannan-bindinglectin，MBL）对肽聚糖（peptidogly—can，PGN）刺激佛波酯（PMA）活化的THP-1／CD14细胞产生TNF—α和IL-6影响。方法用PMA活化THP-1／CD14细胞，以不同浓度人MBL预处理2b后再用PGN刺激24h。收集培养上清，以ELISA从蛋白水平分析TNF-α和IL-6的产生。收集细胞提取总RNA，以RT—PCR从转录水平评估TNF—α和IL-6的表达。FACS分析MBL与THP-1／CD14细胞的结合，并进一步分析MBL对PGN结合THP-1／CD14细胞的影响，Western blot分析NF-κB的细胞核移位。结果ELISA检测发现，PGN可刺激PMA活化的各THP-1／CD14细胞分泌TNF-α和IL-6，高浓度MBL（10～20mg／L）可抑制PGN诱导细胞分泌TNF—α和IL-6；RT—PCR分析亦显示，MBL（20mg／L）对PGN诱导的TNF—α和IL-6的mRNA表达有不同程度的抑制作用；流式细胞术检测显示MBL能够与THP-1／CD14细胞以Ca^2＋依赖形式结合，PGN可竞争性抑制MBL结合THP-1／CD14细胞。MBL还可通过结合THP-1／CD14竞争性抑制PGN与THP-1／CD14的结合。Western blot分析显示，MBL对PGN诱导的NF—κB细胞核移位有显著的抑制作用。结论MBL通过配体结合抑制PGN诱导的THP-1／CD14细胞产生的细胞反应，提示MBL能够在PGN诱导的炎性反应中起免疫调控作用。

英文摘要：

Objective To investigate the effects of mannan-binding leetin（MBL） on TNF-α pro- duction induced by peptidoglyean （PGN） and its mechanism in human THP-1/CD14 monocytes. Methods The THP-1/CD14 cells were stimulated for 24 h with PGN at the indicated ratios after pretreated with human natural MBL at concentrations ranging from 1 to 20 mg/L for 2 h. The content of TNF-α and IL-6 in culture supernatants were detected by ELISA, and the levels of TNF-α and IL-6 mRNA expressions in these cells were determined by RT-PCR. FACS was used to investigate the interaction of MBL with THP-1/ CD14 cells and the impact of MBL on PGN binding to THP-1/CD14 cells. Western blot was used to detect PGN-induced NF-KB transloeation in THP-1/CD14 cells. Results ELISA showed that secretion of TNF-α and IL-6 from THP-1/CD14 cells could be induced by PGN;The productions of TNF-α and IL-6 by THP-1/ CD14 cells induced with PGN were profoundly inhibited by MBL at higher concentrations （ 10-20 mg/L） but not MBL at lower concentrations （ 1 mg/L）. RT-PCR analysis also indicated that the mRNA expressions of TNF-α and IL-6 in THP-1/CD14 cells were decreased by MBL at higher concentration,compared to the corresponding THP-1/CD14 cells stimulated with PGN only. FACS showed that the binding of MBL to THP-1/ CDI4 ceils was evident in a Ca^2＋-dependent manner. PGN could competitively inhibit the binding of MBL to THP-1/CD14 cells. MBL could competitively inhibit the binding of PGN to THP-1/CD14 cells by binding to THP-1/CD14 ceils directly. Similarly, MBL at higher concentration （20 mg/L） decreased the NF-KB translocation in THP-1/CD14 cells. Conclusion MBL may inhibit TNF-α and IL-6 production induced by PGN in THP-1/CD14 ceils through NF-KB signaling pathways, suggesting that MBL can play some roles in the regulation of PGN-induced inflammatory response.