Phagocytosis of apoptotic cells by macrophages from NOD mice is reduced

Macrophages limit inflammatory responses by clearing apoptotic cells. Deficiencies in apoptotic cell phagocytosis have been linked to autoimmunity. In this study, we determined the efficiency with which macrophages from diabetes-prone NOD and diabetes-resistant NOR, Idd5, Balb/c, and C57BL/6 mice phagocytose apoptotic thymocytes and NIT-1 insulinoma cells. Peritoneal and bone marrow-derived macrophages from NOD mice engulfed fewer apoptotic thymocytes than macrophages from Balb/c mice (P < 0.05). Peritoneal macrophages from NOR and Idd5 NOD congenic mice were more proficient at engulfment than their NOD counterparts. Annexin V blockade diminished apoptotic thymocyte clearance and heat-labile serum factors augmented clearance. Binding of apoptotic thymocytes to NOD macrophages was also reduced, suggesting that the deficiency in phagocytosis may be partly attributable to a recognition defect. Peritoneal macrophages from female Balb/c and NOD mice were equally efficient in the engulfment of microspheres, suggesting that the phagocytic deficiency observed in NOD mice was specific for apoptotic cells. In summary, we have demonstrated a deficiency in phagocytic function of macrophages from NOD mice. Normal and diabetes-prone neonatal rodents have a wave of beta-cell apoptosis coincident with the onset of target organ inflammation. A constitutive defect in the clearance of apoptotic beta-cells may be contributory to the initiation of autoimmunity.     

脾脏树突状细胞在全身性感染中的变化及治疗意义

背景 全身性感染是临床危重症患者死亡的主要原因之一,近年研究显示免疫功能紊乱与全身性感染发生发展密切相关,全身性感染病程中机体免疫功能紊乱与脾脏树突状细胞(dendritic cell,DC)的变化关系密切.目的 探讨脾脏DC在全身性感染中的变化及其意义,为改善全身性感染预后提供新思路.内容 在全身性感染病程中,脾脏DC大量丢失,细胞因子表达谱也发生明显改变,并与不良预后相关.增加DC数量可以改善预后.趋向 全身性感染病程中,脾脏DC数量和功能呈动态改变,并参与其发生发展,以脾脏DC为靶点调控其病程提供了新的防治前景.     

脾脏树突状细胞在全身性感染中的变化及治疗意义

背景 全身性感染是临床危重症患者死亡的主要原因之一,近年研究显示免疫功能紊乱与全身性感染发生发展密切相关,全身性感染病程中机体免疫功能紊乱与脾脏树突状细胞(dendritic cell,DC)的变化关系密切.目的 探讨脾脏DC在全身性感染中的变化及其意义,为改善全身性感染预后提供新思路.内容 在全身性感染病程中,脾脏D...     

Site of splenic autotransplantation affects protection from sepsis

Using an animal model with bacteria delivered through the respiratory tract, the relative protective effects of subcutaneous and intraperitoneal splenic autotransplants were compared. Animals with intraperitoneal implants demonstrated a mortality not different from that in control animals and an early mortality significantly lower than found in splenectomized animals. Subcutaneous splenic autotransplantation provided no protective effect. The inability of extraperitoneal subcutaneous implants to protect against postsplenectomy pulmonary sepsis in our model suggests that subcutaneous splenic autotransplantation is an inappropriate alternative to intraperitoneal splenic autotransplantation in the clinical setting.     

Regulatory dendritic cells modulate immune responses via induction of T-cell apoptotic death

We describe a regulatory lymphoid dendritic cell (LDC) population propagated from mouse liver nonparenchymal cells (NPC) in IL-3 and anti-CD40 monoclonal antibody that are phenotypically mature, and induce T-cell hyporesponsiveness by promoting T-cell apoptotic death, which is partially caspase-dependent, but is unlikely to be mediated by soluble factor(s). In vivo administration of liver LDC significantly prolonged the survival of vascularized cardiac allografts in an alloantigen-specific manner. This is associated with enhanced T-cell death in secondary lymphoid organs.     

丙戊酸钠增强免疫细胞对人膀胱癌细胞的杀伤作用

目的:探讨丙戊酸钠(VPA)对膀胱癌细胞MICA表达的影响以及所产生的肿瘤免疫作用,以期为防治膀胱癌复发和浸润提供新的治疗方法。方法:采用不同浓度VPA处理人膀胱尿路上皮癌T24细胞后,用半定量RT-PCR和流式细胞术检测癌细胞中MICA mRNA和蛋白表达。用乳酸脱氢酶法检测外周血单个核细胞(PBMCs)对经VPA处理的T24细胞的杀伤作用。结果:VPA从mRNA和蛋白水平诱导T24细胞表达MICA,并增强T24细胞对PBMCs细胞毒作用的敏感性。结论:VPA能增强膀胱癌对免疫细胞杀伤作用的敏感性,可作为防治膀胱癌的辅助药物。     

人参二醇组皂苷增强顺铂对人前列腺癌DU145细胞凋亡的效应

目的 探讨人参二醇组皂苷(panoxadiol saponin PDS)与顺铂(cisplatin,DDP)联合应用对DU145前列腺癌细胞增殖及凋亡的影响.方法 采用MTT比色法检测PDS与DDP联合应用对DUl45细胞增殖活力的影响;吖啶橙染色观察诱导细胞凋亡情况;流式细胞仪分析细胞周期及凋亡,并计算细胞平均凋亡率;免疫化学和Western blot技术观察细胞内激活的caspase3的表达.结果 100mg/L,PDS与0.2 u mol/L DDP联合给药:(1)48h后可使单独应用0.2 1.tmol/L DDP组其肿瘤细胞生长抑制率由16.35%提高到47.13%;(2)吖啶橙荧光染色可见细胞呈现明显凋亡形态,其凋亡率与2μmol/L DDP组相当:(3)流式细胞术结果显示,可使单独应用0.2μmol/L DDP组其诱导DU145细胞凋亡率从5.53%提高到19.39%,相当于其10倍剂量即2.0 μmol/L DDP的诱导凋亡效应(21.05%),明显高于PDS单独应用的凋亡率:(4)免疫化学和Western blot结果显示,可使单独应用O.2 μmol/L DDP组细胞内激活的caspase3阳性细胞率与2 μmol/L DDP组相当.结论 PDS能增强DDP对DU145前列腺癌细胞的致凋亡效应.     

Basic fibroblast growth factor selectively enhances TNF-alpha-induced apoptotic cell death in glomerular endothelial cells: effects on apoptotic signaling pathways

Endothelial cell damage of glomeruli and kidney arterioles seems to play a pivotal role in several pathologic situations, such as Gram-negative sepsis, glomerulonephritis, and acute renal failure. Bacterial lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha) have been identified as potent inducers of apoptotic cell death in bovine glomerular endothelial cells. Both agents elicited apoptotic DNA laddering within 12 to 24 h. Basic fibroblast growth factor (bFGF) was generally described as a protective factor for endothelial cells against radiation-, TNF-alpha-, and UV-light-induced programmed cell death. Therefore, whether bFGF also affects apoptosis of microvascular endothelial cells was questioned. Surprising was that simultaneous treatment of glomerular endothelial cells with bFGF and either LPS or TNF-alpha left LPS-induced death unaffected, whereas TNF-alpha-induced death induction was potentiated, amounting to 48.9+/-6.3% versus 22.4+/-4.3% DNA degradation with TNF-alpha alone. Comparably, acidic FGF also selectively potentiated TNF-alpha-induced apoptosis. In mechanistic terms, bFGF synergistically increased TNF-alpha-induced mitochondrial permeability transition, the release of cytochrome c from mitochondria to the cytosol, and upregulation of the proapoptotic protein Bak and significantly enhanced activation of caspase-8 protease activity. In contrast, stress-activated protein kinase and nuclear factor kappaB activation, which represent primary signals of TNF/TNF receptor interaction, downregulation of the antiapoptotic protein Bcl-x(L), and caspase-3-like protease activation, were unaffected. As bFGF did not affect LPS-induced apoptotic cell death, bFGF also left LPS-induced Bak upregulation and Bcl-x(L) downregulation unaffected. The results point to a selective bFGF-mediated enhancement of distinct proapoptotic pathways induced by TNF-alpha in glomerular endothelial cells.     

hCD47诱导人巨噬细胞对猪内皮细胞的免疫耐受

目的  探讨人CD47（hCD47）在诱导人巨噬细胞对猪内皮细胞免疫耐受中的作用。方法  将转染了pCDH-hCD47-FLAG质粒的猪髂总动脉内皮细胞（PIEC）设为pCDH-hCD47组;将转染了pCDH-FLAG空载体质粒的PIEC为pCDH组;将转染了hCD47-dN的PIEC设为pCDH-hCD47-dN组;将人脐静脉内皮细胞（HUVEC）设为阳性对照组。将细胞分别与人巨噬细胞共培养,检测信号调节蛋白α（SIRPα）的磷酸化情况以及人巨噬细胞对PIEC的杀伤作用。进一步从GT^－/－及GT^－/－/hCD47基因编辑猪中分离了猪主动脉血管内皮细胞（PAEC）, 并分析SIRPα的磷酸化情况及人巨噬细胞对PAEC的杀伤作用。结果  pCDH组细胞不能诱导SIRPα的磷酸化,而pCDH-hCD47组细胞与人巨噬细胞共培养10 min后便能够激活SIRPα的磷酸化,且随着共培养时间的延长,SIRPα的磷酸化程度也随之增强。pCDH-hCD47-dN组细胞不能激活SIRPα的磷酸化。人巨噬细胞对pCDH组细胞产生了明显的杀伤作用,pCDH-hCD47组细胞可明显抑制人巨噬细胞的杀伤作用（P < 0.05）,而pCDH-hCD47-dN组细胞则不能抑制人巨噬细胞的杀伤作用。GT^－/－-PAEC与人巨噬细胞共培养后,不能激活SIRPα的磷酸化;而GT^－/－/hCD47-PAEC与人巨噬细胞共培养后则明显激活了SIRPα的磷酸化。人巨噬细胞对GT^－/－-PAEC产生了明显的杀伤作用,GT^－/－/hCD47-PAEC可明显抑制人巨噬细胞的杀伤作用（P < 0.05）。结论  在猪内皮细胞中表达hCD47可以通过激活SIRPα的磷酸化抑制人巨噬细胞对内皮细胞的杀伤作用。     

Intraperitoneal splenic implants do not alter clearance of pneumococcal bacteremia

The effect of intraperitoneal splenic autotransplants was studied in Sprague-Dawley rats. Twenty animals underwent total splenectomy. Splenectomy was performed in another group of 20 rats, after which the spleen was diced into 15 pieces and replaced within the leaves of the small bowel mesentery. Twelve weeks later pneumococcal bacteremia was induced by intraperitoneal injection of 5 X 10(6) Streptococcus pneumoniae. Quantitative blood cultures were obtained from the tail vein 15, 30, 45, 60, 90, and 240 minutes after injection. Mean bacterial counts with time for animals bearing splenic autotransplants were not significantly different from completely asplenic rats. At autopsy, all animals receiving splenic implants were found to have viable splenic tissue among the leaves of the small bowel mesentery. This study shows that even allowing 12 weeks for maximal regeneration, splenic autotransplants fail to significantly alter the clearance of an established bacteremia.     

Lymphatic pump treatment enhances the clearance of pneumonia

BackgroundOsteopathic lymphatic pump treatments (LPT) are thought to aid in the removal of metabolic wastes, toxins, exudates, and cellular debris that occur during infection or oedema. In elderly patients with pneumonia LPT decreased hospital stay, length of intravenous antibiotics, and incidence of death when compared to conventional care. In animals, LPT has been reported to enhance the lymphatic and immune systems and facilitate the clearance pneumonia caused by Streptoccocus pneumoniae. The purpose of this study was to determine the number of LPT necessary to enhance the clearance of S. pneumoniae from the lungs and explore the mechanisms associated with this protection.MethodsRats were nasally infected with S. pneumoniae. Twenty-four hours after infection, rats were divided into control sham and LPT groups. For four consecutive days, the control group received no treatment or anaesthesia, the sham group received four min of light touch (under anaesthesia), and the LPT group received four min of LPT (under anaesthesia). On days 1, 3 and 4 post-infection, lungs were removed and measured for S. pneumoniae bacteria and the number of pulmonary leukocytes. Bronchoalveolar lavage fluid (BALF) was collected at day 4 post-infection and analysed for inflammatory mediators, antibacterial factors and alveolar macrophage function.ResultsThree applications of LPT were able to significantly (p < 0.05) reduce the numbers of pulmonary bacteria compared to control and sham. There were no significant differences in lung leukocytes between treatment groups at any time point, suggesting LPT does not enhance the concentration of pulmonary leukocytes. There were also no significant differences in the BALF concentrations of IL-1β, C-reactive protein, TNF-α, and MCP-1 between control, sham or LPT groups at day 4. This was not surprising, since these factors mediate pneumococcal clearance within the first 0–48 h of infection. Of importance, LPT increased the concentration of SP-D, IL-6, IL-17 and IL-12 in the BALF and enhanced the production of NO2- and IL-6 by alveolar macrophages compared to sham and control.ConclusionsWe have shown that three daily LPT enhance the clearance of pneumococcal bacteria, and the concentration of SP-D, IL-6, IL-12 and IL-17 in the BALF. During pneumococcal pneumonia, IL-12 and IL-17 enhance the entry of neutrophils into the lungs, SP-D enhances phagocytosis by neutrophils, and IL-6 delays neutrophil apoptosis and enhances neutrophil cytotoxic function. Alveolar macrophages from LPT treated rats produced more nitric oxide and IL-6 in vitro. Therefore, by enhancing the concentration of immune factors, LPT may preserve neutrophil-mediated clearance of pneumococcus. Collectively, our study supports the clinical use of LPT to treat pneumonia.     

脾脏免疫功能亢进与肝细胞癌的关系

在我国85%～90%的肝癌合并不同程度的肝硬化,约30%合并脾功能亢进.肝癌合并脾功能亢进传统上一般被视为手术禁忌证[1].近年来,随着外科手术技巧的不断提高及围手术期处理日趋完备,该手术切除率有所提高[2],但生存率不理想[3].对肝癌合并脾功能亢进的治疗,有些作者认为行肝癌和脾切除,可减少手术死亡率,延长生存率[4].而有些人认为脾切除增加了手术危险性,降低了病人的免疫力和生存率[5].该文就此问题作一综述.     

Salmonella sepsis following posttraumatic splenectomy and implantation of autologous splenic tissue

A severe complication following implantation of autologous splenic tissue occurred in a 51-year-old man. Indirect injury to abdomen resulted in a lesion of the splenic artery. Following splenectomy and reimplantation of splenic tissue into three pouches, a severe Salmonella sepsis developed within 24 hours. At second look laparotomy two pouches were infected. Recently there had been moderate signs of gastroenteritis and the same bacteria was cultivated from feces. Modifications of the implantation procedure are discussed.     

Preservation of splenic tissue prevents postsplenectomy pulmonary sepsis following bacterial challenge

Previous studies utilizing an intravenous method of bacterial challenge have failed to demonstrate a protective effect of reimplanted splenic tissue. This method of intravenous bacterial challenge bypasses the lungs, the usual portal of entry in postsplenectomy sepsis. In this study a method of bacterial challenge via the lung was used to investigate the ability of splenic tissue to protect against postsplenectomy sepsis. For this purpose 203 rats were divided into four groups: total splenectomy, hemisplenectomy, sham-operated controls, and nonoperated controls. Two weeks postoperatively all rats were challenged with either 1 × 10⁵ or 5 × 10⁶Streptococcus pneumoniae delivered via transtracheal injection. Mortality rates were observed for 2 weeks. At the lower dose of bacteria, no difference in mortality was observed among all treatment groups. Similarly there was no difference in 14-day mortality at the larger bacterial dose. At the higher challenge dose, however, there was a significant difference in early mortality (Days 1–9) between the total splenectomy group (100% mortality) and the other three groups (control 38%, sham control 25%, hemisplenectomy 25%). There was no difference in mortality between the hemisplenectomy group and the two control groups. Unlike the intravenous method of challenge, transtracheal challenge does not bypass the pulmonary host-defense system, thus allowing interaction of splenic-derived tuftsin and antibody with pulmonary-derived neutrophils and macrophages, and provides a more suitable model for the study of postsplenectomy spesis. Splenectomy was shown to result in a higher early mortality due to pulmonary sepsis, whereas preservation of at least half the spleen reduced the early mortality due to pulmonary sepsis.