Phase I clinical trial of O-acetylated pectin conjugate,a plant polysaccharide based typhoid vaccine

Background

Typhoid fever remains an important cause of morbidity and mortality in the developing countries. Vi capsular polysaccharide conjugate vaccine demonstrated safety and efficacy in young children in high endemic regions. A novel typhoid conjugate vaccine based on plant polysaccharide pectin was studied in a phase I trial.

Methods

Fruit pectin, having the same carbohydrate backbone structure as Vi, was purified from citrus peel and used as the polysaccharide source to prepare a semi-synthetic typhoid conjugate vaccine. Pectin was chemically O-acetylated (OAcPec) to antigenically resemble Vi and conjugated to carrier protein rEPA, a recombinant exoprotein A from Pseudomonas aeruginosa. 25 healthy volunteers, 18–45 years old, were injected once with OAcPec-rEPA. Safety and IgG antibodies reactive with Vi and pectin were analyzed.

Results

No vaccine associated serious adverse reaction was reported. Six weeks after the injection of OAcPec-rEPA, 64% of the volunteers elicited >4-fold rise of anti-Vi IgG. At 26 weeks the level declined, but the difference between the levels at 6 and 26 weeks are not statistically significant. There is a direct correlation between the level of anti-Vi IgG before and after the injection (R² = 0.96). The anti-Vi IgG can be absorbed by Vi, but not by pectin. There was no corresponding increase of anti-pectin after the injection, indicating the antibody response to OAcPec-rEPA was specific to Vi. There is no Vi-rEPA data in US adults for comparison of immune responses. The OAcPec-rEPA elicited significantly less IgG anti-Vi in US adults than those by Vi-rEPA in Vietnamese adults.

Conclusion

The O-acetylated pectin conjugate, a plant based typhoid vaccine, is safe and immunogenic in adult volunteers.ClinicalTrial.gov identifier: NCT00277147, NIH Protocol ID number: OH06-CH-0070, FDA BB Investigation New Drug (IND) number 6989.     

利用马铃薯淀粉制备止血材料方法

目的：利用马铃薯淀粉为原料制备一种具有无毒性、无刺激性、价格低廉、吸水速率快、止血时间短的多微孔多聚糖止血材料。方法：将马铃薯生淀粉经过糊化、酶解、乳化交联、溶剂萃取、洗涤、喷雾干燥筛分、灭菌包装．制成多微孔多聚糖止血微球。结果：制成了止血微球、止血气雾剂、止血粉末3种多微孔多聚糖止血材料：颗粒粒径在50～80txm,均分子量在100000-1900000;吸水倍率在20～100倍;电子显微镜下显示呈圆形或卵圆形微球颗粒．大小均匀。结论：多微孔多聚糖止血材料具有无毒性、无刺激性、价格低廉、吸水速率快、止血时间短的优点,且原料来源丰富、吐产工芦简单可行右广阔酌应用箭导     

卡介苗多糖核酸联合依匹斯汀治疗慢性湿疹58例疗效观察

目的探讨卡介苗多糖核酸联合依匹斯汀治疗慢性湿疹的临床疗效及不良反应情况。方法 116例慢性湿疹病例被随机分为观察组和对照组各58例,观察组肌注卡介苗多糖核酸隔日一次,连续4 w,每日口服依匹斯汀10 mg,联合外用丁酸氢化可的松软膏;对照组每日口服依匹斯汀10 mg联合外用丁酸氢化可的松软膏,涂于患处,每日早晚两次。观察两组患者的治疗效果及不良反应情况。结果观察组治愈26例、显效26例,有效6例,总有效率100%;对照组治愈13例、显效20例、有效20例,总有效率91.4%,差异具有统计学意义(P<0.05)。观察组复发3例(5.17%),对照组复发13例(22.4%),差异具有统计学意义(P<0.05)。两组患者均未观察到严重的不良反应。结论卡介苗多糖核酸联合依匹斯汀治疗慢性湿疹疗效确切,不良反应较轻,能显著降低患者的复发率。     

Acidic polysaccharide of Panax ginseng regulates the mitochondria/caspase-dependent apoptotic pathway in radiation-induced damage to the jejunum in mice

Owing to its susceptibility to radiation, the small intestine of mice is valuable for studying radioprotective effects. When exposed to radiation, intestinal crypt cells immediately go through apoptosis, which impairs swift differentiation necessary for the regeneration of intestinal villi. Our previous studies have elucidated that acidic polysaccharide of Panax ginseng (APG) protects the mouse small intestine from radiation-induced damage by lengthening villi with proliferation and repopulation of crypt cells. In the present study, we identified the molecular mechanism involved. C57BL/6 mice were irradiated with gamma-rays with or without APG and the expression levels of apoptosis-related molecules in the jejunum were investigated using immunohistochemistry. APG pretreatment strongly decreased the radiation-induced apoptosis in the jejunum. It increased the expression levels of anti-apoptotic proteins (Bcl-2 and Bcl-X_S/L) and dramatically reduced the expression levels of pro-apoptotic proteins (p53, BAX, cytochrome c and caspase-3). Therefore, APG attenuated the apoptosis through the intrinsic pathway, which is controlled by p53 and Bcl-2 family members. Results presented in this study suggest that APG protects the mouse small intestine from irradiation-induced apoptosis through inhibition of the p53-dependent pathway and the mitochondria/caspase pathway. Thus, APG may be a potential agent for preventing radiation induced injuries in intestinal cells during radio-therapy such as in cancer treatment.     

马尾松花粉硫酸酯化多糖对大鼠主动脉平滑肌细胞 [Ca2+]i调控及增殖的影响

目的 研究马尾松花粉多糖PPM60-A及其硫酸酯化物SPPM60-A对大鼠动脉平滑肌细胞 [Ca²⁺]_i调控及增殖的影响。方法 常规水提醇沉法制备马尾松花粉多糖,Sephacryl S-400HR色谱分离得PPM60-A,氯磺酸-吡啶法得硫酸酯化物SPPM60-A,酯化度为1.28。酶解法分离制备大鼠动脉平滑肌细胞,测定酯化前后多糖对其胞内 [Ca²⁺]_i和细胞增殖的影响。结果 PPM60-A和SPPM60-A均可以降低 [Ca²⁺]_i,抑制高K⁺和去甲肾上腺素（NE）诱导的钙离子升高,降低高K⁺引起的钙离子水平上升,对NE诱导的血管主动脉平滑肌细胞增殖具有显著的抑制作用。PPM60-A作用效果好于SPPM60-A。结论 PPM60-A及SPPM60-A均能抑制细胞外Ca²⁺内流,抑制血管平滑肌细胞增殖。     

红花多糖对荷瘤小鼠肿瘤组织基质金属蛋白酶-9、组织金属蛋白酶抑制剂-1mRNA表达影响的研究

目的 探讨红花多糖(safflower polysaccharide,SPS)对荷瘤小鼠肿瘤组织中基质金属蛋白酶(matrix metalloproteinases,MMP)-9、组织金属蛋白酶抑制剂1(tissue inhibitors of metalloproteinase,TIMP-1)mRNA表达的影响.方法 BABL/c小鼠腋下接种S180肉瘤,腹腔注射SPS连续10 d,给药结束24 h后取肿瘤组织Real time-PCR法测MMP-9、TIMP-1 mRNA表达水平.结果 SPS低剂量组、中剂量组和高剂量组肿瘤组织中MMP-9的表达量分别是模型对照组的0.452、0.204、0.026倍,TIMP-1的表达量分别是模型对照组的3.4、5.2、10.0倍.结论 SPS能够抑制肿瘤组织中MMP-9基因的表达,促进TIMP-1基因的表达,具有抑制肿瘤及其转移的作用.     

大蒜多糖预处理对缺氧缺糖/复氧复糖大鼠心肌细胞的拮抗作用

目的:研究大蒜多糖(GP)预处理对缺氧缺糖/复氧复糖损伤大鼠心肌细胞的拮抗作用研究,并初步探讨其作用机制。方法:采用连二亚硫酸钠(Na2S2O4)建立乳鼠心肌细胞糖氧剥离的A/R损伤模型,不同剂量GP(10、30和100mg/L)预处理24h后,比色法测定细胞培养液中iNOS和NO含量,测定细胞内SOD活性及MDA含量。结果:与A/R模型组比较,GP预处理可增加胞内SOD活性和培养液中iNOS活力,降低NO释放量和胞内MDA含量。结论:GP预处理对A/R损伤心肌细胞具有明显的抗氧化作用,可能与清除自由基的产生有关。     

黄芪及黄芪多糖对隐孢子虫感染小鼠的免疫调节作用

目的探讨黄芪及黄芪多糖对隐孢子虫感染的免疫抑制小鼠的免疫调节作用。结论 20日龄Balb/c小鼠连续8d灌服醋酸地赛米松后,于第9天经口接种1×106个隐孢子虫卵囊1次,建立隐孢子虫感染模型,再经黄芪水煎剂及黄芪多糖灌胃治疗10d,并设正常对照、模型对照和西药对照组。每日计数粪便隐孢子虫卵囊数量,组织切片HE染色后光学显微镜观察肠组织病理学改变,ELISA法检测血清IL-2、IL-4、IFN-γ水平,流式细胞仪检测T细胞亚群。结果与模型组比较,黄芪水煎剂组、黄芪多糖组和西药组小鼠卵囊排出数量减少,肠组织病理学改变较轻,免疫学检测发现CD4、CD4/CD8及IL-2、IL-4和IFN-γ水平明显升高(P<0.05)。结论黄芪水煎剂及黄芪多糖通过增强免疫功能促进隐孢子虫感染小鼠恢复。     

龙葵多糖细胞毒活性物质基础研究

目的 研究龙葵多糖细胞毒活性的物质基础。方法 从龙葵青果中分离出龙葵粗多糖;Sevage法除去游离蛋白;10%H₂O₂脱色,95%乙醇沉淀,分离出龙葵多糖。龙葵多糖经DEAE-52纤维素柱色谱分离得多糖-蛋白复合物;采用SDS-PAGE电泳法检测多糖-蛋白复合物是否为糖蛋白,并测定其相对分子质量;MTT法检测多糖-蛋白复合物对乳腺癌细胞MCF-7的IC₅₀;多糖-蛋白复合物再经SephadexG-200凝胶柱色谱精制,采用MTT法进行活性检测。结果 SDS-PAGE电泳法测得龙葵多糖-蛋白复合物是相对分子质量3.0×10⁴和2.5×10⁴的2种糖蛋白的复合物,经MTT法测得其对乳腺癌细胞MCF-7的IC₅₀为804.51 μg/mL;多糖-蛋白复合物经SephadexG-200凝胶柱色谱精制得糖蛋白A、B,并测得其对MCF-7的IC₅₀分别为532.96、613.91 μg/mL。结论 龙葵多糖细胞毒活性的物质基础是相对分子质量为3.0×10⁴和2.5×10⁴的2种糖蛋白。     

红豆杉多糖对Beagle犬心肌缺血再灌注损伤模型心肌NADPH氧化酶mRNA及SOD、MDA的影响

目的 观察红豆杉多糖对心肌缺血-再灌注损伤（MIRI）模型心肌损伤及心肌还原型辅酶II（NADPH）氧化酶mRNA、超氧化物歧化酶（SOD）、丙二醛（MDA）的影响。方法 将30只Beagle犬随机分为假手术组、模型组、红豆杉多糖低剂量组与高剂量组、卡维地洛对照组,每组6只,给药7 d后,建立MIRI模型。HE染色,光镜观察心肌组织病理改变;原位杂交检测NADPH氧化酶 p47^phox（NCF-47K）mRNA表达;比色法检测心肌SOD活性和MDA水平。结果 光镜下可见,模型组心肌严重紊乱、断裂,核固缩及胞浆嗜酸性变明显,轻至中度充血、水肿,炎细胞浸润;红豆杉多糖高剂量组心肌细胞紊乱、断裂程度较轻,核固缩及胞浆嗜酸性变明显减少,部分组织仍有轻度充血、水肿。模型组、红豆杉多糖低剂量组心肌NCF-47K mRNA表达较假手术组显著升高（P＜0.01）,红豆杉多糖高剂量组NCF-47K mRNA表达显著低于模型组（P＜0.05）。除红豆杉多糖高剂量组心肌SOD活性显著高于模型组（P＜0.01）外,模型组及各治疗组心肌组织SOD活性较假手术组显著降低（P＜0.01）。模型组及红豆杉多糖低剂量组心肌组织MDA水平较假手术组显著增加（P＜0.05）,红豆杉多糖高剂量组心肌MDA水平显著低于模型组（P＜0.05）。结论 红豆杉多糖可能通过降低心肌组织NADPH氧化酶NCF-47K mRNA表达,升高SOD活性,减少O₂^÷等氧自由基对心肌细胞的损伤,减轻缺血再灌注导致的心肌损伤。