日本血吸虫丝氨酸蛋白酶抑制剂的克隆与表达

目的获得日本血吸虫丝氨酸蛋白酶抑制剂的原核表达蛋白。方法根据GenBank中日本血吸虫丝氨酸蛋白酶抑制剂的序列设计引物,以cDNA为模板聚合酶链反应(PCR)扩增该基因,将其亚克隆入原核表达载体pET28a中,异丙基硫代半乳糖苷(IPTG)诱导表达重组蛋白。结果成功克隆了具有完整开放阅读框的日本血吸虫丝氨酸蛋白酶抑制剂重组质粒,获得相对分子质量约44×103的目的蛋白。结论成功地克隆表达了丝氨酸蛋白酶抑制剂,为进一步研究该蛋白的特性、功能及免疫保护作用奠定了基础。     

Intestinal schistosomiasis among preschool children along the shores of Lake Victoria in Uganda

Schistosomiasis, a disease caused by Schistosoma trematode parasites, affects hundreds of millions of people and accounts for more than 40% of the global health burden due to neglected tropical diseases. In Uganda, intestinal schistosomiasis is endemic in 73 out of 112 districts and about 55% of the population of 36 million individuals are at risk. There is scanty information on the status and burden of schistosomiasis in preschool children less than six years of age in Uganda. This study aimed to assess the status of Schistosoma mansoni infections in children aged 1–5 years in Uganda. S. mansoni prevalence and intensity of infection were examined in 3058 children from 5 districts along Lake Victoria shoreline, eastern Uganda. For each child one stool sample was collected on three consecutive days. The Kato–Katz technique was used to prepare stool smears on slides for microscopic examination. Short interviews with a standardized pre-tested questionnaire prepared in the local language (Lusoga) were administered to each caregiver to identify risk factors associated with S. mansoni infection. An overall S. mansoni prevalence of 39.3% (95% CI: 38.0–41.1%) was estimated out of the 3058 stool samples examined. The geometric mean intensity of S. mansoni among the infected children was 273 (95% CI: 241–305) eggs per gram of faeces. Both prevalence and intensity of infection increased linearly with age (P < 0.0001) and were highest in the age group 49–60 months. Majority (61%) of the children, especially in the age group 12–24 months (84.2%; 95% CI: 75.6–90.1%), were lightly infected. Short interviews with caregivers revealed that preschool children, 1–5 years old, get exposed to S. mansoni infested waters through bathing, playing or swimming. It is important that the Uganda national control programme for schistosomiasis takes preschool children into consideration and that health education on transmission of schistosomiasis is delivered to the endemic communities regularly.     

日本血吸虫(中国大陆株)22.6kDa重组抗原对小鼠免疫保护性的初步研究

目的：为研究日本血吸虫（中国大陆株）22．6kDa抗原的免疫保护性。方法：将其编码cDNA经PCR扩增后亚克隆入载体质粒PGEX—1λt进行表达，并用重组抗原免疫了一批昆明鼠。结果：与对照组相比，重组抗原免疫小鼠获得了38．93％的减虫率。结论：证明重组的日本血吸虫22．6kDa抗原可诱导宿主抗血吸虫感染的部分保护力。     

桑黄多糖缓解日本血吸虫感染小鼠氧化应激及 肝纤维化的实验研究

目的　探讨桑黄醇提多糖（PPI）对日本血吸虫感染小鼠氧化应激、肝肉芽肿和肝纤维化的改善作用。方法　采用日本血吸虫尾蚴玻片贴腹感染法建立日本血吸虫肝病小鼠模型。设健康对照组（A组）、感染对照组（B组）、PPI单独治疗组（C组）、吡喹酮单独治疗组（D组）和PPI加吡喹酮混合治疗组（E组），每组各10只小鼠；除A组外，其他各组每只小鼠感染（30 ± 2）条尾蚴。自感染后42 d开始，D、E组小鼠灌胃给予500 mg/kg吡喹酮，连续2 d；C、E组给予400 mg/kg PPI灌胃，连续给药30 d。HE染色观察小鼠肝组织病理学改变，测定小鼠血清丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）、透明质酸（HA）、层黏连蛋白（LN）及小鼠肝组织匀浆中丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH?PX）、谷胱甘肽还原酶（GSH?R）、谷胱甘肽（GSH）含量，采用免疫组化技术检测小鼠肝组织中转化生长因子?β（TGF?β）、α?平滑肌肌动蛋白（α?SMA）表达水平，采用实时荧光定量PCR检测Nrf2、Gsta4基因表达水平。结果　日本血吸虫感染但未予治疗小鼠出现典型血吸虫病肝病病理改变，PPI干预后能有效减轻小鼠肝虫卵肉芽肿及胶原沉积。血吸虫病肝病小鼠肝脏脂质过氧化加剧，诱导了氧化应激，小鼠血清中MDA含量增加，GSH和各种抗氧化酶含量下降。与B组相比，PPI治疗抑制了脂质过氧化，提高了GSH含量，恢复了抗氧化酶活性。此外，PPI治疗可抑制TGF?β信号通路，提升Nrf2、Gsta4基因表达水平。结论　PPI在治疗血吸虫病肝纤维化方面发挥重要作用，其内在机制可能是通过上调Nrf2和Gsta4基因表达、改善氧化应激损伤，从而抑制肝脏虫卵肉芽肿形成和肝纤维化。     

Serodiagnosis of Schistosoma mansoni infections in an endemic area of Burkina Faso: performance of several immunological tests with different parasite antigens

The performance of indirect haemagglutination assays (IHA), enzyme-linked immunosorbent assays (ELISA) and indirect immunofluorescent antibody tests (IFAT) were compared with 450 sera from a Schistosoma mansoni-endemic area in Burkina Faso. All participants in this survey provided at least one sample each of stool, urine and serum. From those with an egg-negative Kato-Katz thick smear, a second stool sample was examined. IHA was based on either extracts of adult S. mansoni worms (SmIHA) or S. japonicum egg antigen (SjIHA). For ELISA, three antigen preparations were used, namely: (i) soluble S. mansoni adult worm antigens (SWAP); (ii) soluble S. mansoni egg antigens (SEA); and (iii) a cationic exchange fraction of S. mansoni eggs (CEF6). IFAT was performed with S. mansoni male worm sections. Among the egg-excretors, the sensitivity of ELISA was high and egg antigens performed slightly better (SEA, 96%; CEF6, 97%) than worm antigen (94%). Sensitivity of IHA was satisfactory with homologous (Sm, >85%), but not heterologous (Sj, 56%) parasite antigen. In IFAT, the parenchyma-associated fluorescence showed high sensitivity (95%), but gut-associated fluorescence, which is known to be a sensitive diagnostic marker for schistosome-infected European travelers, was observed only in 76% of a sub-sample of 100 of the endemic sera. Among sera from egg-negative individuals, many gave positive reactions in several or all of the tests employed. These reactions (formally "false positive") are considered to represent true infections, since chemotherapy had not yet been delivered to this population. For the purpose of further surveys in Burkina Faso or other resource-poor settings, we suggest IHA as an accurate diagnostic test and propose to further improve its performance by including egg rather than worm antigens.     

日本血吸虫重组信号蛋白14-3-3的纯化及抗体制备

目的制备日本血吸虫(中国大陆株)信号蛋白Sj14-3-3的多克隆抗体与单克隆抗体。方法将合Sj14-3-3重组蛋白的凝胶条带冻干磨粉,免疫家兔,制备抗Sj14-3-3多克隆抗血请;用电洗脱纯化的Sj14-3-3免疫BALB/c小鼠,用杂交瘤技术制备抗Sj14-3-3单克隆抗体。测定所得抗体效价及特异性鉴定。结果获得大量纯化的表达产物;制备的多克隆抗血清双扩效价达1:8～1:64。获得1株能稳定分泌抗Sj14-3-3单抗的杂交瘤细胞株4D9,单抗亚类为IgG1。此株单抗能与重组Sj14-3-3蛋白发生特异性反应。结论获得了高度敏感、特异的抗Sj14-3-3多克隆抗血清及稳定分泌抗Sj14-3-3单抗的杂交瘤细胞。     

日本血吸虫乳酸脱氢酶(SjLDH)结构与功能的生物信息学分析

目的 应用生物信息学分析软件预测日本血吸虫乳酸脱氢酶（SjLDH）氨基酸序列的结构与功能。 方法 应用NCBI、Expasy等在线生物信息学网站及Vector NTI、PCgene等软件包分析SjLDH与其他物种的同源序列，进行多序列同源比对，分析相同的保守位点及催化活性位点，构建分子进化树；预测二级结构、拓扑结构；同源模建预测三级结构；预测主要抗原表位等。 结果 SjLDH与其他物种的同源序列含相同的保守位点及催化活性位点，与华支睾吸虫LDH（CsLDH）同源性最高为75％，与阴道毛滴虫LDH（TvLDH）同源性最低为17%，与人LDH（HsLDH-A，-B，-C）的同源性为58%~60％； SjLDH与果蝇（DmLDH）的进化距离较秀丽隐杆线虫（CeLDH）为近，3种人LDH中与HsLDH-B、-C的进化距离较HsLDH-A为近；该蛋白具有3个跨膜区域，3个高亲水性区域，主要的线性表位98aa~106aa位于膜外，与原虫LDH相同区域差异显著，而与其他LDH有1~3个氨基酸的差异，关键催化位点之一及底物丙酮酸结合区域位于该区域，蛋白质同源模建分析表明该区域位于蛋白表面形成环状结构，3个关键催化位点位于该区域或在其附近。 结论 生物信息学预测结果提示LDH是研究物种分子进化理想的分子；SjLDH可能是免疫诊断、药物作用及疫苗潜在的靶分子。     

3种青蒿素衍生物对日本血吸虫吡喹酮抗性株童虫的体内作用效果观察

目的观察3种青蒿素衍生物双氢青蒿素、青蒿琥酯和蒿甲醚对日本血吸虫吡喹酮抗性株童虫的体内作用效果。方法以经11轮亚治疗剂量吡喹酮筛选的日本血吸虫为吡喹酮抗性株,以未暴露于吡喹酮的日本血吸虫作为吡喹酮敏感株,收集2虫株尾蚴感染小鼠,以300mg/kg双氢青蒿素、青蒿琥酯和蒿甲醚对感染后7~8 d童虫分别进行2次灌服用药(总剂量600 mg/kg),所有小鼠于感染后45 d解剖,收集小鼠体内成虫并计数,计算减虫率和减雌率。结果 300 mg/kg双氢青蒿素、蒿甲醚和青蒿琥酯2日疗法(总剂量600 mg/kg)对日本血吸虫吡喹酮敏感株7~8 d童虫的减虫率为69.8%~71.0%,减雌率为75.4%~79.8%;对日本血吸虫吡喹酮抗性株7~8 d童虫的减虫率为64.6%~66.1%,减雌率为69.3%~71.1%,差异均无统计学意义(均p0.05)。结论 日本血吸虫吡喹酮抗性株对青蒿素类衍生物双氢青蒿素、青蒿琥酯和蒿甲醚依然敏感,青蒿素衍生物与吡喹酮在日本血吸虫中不存在交叉抗药性。     

Comparison of the in vitro Effects of One-day Exposure to Amodiaquine and Praziquantel on Schistosoma mansoni Adult Worm Pairs

It has been demonstrated that continuous exposure to amodiaquine (AQ) alone elicits in vitro antischistosomal activities at concentrations of 1–10 μg/ml. However, orally administered drugs reach a peak blood concentration within one or two hours and then gradually decrease. The blood concentration does not remain at a constant level over several days as in vitro concentration of continuous drug exposure. In vitro activities by one day exposure to AQ better reflect the actual antischistosomal activities after oral administration than those elicited by continuous exposure.The objective of the present study is to compare the antischistosomal potential of one-day exposure to AQ with that to praziquantel (PZQ), a current antischistosomal drug. Schistosoma mansoni adult worm pairs were incubated with 0 (control), 1, 2, 5 and 10 μg/ml AQ as well as 0.01, 0.02, 0.05 and 0.1 μg/ml PZQ for the first day, and were subsequently incubated in drug-free media for a period of 14 days. The one-day exposure to AQ significantly reduced the daily egg output of the worm pairs at 1–10 μg/ml. The inhibitory effect on egg production continued at 5 and 10 μg/ml but proved temporary at 1 and 2 μg/ml. Furthermore, AQ-induced specific morphological alterations (severe swelling and/or localization of hemozoin) were observed in the worms at 5 and 10 μg/ml. The AQ-specific appearance of the male worms gradually faded during subsequent incubation in drug-free media, although the female worms showed elongation. Meanwhile, PZQ inhibited the egg output of adult worm pairs at concentrations of 0.01–0.1 μg/ml during exposure. The inhibitory effect on egg production continued at 0.05 and 0.1 μg/ml but proved temporary at 0.01 and 0.02 μg/ml. Furthermore, PZQ induced a visible contraction and shortening of the male and female worms at 0.05 and 0.1 μg/ml during exposure, but the PZQ-specific alterations quickly disappeared during subsequent incubation in drug-free media. To our knowledge, this is the first report showing that one-day exposure to AQ inhibits the egg production of adult worm pairs at 1–10 μg/ml and induces specific morphological alterations in the worms at 5 and 10 μg/ml. The present findings have important implications for the evaluation of the therapeutic effects of both AQ monotherapy and combination therapy with artesunate on schistosomiasis in clinical field trials.     

日本血吸虫感染小鼠外周血CD4+T细胞亚群动态变化的研究

目的 了解日本血吸虫感染小鼠外周血CD4⁺T细胞亚群水平的动态变化情况,探讨感染进程中CD4⁺T细胞亚群的免疫调控作用。方法 通过日本血吸虫尾蚴腹贴法建立日本血吸虫感染小鼠模型,将18只6周龄C57BL/6J雄性小鼠随机分成正常对照组和日本血吸虫感染组,每组9只。 通过流式细胞染色计数的方法检测感染3周、5周及8周后小鼠外周血CD4⁺T细胞亚群中Th1、Th2、Th17、Treg细胞变化情况。结果 随着日本血吸虫感染进程,与正常对照小鼠相比,感染小鼠外周血CD4⁺T细胞亚群中Th1、Th2、Th17、Treg细胞比例均显著增加。不同细胞亚群比例增加的趋势不尽相同,其中Th1细胞在感染第3周占比较高但其增长较为缓慢,而感染前3周Th2、Treg细胞占比较低但其增加幅度较大,在第8周达到峰值;Th17细胞比例在感染前3周基本无变化,随后显著增加。结论 日本血吸虫感染引起宿主CD4⁺T细胞亚群比例发生变化,本研究发现感染显著增加小鼠外周血Th1、Th2、Th17、Treg细胞比例,感染后3周内小鼠外周血CD4⁺T细胞亚群以Th1细胞为主,5周后Th2、Th17、Treg细胞逐渐占主导地位。本结果为研究日本血吸虫病免疫病理机制和特征提供基础。