莱姆病实验动物模型研究

用从我国新疆全沟硬蜱分离培养的莱姆病螺旋体(XS3),实验感染了新西兰白兔、大耳白兔、13号鼠、大白鼠、中国地鼠、金黄地鼠和豚鼠等7种动物。在一只新西兰白兔发现慢性游走性红斑,一只金黄地鼠和一只13号鼠产生关节炎。患病动物都有较高滴度的抗体。这些结果证实。(1)我国全沟硬蜱莱姆病螺旋体具有足够致病的能力;(2)经培养传代的螺旋体的毒力是稳定的,可引起实验动物莱姆病;(3)莱姆病的发病机理可能与免疫应答有关。另外,证实血中螺旋体的浓度较低,持续时间较短。     

Intracellular persistence ofBorrelia burgdorferi in human synovial cells

To investigate ifBorrelia burgdorferi can persist in resident joint cells, an infection model using cell cultures of human synovial cells was established and compared to the interaction ofBorrelia burgdorferi and human macrophages.Borrelia burgdorferi were found attached to the cell surface or folded into the cell membrane of synovial cells analysed by transmission electron and confocal laser scanning microscopy. In contrast to macrophages, morphologically intactBorrelia burgdorferi were found in the cytosol of synovial cells without engulfment by cell membrane folds or phagosomes.Borrelia burgdorferi were isolated from parallel cultures. Treatment with ceftriaxone eradicated extracellularBorrelia burgdorferi, but spirochetes were reisolated after lysis of the synovial cells.Borrelia burgdorferi persisted inside synovial cells for at least 8 weeks. These data suggested thatBorrelia burgdorferi might be able to persist within resident joint cells in vivo.     

Effect of tick saliva on immune interactions between Borrelia afzelii and murine dendritic cells

Interaction between mouse dendritic cells (DCs) and Borrelia afzelii spirochetes was monitored on three different levels: phagocytosis of spirochetes by DCs, production of cytokines by Borrelia-stimulated DCs and the ability of Borrelia-exposed DCs to activate specific CD4+ T lymphocytes. The effect of Ixodes ricinus tick saliva on each of these interactions was examined. Tick saliva was shown to decrease the number of phagocytosing DCs. The ability of Borrelia-exposed DCs to induce both proliferation and IL-2 production by specific CD4+ T cells was significantly reduced by tick saliva. And surprisingly, we have shown an inhibitory effect of tick saliva on the production of both Th1 (TNF-α and IL-6) and Th2 (IL-10) cytokines by DCs. Our data reveal a complex inhibitory effect of tick saliva on Borrelia-DCs interaction.     

莱姆病螺旋体的转移感染和致病机制

本文主要就莱姆病螺旋体从蜱到宿主动物的转移感染以及在宿主体内存活并致病的机制进行了的阐述,包括螺旋体在蜱内定居以及感染宿主动物过程中蛋白的变化及作用;螺旋体在宿主体内致病的各种机制(病原体本身的作用、免疫逃避、细胞因子的作用、自身免疫)。     

IFA、ELISA和WB用于莱姆病血清学诊断的比较研究

目的比较研究间接免疫荧光试验（IFA）、酶联免疫吸附试验（ELISA）和蛋白免疫印迹试验（WB）3种检测方法对莱姆病血清学的诊断效果。方法收集临床疑似莱姆病患者血清标本及其流行病学和临床资料,分别采用IFA、ELISA和WB进行血清抗伯氏疏螺旋体抗体（IgM和IgG）检测,结合流行病学和临床资料进行综合分析。结果实验共检测莱姆病疑似患者血清398份,ELISA阳性86例,阳性率21.61%,其中IgM阳性27例,IgG阳性59例;IFA阳性82例,阳性率20.60%,其中IgM阳性26例,IgG阳性56例;WB阳性83例,阳性率20.85%,其中IgM阳性31例,IgG阳性52例;并且实验表明,在对于游走性红斑病例的诊断上,WB法阳性率明显高于ELISA和IFA（χ2=6.34,P〈0.05）。结论在莱姆病的实验室诊断中,IFA、ELISA和WB3种方法结合运用,可提高诊断的灵敏性和特异性;WB在排除ELISA和IFA的假阳性结果中有着重要作用。     

Antigenic sites in SARS-CoV-2 spike RBD show molecular similarity with pathogenic antigenic determinants and harbors peptides for vaccine development

The spike protein of coronavirus is key target for drug development and other pharmacological interventions. In current study, we performed an integrative approach to predict antigenic sites in SARS-CoV-2 spike receptor binding domain and found nine potential antigenic sites. The predicted antigenic sites were then assessed for possible molecular similarity with other known antigens in different organisms. Out of nine sites, seven sites showed molecular similarity with 54 antigenic determinants found in twelve pathogenic bacterial species (Mycobacterium tuberculosis, Mycobacterium leprae, Bacillus anthracis, Borrelia burgdorferi, Clostridium perfringens, Clostridium tetani, Helicobacter Pylori, Listeria monocytogenes, Staphylococcus aureus, Streptococcus pyogenes, Vibrio cholera and Yersinia pestis), two malarial parasites (Plasmodium falciparum and Plasmodium knowlesi) and influenza virus A. Most of the bacterial antigens that displayed molecular similarity with antigenic sites in SARS-CoV-2 RBD (receptor binding domain) were toxins and virulent factors. Antigens from Mycobacterium that showed similarity were mainly involved in modulating host cell immune response and ensuring persistence and survival of pathogen in host cells. Presence of a large number of antigenic determinants, similar to those in highly pathogenic microorganisms, not merely accounts for complex etiology of the disease but also provides an explanation for observed pathophysiological complications, such as deregulated immune response, unleashed or dysregulated cytokine secretion (cytokine storm), multiple organ failure etc., that are more evident in aged and immune-compromised patients. Over-representation of antigenic determinants from Plasmodium and Mycobacterium in all antigenic sites suggests that anti-malarial and anti-TB drugs can prove to be clinical beneficial for COVID-19 treatment. Besides this, anti-leprosy, anti-lyme, anti-plague, anti-anthrax drugs/vaccine etc. are also expected to be beneficial in COVID-19 treatment. Moreover, individuals previously immunized/vaccinated or had previous history of malaria, tuberculosis or other disease caused by fifteen microorganisms are expected to display a considerable degree of resistance against SARS-CoV-2 infection. Out of the seven antigenic sites predicted in SARS-CoV-2, a part of two antigenic sites were also predicted as potent T-cell epitopes (KVGGNYNYL^444-452 and SVLYNSASF^366-374) against MHC class I and three (KRISNCVADYSVLYN^356-370, DLCFTNVYADSFVI^389-402, and YRVVVLSFELLHA^508-520) against MHC class II. All epitopes possessed significantly lower predicted IC50 value which is a prerequisite for a preferred vaccine candidate for COVID-19.     

莱姆病流行病学研究进展

莱姆病是由伯氏疏螺旋体感染引起的自然疫源性人兽共患传染病.临床表现复杂多样,可引起多系统、多器官的损害.莱姆病在全世界范围内广泛流行,对人类的健康造成严重危害,而且近年来呈上升趋势.因此,对莱姆病流行病学的深入研究可以有效预防和控制该病的流行蔓延.本文主要从莱姆病的病原体、传染源和传播途径、流行特征等方面对该病的流行病学进展进行较为系统的介绍.     

Seroepidemiological Investigation of Lyme Disease and Human Granulocytic Anaplasmosis among People Living in Forest Areas of Eight Provinces in China

Objective Lyme disease and Human granulocytic anaplasmosis are tick‐borne diseases caused by Borrelia burgdorferi and Anaplasma phagocytophilum respectively. We have investigated infection and co-infection of the two diseases in the population of forest areas of eight provinces in China by measuring seroprevalence of antibodies against B. burgdorferi and A. phagocytophilum. Methods Forest areas in 8 provinces were chosen for investigation using whole sampling and questionnaire survey methods. 3 669 serum samples from people in the forest areas were tested for the presence of antibodies by indirect immunofluorescent assay (IFA). Results Seroprevalence against B. burgdorferi was 3% to 15% and against A. phagocytophilum was 2% to 18% in the study sites in the 8 provinces in China. We also found co-infection of B. burgdorferi and A. phagocytophilum in 7 of the 8 provinces (the exception being the Miyun area in Beijing). The seroprevalence for both B. burgdorferi and A. phagocytophilum was significantly higher among people exposed to ticks than among people who were not exposed to ticks. Conclusion We conclude that both pathogens are endemic in the forest areas in the eight provinces, but the prevalence of B. burgdorferi and A. phagocytophilum differs between the provinces.     

Touchdown PCR检测野生中缅树鼩伯氏疏螺旋体感染

目的用Touchdown PCR检测野生中缅树鼩的伯氏疏螺旋体感染。方法从昆明及其周边地区捕获30只野生中缅树鼩,乙醚深度麻醉后处死,取内脏-30℃保存备用。用总DNA提取试剂盒提取组织总DNA,用紫外可见光分光光度计测定样品的DNA含量,用热启动Touchdown PCR技术检测野生中缅树鼩的伯氏疏螺旋体flaB基因。对PCR产物做凝胶电泳,凝胶成像仪观察并照相。结果Touchdown PCR有良好的特异性和敏感性。实验重复3次,结果一致,野生树鼩的伯氏疏螺旋体DNA阳性率为63．33％（19／30）。结论野生树鼩存在伯氏疏螺旋体感染,并且感染率较高。     

蛋白质芯片对莱姆病患者血清抗鞭毛蛋白抗体的检测分析

目的 探讨蛋白质芯片在莱姆病诊断中的价值。方法 用伯氏疏螺旋体鞭毛蛋白包被N-羟基琥珀酰亚胺修饰的芯片对82例神经性莱姆病、35例环形红斑莱姆病患者和44例正常人对照血清鞭毛蛋白特异性IgM 和 IgG抗体进行检测，并与酶联免疫吸附（ELISA）和蛋白质印迹方法比较。 结果 神经性莱姆病患者血清IgM和IgG抗体水平均高于正常人对照组（P < 0.001）。蛋白质芯片检测神经性莱姆病患者IgM抗体阳性率为76.8%，ELISA检测为63.4%，两种方法检测的阳性率比较，差异有统计学意义（P < 0.05）。蛋白质芯片、ELISA和蛋白质印迹联合检测使环形红斑莱姆病患者IgM和IgG抗体阳性率有所提高。对蛋白质芯片和ELISA两种方法检测的神经性莱姆病、环形红斑莱姆病患者IgM抗体结果分别进行线性分析，发现两种检测方法具有相关性。结论 鞭毛蛋白包被N-羟基琥珀酰亚胺修饰的蛋白质芯片可用于莱姆病临床诊断。