甲肝病毒的分子生物学

甲型肝炎感染第8世纪就有报道,然而,直至1973年甲型肝炎病毒(HAV)才被鉴定。1979年 HAV 首次在细胞中培养成功;1981年从部分基因组中获得 cDNA 克隆;1983年99%以上的病毒基因组被克隆。近年,在 HAV 基因组结构中,不同株间的变异,病毒的抗原位点及减毒的分子学基础方面已积累了大量     

河北石家庄2005-2007年甲肝病毒流行株基因分型研究

目的 了解石家庄地区甲型肝炎病毒(HAV)流行株基因型特征,为HAV溯源研究打下基础.方法 收集了2005-2007年石家庄地区部分甲肝患者急性期血清标本,用HAV结构-非结构区VP1-2A基因引物,经核酸提取,RT-PeR,序列测定,对HAV进行基因分型分析.结果 石家庄地区2005-2007年HAV流行株VP1-2A区核苷酸序列同源性为95%～100%,都属于Ⅰ A亚型;该区氨基酸序列几乎相同.结论 石家庄地区存在有多株甲肝病毒流行株,同一株甲肝病毒可以存在不同地区,同一地区可以检测到相同或不相同的HAV毒株.为今后进一步开展甲肝病毒分子流行病学研究及有效控制HAV流行提供了理论和技术支撑.     

甲型肝炎病毒四种核酸检测方法的比较

目的:比较甲型肝炎病毒(hepatitis A virus,HAV)四种核酸检测方法。方法:采用A、B、C实时荧光定量RT-PCR(RT-qPCR)及D微滴芯片数字RT-PCR(RT-dPCR)分别对HAV质粒标准品、梯度稀释的HAV疫苗进行灵敏度检测;对相关病毒核酸进行特异性检测;用A、B、C方法对40份人工污染HA...     

草莓中甲型肝炎病毒检测方法的比较

目的对草莓中甲型肝炎病毒(hepatitis A virus, HAV)检测的两种检测方法进行优化比较, 以选出最佳的检测方法, 用于草莓中甲肝病毒的检测。方法向已知阴性冷冻草莓标本表面接种不同浓度的HAV, 优化碱性洗脱-PEG浓缩法中的牛肉浸出粉的浓度以及选择最适核酸提取试剂盒, 优化直接裂解法中的最适裂解缓冲液体积, 对草莓标本进行处理, 采用实时荧光定量RT-PCR检测回收的病毒量, 应用SPSS26.0对数据进行统计分析, 并将优化后的两种方法用于实际标本的检测。结果优化后的碱性洗脱-PEG浓缩法的牛肉浸出粉浓度选择3%, 病毒核酸提取试剂盒选择试剂盒B。优化后的直接裂解法的裂解缓冲液体积选择6 ml。对碱性洗脱-PEG浓缩法、直接裂解法在添加HAV不同浓度水平进行比较, 两种方法的HAV病毒回收率分别为21.50±1.06%、5.82±0.01%, 结果表明差异具有统计学意义。同时对四个地区共60份草莓标本进行检测, 结果均为阴性。结论优化后的碱性洗脱-PEG浓缩法灵敏度更高, 更适用于草莓标本中HAV的检测。     

甲型肝炎灭活疫苗(SH株)接种食蟹猴的免疫原性研究

目的 研究甲型肝炎灭活疫苗(SH株)食蟹猴的免疫原性.方法 甲型肝炎病毒SH株接种人胚肺二倍体细胞(MRC-5),培养、收获的病毒液,经纯化、灭活后铝佐剂吸附制成甲型肝炎灭活疫苗.采用食蟹猴进行疫苗的免疫原性研究.结果 接种疫苗后的食蟹猴,体内产生抗HAV抗体和中和抗体,抗核抗体结果为阴性.结论该疫苗具有良好的免疫原性.     

甲型肝炎病毒IgM AlphaLISA检测方法的初步建立

目的 建立甲型肝炎病毒抗体IgM的AlphaLISA检测.方法 浓缩甲型肝炎病毒抗原并生物素化,通过dot-Blot法摸索出生物素化的甲型肝炎病毒的最适量为6 × 10-8ng.优化供体珠、受体微珠、血清等实验反应条件,建立了甲型肝炎病毒的AlphaLISA的IgM检测方法.并对23份感染甲型肝炎病毒的IgM阳性患者和70份健康人的血清进行检测.结果 AlphaLISA甲型肝炎病毒的IgM方法检测:灵敏度(真阳性率)为78％;特异度(真阴性率)为98.5％;假阳性率为1％;假阴性率为22％;阳性预测值为95％;阴性预测值为93％;准确度为94％.结论 建立了均相、快速检测AlphaLISA甲型肝炎病毒IgM检测方法并得到初步应用.     

新疆和田2006年甲肝病毒流行株基因分型研究

目的 了解2006年新疆和田甲型肝炎病毒(HAV)流行株基因型特征,为HAV溯源研究打下基础.方法 收集了新疆和田部分甲肝病人血清标本,用HAV结构.非结构区基因VP1-2A引物,经核酸提取,RT-PCR,序列测定,对HAV进行基因分型研究.结果 新疆和田VP1-2A区HAV核苷酸序列变异为0%～3.9%,分为不同基因簇,但都属1A亚型;VP1-2A区氨基酸序列只有0～2个差异.与已发表的2005年新疆伊犁部分甲肝病毒流行株基因有相同序列或同源性较高.结论 和田有多株甲肝病毒存在,本研究流行可能有多个传染源,多个传播链,在人群免疫水平较低时,引起甲肝流行.结果 表明HAV分子流行病学方法在HAV流行株遗传变异及溯源研究中,以及控制HAV流行中具有重要作用.     

丁型肝炎病毒抗原的原核表达及抗原性分析

目的 利用含T7启动子和His纯化标签pRSET B质粒构建丁型肝炎病毒抗原（HDAg）重组表达质粒（pRSETB-HDAg）,转化宿主菌,表达并纯化,获得生物活性高抗原性强的基因工程重组抗原.方法 将中国河南株HDAg基因片段插入pRSET B表达质粒,转化BL21宿主菌,经IPTG诱导表达.表达产物经Chelating亲和层析纯化后,采用EIA方法分析HDAg的抗原性.结果 重组HDAg稀释1000倍（10 ng/ml）仍与抗体有较强的反应.经与美国HDAg和华美公司生产的HDV诊断试剂同时检测26份HDV阳性参比血清,三者结果比较,除美国抗原漏检1份,检出率为96.15%（25/26份）外,病毒CDC和华美试剂均无漏检,检出率为100%,三者检测结果具有很高的符合率.结论 成功构建了丁型肝炎病毒抗原重组表达质粒（pRSETB-HDAg）,在原核细胞获得稳定高效表达,EIA 检测证明HDAg抗原性好,可用于组装HDV诊断试剂,用于临床丁型肝炎患者的诊断和我国丁型肝炎病毒感染流行病学的调查.     

用噬菌体展示肽库技术筛选甲肝病毒抗原模拟表位

目的 用噬菌体展示肽库技术筛选甲型肝炎(甲肝)病毒抗原模拟表位,为病毒抗原决定簇定位探索可行方法.方法 用纯化的抗甲肝病毒单克隆抗体,对噬菌体展示12肽库进行3轮“吸附-洗脱-扩增”筛选,随机挑取10个克隆,用酶联免疫吸附法(ELISA)对噬菌体克隆进行抗原性鉴定、竞争抑制鉴定及DNA序列测定分析,推导出展示肽氨基酸序列并与甲肝病毒(HAV)代表株结构蛋白氨基酸序列比较.结果 10个噬菌体克隆ELISA检测全为阳性,9个具有一致序列,与HAVHM175株结构蛋白中和活性表位之一:VP1 157-171区具有类似序列,另一株噬菌体克隆在HAVHM175中未发现类似序列,结果表明这些展示肽可能是HAV抗原模拟表位.结论 用噬菌体展示肽库技术筛选得到了HAV模拟表位,为开展病毒模拟表位研究打下了基础.     

甲型肝炎病毒3Cpro蛋白的研究进展

甲型肝炎病毒（Hepatitis A Virus,简称HAV）是甲型病毒性肝炎的病原学致病因子[1],属小核糖核酸病毒科嗜肝病毒属,无包膜,直径27～32 nm,形态发生上与其他的小核糖核酸病毒无异,为二十面体立体对称结构.     

Recombinant envelope protein (rgp90) ELISA for equine infectious anemia virus provides comparable results to the agar gel immunodiffusion

Equine infectious anemia (EIA) is an important viral infection affecting horses worldwide. The course of infection is accompanied generally by three characteristic stages: acute, chronic and inapparent. There is no effective EIA vaccine or treatment, and the control of the disease is based currently on identification of EIAV inapparent carriers by laboratory tests. Recombinant envelope protein (rgp90) was expressed in Escherichia coli and evaluated via enzyme-linked immunosorbent assay (ELISA). There was an excellent agreement (95.42%) between the ELISA results using rgp90 and agar gel immunodiffusion test results. AGID is considered the "gold-standard" serologic test for equine infectious anemia (EIA). After 1160 serum samples were tested, the relative sensitivity and specificity of the ELISA were 96.1% and 96.4%, respectively. Moreover, analysis diagnostic accuracy of the ELISA was performed. The ELISA proved robust. Furthermore, good reproducibility was observed for the negative controls and, positive controls for all plates tested.     

Hybridoma cell lines secreting monoclonal antibodies to foot-and-mouth disease virus type Asia-1

Various immunizing regimens, cell culture requirements and cell fusion conditions were examined for efficient production of hybridomas secreting anti-foot-and-mouth disease virus (FMDV) antibodies. A highly sensitive streptavidin-biotin-based enzyme-linked immunosorbent assay (ELISA) was used for screening of hybridomas for specific antibody production as well as for determining the serotype specificity of the antibodies. Six hybridoma cell lines generating antibodies to FMDV type Asia-1 (vaccine strain 63/72) were produced by fusion of SP2/0 mouse myeloma cells and spleen cells from mice immunized with the inactivated viral antigen. The monoclonal antibodies (MoAb) from four producer clones reacted in ELISA specifically with the intact virus antigen of type Asia-1 without any cross-reactivity with strains of other virus types 0, A and C. Two other clones positive for anti-Asia-1 virus antibodies in ELISA cross-reacted with type C virus strain. The MoAb from three of the four Asia-1 virus type specific clones neutralized the infectivity of the immunizing viral strain. One neutralizing MoAb reacted with the separated VP1 from the immunizing viral strain in immunoblotting.     

Recombinant Hepatitis A Virus Antigen: Improved Production and Utility in Diagnostic Immunoassays

Hepatitis A virus (HAV) immunoassays use cell culture-derived HAV antigen to detect HAV-specific antibodies. The current method of production of HAV antigen in tissue culture is time-consuming and expensive. We previously expressed the HAV open reading frame in recombinant vaccinia viruses (rV-ORF). The recombinant HAV polyprotein was accurately processed and was assembled into subviral particles. These particles were bound by HAV-neutralizing antibodies and were able to elicit antibodies which were detected by commercial immunoassays. The present investigation compared the production of HAV antigen by standard tissue culture methods to the production of HAV antigen with the recombinant vaccinia virus system. In addition, HAV and rV-ORF antigens were assessed for their utility in diagnostic immunoassays. Serum or plasma samples from HAV antibody-positive and antibody-negative individuals were evaluated by immunoassay that used either HAV or rV-ORF antigen. All samples (86 of 86) in which HAV antibody was detected by a commercial enzyme-linked immunosorbent assay (ELISA) also tested positive by the recombinant antigen-based immunoassay (VacRIA). Similarly, all samples (50 of 50) that were HAV antibody negative also tested negative by the VacRIA. The lower limit of detection of HAV antibody was similar among immunoassays with either HAV or rV-ORF antigen. Thus, in the population studied, the sensitivity and specificity of the VacRIA were equivalent to those of the commercial ELISA. Since production of recombinant antigen is faster and less expensive than production of traditional HAV antigen, the development of diagnostic HAV antibody tests with recombinant HAV antigen appears warranted.     

Reversed passive hemagglutination test fails to detect HBsAg in a number of HBeAg positive sera

In endemic areas of hepatitis B virus (HBV) infection, perinatal transmission from asymptomatic HBsAg carrier mothers to infants plays a major role in the transmission of HBV. HBeAg indicates a high level of viral replication and infectivity. Most of the infants born to HBeAg positive mothers become carriers. Prenatal screening of HBsAg would identify infected mothers and thus allow preventive administration of immunoglobulin and immunization to the newborns. Reversed passive hemagglutination assay (RPHA) is commonly used in Thailand for HBsAg screening. However this method has low sensitivity and gives false negative results. Therefore, infants born to HBsAg false negative mothers would not receive proper immunization. This study reveals the rate of false negative results for HBsAg by RPHA in high infectivity sera. Of 985 sera which were HBsAg positive by ELISA, 70 (7.1%) were negative for HBsAg by RPHA. Of these 70 false negative sera, 7 (10%) were HBeAg positive. Our results indicate that RPHA is a less sensitive method for detection of HBsAg than ELISA. RPHA can give false negative results even in sera with high HBV infectivity. Therefore, RPHA should be replaced by EIA for prenatal HBsAg screening or any other screening for HBV infection whenever possible.     

Immunoreactivity of human and rabbit antisera to hepatitis A virus

Rabbit antibodies produced by immunization with complete hepatitis A virions (HAV) recognized all the viral structural proteins and neutralized HAV infectivity in cell culture. Rabbit antibodies to chromatographically purified individual viral proteins and to synthetic peptides representing epitopes on the structural viral protein VP1 neither recognized whole virus nor neutralized infectivity, indicating that native epitopes on the virus surface are necessary for virus recognition and neutralization. Human anti-HAV-positive sera of the acute and convalescent phase of disease recognized and neutralized viral particles. Analysis of the immunoreactivity of these human sera in immunoblot showed that the IgM antibody preferentially recognizes the structural viral proteins VP0 and VP3 of HAV, whereas IgA and IgG antibodies reacted more strongly with VP1.     

持续感染甲型肝炎病毒细胞株的建立和应用

用甲型肝炎病毒（ＨＡＶ）ＨＭ１７５株感染恒河猴胚肾细胞系（Ｆｒｈｋ－４），经过连续传代培养，建立了一株持续感染ＨＡＶ的细胞株。通过１８６代的传代培养和制备ＨＡＶ抗原的实际应用，表明本株带毒培养细胞具有生长速度快、繁殖率高的特点，能大量表达ＨＡＶ抗原。１：４－１：６扩增培养，３～４天可以长成单层，培养７～１０天可以收获ＨＡＶ抗原，用于组装抗ＨＡＶＩｇＭ诊断试剂盒，该试剂盒与美国雅培公司（Ａｂｂｏｔｔ）试剂盒对照检测１４８份血清，总符合率９８．６５（１４６／１４８），与临床对照检测２１３６份病人血清，符合率为９８．９２％（２１１３／２１３６）。     

Diagnosis of herpes simplex virus infection in a clinical setting by a direct antigen detection enzyme immunoassay kit.

A commercial 4-h direct herpes simplex virus (HSV) antigen detection enzyme immunoassay (EIA) kit (Du Pont Herpchek) was evaluated by using 273 clinical specimens obtained in a hospital-based infectious disease practice. The EIA was compared with a standard culture method in which WI38 cells were inoculated within 20 min of sample collection. Cultures were observed for 2 weeks, and positive findings were confirmed by fluorescein-labeled monoclonal antibody (FA) staining. The values for the overall HSV detection rate were 40.7% by the standard culture method and 41.4% by EIA. In eight cases, the EIA was positive, while the culture method was negative; however, clinical data and confirmatory blocking EIA suggested that a true HSV infection was present. For six FA-confirmed, culture-positive samples, the direct EIA was negative; however, an EIA performed on the supernatants of these cultures was positive, suggesting that the failure of the EIA to detect these samples was not due to lack of strain specificity of the test. After confirmatory tests of standard culture and EIA discrepant results, the overall sensitivity of the test was 95.0% (113 of 119) and the specificity was 100% (154 of 154).     

Propagation of human hepatitis A virus in African green monkey kidney cell culture: primary isolation and serial passage.

Human hepatitis A virus (HAV) was propagated in primary African Green Monkey (Cercopithecus aethiops) kidney (AGMK) cell cultures. Three strains of HAV were used: MS-1, SD-11, and HM-175. Cells were inoculated with marmoset-passaged material or human clinical specimens and were stained by direct immunofluorescence to establish the identity of the virus. Both clinical samples and marmoset-passaged material produced immunofluorescence. HAV antigen was found scattered throughout the cytoplasm of inoculated cultures. The HM-175 strain produced the most intense immunofluorescence. This strain of HAV had been serially passaged in cell culture seven times. Blocking experiments with paired human sera from naturally acquired HAV infections and hyperimmune chimpanzee serum from an experimentally infected animal established that the immunofluorescence was specific. The viral antigen was found to be exclusively intracellular. The interval to maximum HAV antigen expression was decreased by serial passage. The HAV strain described herein, which was recovered directly from the stool specimen of a patient with HAV in primary AGMK cell culture, may prove useful as a source of antigen for serological tests and as a candidate vaccine strain.     

Comparative sensitivity of infectivity assay and mouse antibody production (MAP) test for detection of mouse thymic virus (MTLV)

Mouse thymic virus (murid herpesvirus-3; MTLV) is a naturally occurring T lymphotropic herpesvirus of mice. We compared the sensitivity of infectivity assay, which tests for induction of thymic necrosis in newborn mice, and an enzyme immunoassay (ELISA)-based modified mouse antibody production (MAP) test. Infection in adult mice was verified by infectivity assay of salivary glands. Approximately ten times as much virus was required to infect adult mice as newborns. No adults became infected at the lowest dose (just below 1 ID50 by thymic necrosis in newborn mice); a dose tenfold higher resulted in both infection and seroconversion in three out of five mice. At higher doses tested (up to 8000 ID50), all mice became infected and seroconverted. Infected mice shed virus and remained seropositive for at least six months. False positives were observed in ELISA; these could be eliminated by adding control (uninfected) thymic homogenate (1/10 volume of a 10% homogenate) to the sample diluent. These data suggest that the MAP assay can be a reliable and sensitive indicator of infection in adult mice undergoing primary infection. Although slightly less sensitive than infectivity assay for detecting MTLV, the MAP test is likely to detect most samples containing virus. It is recommended that several mice be used for each sample and that all positive serum samples be retested with control thymic homogenate for increased reliability.