E. coli-expressed recombinant norovirus capsid proteins maintain authentic antigenicity and receptor binding capability

The baculovirus expression system has been widely used to produce the capsid proteins of Norovirus (NV) and the proteins form virus-like particles (VLPs) that are useful in many studies, such as immunology, diagnosis, and host-receptor interaction. We report here the application of the E. coli expression system in the production of recombinant NV capsid proteins. In a direct comparison of a previous well-characterized NV strain (VA387), we have demonstrated that the E. coli-expressed capsid proteins maintain the same antigenicity and receptor binding specificity as that of the baculovirus-expressed capsid, although the E. coli-expressed VA387 proteins did not form VLPs. Using the E. coli-expression system, we characterized the receptor-binding patterns of three additional NV strains (OIF1998, Parris Island and VA115), in which OIF1998 binds to HBGA of nonsecretors but did not bind or binds weakly to the HBGA of secretors, as seen in strain VA207. Parris Island binds to HBGA of types A and B but not type O secretors and nonsecretors. VA115 did not show specific binding to any A, B, O secretor nor nonsecretor, which is also observed when the capsid protein of this strain was expressed in baculovirus. Our data indicate that VLP formation is not required for receptor binding, and that the bacteria expression system offers a simple alternative for large production of NV capsid protein for various research purposes, particularly for strains generating low yields in the insect cells.     

Seroprevalence studies using a recombinant norwalk virus protein enzyme immunoassay

A recombinant Norwalk virus (NV) protein enzyme immunoassay was used to study the age of acquisition of NV IgG in various populations. In London, England, there was little evidence of infection during the first 2 years of life. However, the prevalence of NV IgG rose steadily throughout the period that children attend school, reaching a peak of 70% in the group aged 11–16 years. High levels of maternal antibody were detected in infants aged <3 months. Comparison of the acquisition of antibodies to three strains of human calicivirus in Japanese children in northern Japan indicated that although the majority had experienced infection with strains Japan and UK1 by the age of 12 years, only 22% possessed antibodies to NV. In Australian aborigines NV infection occurs early in life; by the age of 6 years over 90% of children were seropositive. © 1994 Wiley-Liss, Inc.     

诺如病毒遗传组I型TaqMan—MGB探针实时荧光RT-PCR的研究

目的建立诺如病毒遗传组I型TaqMan-MGB探针实时荧光RT-PCR快速、特异、灵敏的检测方法，为疾病预防控制提供可靠的依据。方法根据GenBank诺如病毒遗传组I型代表株保守序列设计特异引物对和TaqMan-MGB探针，建立一步法实时荧光RT-PCR快速检测反应体系，优化反应条件，评价反应体系的灵敏度、特异性、重复性．并与常规RT—PCR比较。结果诺如病毒遗传组I型TaqMan-MGB探针实时荧光RT-PCR检测时限短。仅1h就出结果。与轮状病毒、腺病毒、星状病毒、甲肝病毒、诺如病毒遗传组Ⅱ型无交叉反应，最低检出下限为100拷贝／反应，比常规RT—PCR灵敏100倍，5份浓度不同的诺如病毒遗传组I型标本重复检测5次。平均Ct值变异系数范围为0．39％-1．02％。结论诺如病毒遗传组I型TaqMan-MGB探针实时荧光RT—PCR快速、特异、灵敏、重复性好，可应用于突发公共卫生应急检测和诺如病毒遗传组I型监测，提高快速检测能力。     

某高校不同地域学员诺如病毒抗体阳性水平的调查研究

目的拟初步了解NVs感染在我国是否普遍存在，以丰富NVs感染的流行病学信息。方法利用酶联免疫吸附试验检测不同省份学员血清中的诺如病毒rNV、rMX和r387特异性IgG抗体水平。结果来自于22个省、直辖市、自治区的学员血清中均检出rNV、rMX和r387IgG抗体。不同地域学员rNV、rMX和r387IgG抗体阳性率，仅rMX抗体阳性率在不同地域间有显著性差异。结论我国在广泛的空间存在NVs的感染．NVs抗体阳性率与不同地区的社会经济及生活卫生条件有关，不同的基因型的NVs可能在我国的分布有所不同。     

The virucidal effect against murine norovirus and feline calicivirus as surrogates for human norovirus by ethanol-based sanitizers

This study examined the virucidal effects of five types of alcohol-based sanitizers including malic acid and sodium malate, or monoethanolamin, in 58 vol % ethanol (pH 4.0, pH 7.1, pH 11.8), 65 vol % ethanol (pH 4.2), and 75 vol % ethanol (pH 4.4) against murine norovirus (MNV) and feline calicivirus (FCV). The virus titer of MNV was reduced in an ethanol dose-dependent manner under the same pH (about 4.0) condition. Virucidal effect against MNV was correlated with pH when the concentration of ethanol was constant (58 vol %). All the ethanol-based sanitizers provided sufficient virucidal effects against FCV. In conclusion, the virucidal effect of the ethanol-based sanitizer at low concentration of ethanol against norovirus (NoV) is increased when the pH is adjusted to a neutral state.     

Concurrent oral shedding of feline calicivirus and feline herpesvirus 1 in cats with chronic gingivostomatitis

Oral mucosal salivary samples were collected from 25 cats with chronic gingivostomatitis and 24 cats with periodontal disease. Viral culture and isolation of feline calicivirus and feline herpesvirus 1 were performed. Eighty-eight per cent of cats with chronic gingivostomatitis were shedding both viruses, compared to 21% of cats without chronic oral inflammatory disease. Cats with chronic gingivostomatitis are significantly more likely to concurrently shed both feline calicivirus and feline herpesvirus 1 than are cats with classical periodontal disease.     

Gastroenteritis outbreak in British troops, Iraq

Gastroenteritis affected many British military personnel during the war in Iraq. In the first month, 1,340 cases were seen; 73% of patients required hospital admission and 36% were hospital staff. In a survey of 500 hospital staff, 76% reported gastroenteritis, which was more likely in clinical workers. Investigations showed only caliciviruses.     

Feline calicivirus subunit vaccine - a prototype

A vaccine was prepared from a subunit component, antigenically similar to the whole feline calicivirus (FCV) particles. Despite the limited number of animals available for this study we were able to demonstrate that the vaccine protected cats when challenged with a virulent strain of the virus while the non-vaccinates kept as controls developed clinical and histopathological symptoms of the calicivirus disease.     

宁夏地区2011 年病毒性腹泻病例病原学研究

目的 了解2011 年宁夏地区腹泻病例中轮状病毒（HRV）、杯状病毒（HuCV）、星状病毒（HAstV）及肠道腺病毒（HAdV）感染情况。方法 2011 年收集宁夏不同地区腹泻病例的粪便标本,采用ELISA 法检测A组HRV,阳性标本采用RT-PCR 法进行分型鉴定;采用RT-PCR 或PCR法检测HuCV、HAstV和HAdV。结果 共收集腹泻病例粪便标本690 份,其中HRV占2.17%（15/690）、HuCV 占21.74%（150/690）、HAstV 占3.19%（22/690）、HAdv 占6.52%（45/690）、混合感染占4.20%（29/690）。15 份HRV G血清型与P基因型以G1、G3、P［4］型为优势株。结论 2011 年宁夏地区病毒性腹泻主要以＜2 岁婴幼儿为主,HuCV是主要病原体。