Publications by authors named "Tian-Cheng Li"

101 Publications

A New Belief-Based Bidirectional Transfer Classification Method.

IEEE Trans Cybern 2021 Feb 18;PP. Epub 2021 Feb 18.

In pattern classification, we may have a few labeled data points in the target domain, but a number of labeled samples are available in another related domain (called the source domain). Transfer learning can solve such classification problems via the knowledge transfer from source to target domains. The source and target domains can be represented by heterogeneous features. There may exist uncertainty in domain transformation, and such uncertainty is not good for classification. The effective management of uncertainty is important for improving classification accuracy. So, a new belief-based bidirectional transfer classification (BDTC) method is proposed. In BDTC, the intraclass transformation matrix is estimated at first for mapping the patterns from source to target domains, and this matrix can be learned using the labeled patterns of the same class represented by heterogeneous domains (features). The labeled patterns in the source domain are transferred to the target domain by the corresponding transformation matrix. Then, we learn a classifier using all the labeled patterns in the target domain to classify the objects. In order to take full advantage of the complementary knowledge of different domains, we transfer the query patterns from target to source domains using the K-NN technique and do the classification task in the source domain. Thus, two pieces of classification results can be obtained for each query pattern in the source and target domains, but the classification results may have different reliabilities/weights. A weighted combination rule is developed to combine the two classification results based on the belief functions theory, which is an expert at dealing with uncertain information. We can efficiently reduce the uncertainty of transfer classification via the combination strategy. Experiments on some domain adaptation benchmarks show that our method can effectively improve classification accuracy compared with other related methods.
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http://dx.doi.org/10.1109/TCYB.2021.3052536DOI Listing
February 2021

Association between bone marrow fluorodeoxyglucose uptake and recurrence after curative surgical resection in patients with T1-2N0M0 lung adenocarcinoma: a retrospective cohort study.

Quant Imaging Med Surg 2020 Dec;10(12):2285-2296

Department of PET/CT, Radiology Imaging Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.

Background: Evidence regarding the relationship between fluorodeoxyglucose (FDG) uptake in the bone marrow of patients with lung adenocarcinoma and prognosis is limited. This study aimed to identify whether bone marrow FDG uptake is a risk factor for recurrence in patients after curative surgical resection of T1-2N0M0 lung adenocarcinoma.

Methods: From January 2012 to December 2016, we retrospectively enrolled 195 pT1-2N0M0 lung adenocarcinoma patients who underwent both preoperative FDG positron emission tomography/computed tomography (PET/CT) and surgical resection from the lung adenocarcinoma database maintained by the PET/CT department at our hospital. After surgical resection, patients were followed up mainly through regular outpatient examinations. The maximum standardized uptake value (SUV) of the primary tumor, the mean FDG uptake of bone marrow (BM SUV), bone marrow-liver uptake ratio (BLR), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured from the pretreatment FDG PET/CT images. Multi-adjusted Cox proportional hazards models were built to evaluate the independent prognostic value of BLR in predicting recurrence-free survival (RFS). A restricted cubic spline regression model was conducted to provide more precise estimates and examine the shape of the associations between BLR and the risk of recurrence.

Results: The follow-up results showed that 30 of the 195 patients (15.4%) had tumor recurrence. Compared with non-recurrent patients, the primary tumor size in recurrent patients was larger, and the SUV, TLG, and serum C-reactive protein (CRP) levels were higher. Univariate analysis showed that BLR, tumor size, SUV, TLG, and CRP were significantly correlated with postoperative tumor recurrence. After adjustment for conventional confounding factors, the hazard ratio of BLR was 5.01 (95% CI, 1.32, 18.98) for the highest tertile of BLR compared with the lowest tertile. The multi-adjusted spline regression showed that BLR had a linear relationship with log relative risk (RR) for recurrence when BLR was lower than 0.7. Over this level, the effect stabilized, suggesting a saturation effect for BLR at a level of approximately 0.7 at recurrence.

Conclusions: BLR was an independent risk factor for predicting RFS in T1-2N0M0 lung adenocarcinoma patients after curative surgical resection. BLR can be used as a biomarker for evaluating the risk of lung cancer recurrence.
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http://dx.doi.org/10.21037/qims-19-962DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7596406PMC
December 2020

Prevalence and viral loads of polyomaviruses BKPyV, JCPyV, MCPyV, TSPyV and NJPyV and hepatitis viruses HBV, HCV and HEV in HIV-infected patients in China.

Sci Rep 2020 10 13;10(1):17066. Epub 2020 Oct 13.

Department of Virology and Parasitology, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan.

Human polyomaviruses (PyVs) and hepatitis viruses are often more prevalent or persistent in human immunodeficiency virus (HIV)-infected persons and the associated diseases are more abundant than in immunocompetent individuals. Here, we evaluated seroreactivities and viral loads of human PyVs and hepatitis viruses in HIV/AIDS patients and the general population in China in the combination antiretroviral therapy (cART) era. A total of 810 HIV-1-infected patients and age- and sex-matched HIV-negative individuals were enrolled to assess seroprevalence of PyVs BKPyV, JCPyV, MCPyV, TSPyV, and NJPyV and hepatitis viruses HBV, HCV, and HEV. 583 (72%) patients received cART, and among them, 31.2% had undetectable HIV RNA. While no significant difference was observed in prevalence of anti-PyV antibodies between HIV-positive and -negative groups, serum DNA positivity and DNA copy level of MCPyV were higher in the HIV-positive group. Among HIV-infected patients, BKPyV DNA positivity was significantly higher in patients with CD4 + cell counts < 200 cells/mm compared to those with CD4 + cell counts > 500 cells/mm, suggesting possible reactivation caused by HIV-induced immune suppression. Higher HBV and HCV seropositivities but not HEV seropositivity were also observed in the HIV-positive group. Further correlation analyses demonstrated that HBV and HEV are potential risk factors for increased prevalence of PyV infection.
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http://dx.doi.org/10.1038/s41598-020-74244-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7555828PMC
October 2020

Hepatitis E virus infection in 6-month-old pigs in Taiwan.

Sci Rep 2020 10 9;10(1):16869. Epub 2020 Oct 9.

Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-murayama, Tokyo, 208-0011, Japan.

Hepatitis E virus (HEV) is the causative agent of acute hepatitis E. Genotype 3 (G3) and 4 (G4) HEV have recently been identified in and isolated from swine as the main HEV genotypes worldwide. However, there is limited information on HEV infection status among pigs in Taiwan, especially pigs in the stage before transportation to the slaughterhouse. To determine the frequency of HEV infection among pigs in Taiwan, we detected and quantified HEV RNA contained in 295 fecal specimens collected from 6-month-old pigs bred in 30 pig farms located in 8 counties. We found that 25.1% (74/295) of the fecal specimens were positive for HEV RNA by a quantitative real-time reverse transcription-polymerase chain reaction, and the copy number ranged from 2.3 × 10 to 2.08 × 10 copies/g. Amplification of a 338 bp sequence in ORF2 was achieved in 16 of 74 HEV RNA-positive samples, and their nucleotide sequences were determined. Two HEV sequences appeared to belong to subtype 3a of G3 and the remaining 14 HEV sequences belonged to subtype 4b of G4 (G4b). The entire genome sequence of two G4b HEVs was obtained by next-generation sequence analyses, and the phylogenetic analyses indicated that unique G4b HEVs were circulating in pig farms in Taiwan. In the present study, we found that both G3 and G4 HEVs were circulating in Taiwanese pig farms and G4b was the predominant subtype. In addition, the relatively high detection frequency of HEV RNA in the 6-month-old pigs indicated that Taiwanese pigs just before transportation to the slaughterhouse are at risk of carrying HEVs, and thus thorough cooking or heating of pork meat or organs is needed before consumption in Taiwan and possibly in other countries as well.
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http://dx.doi.org/10.1038/s41598-020-74034-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7547095PMC
October 2020

Hollow magnetic-fluorescent nanoparticles for dual-modality virus detection.

Biosens Bioelectron 2020 Dec 2;170:112680. Epub 2020 Oct 2.

Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka, 422-8529, Japan; Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka, 422-8529, Japan. Electronic address:

Combination of magnetic nanomaterials with multifunctionality is an emerging class of materials that exhibit tremendous potential in advanced applications. Synthesizing such novel nanocomposites without compromising magnetic behavior and introducing added functional properties is proven challenging. In this study, an optically active quantum dot (QD) (core) encapsulated inside iron oxide (hollow shell) is prepared as the first electrochemical/fluorescence dual-modality probe. Presence of magnetic layer on the surface enables excellent magnetic property and the encapsulating of QDs on the hollow shell structure maintains the fluorescence with minimal quenching effect, endowing for potential application with fluorescence modality readout. We successfully demonstrate dual-modality sensing utilizing of QD-encapsulated magnetic hollow sphere nanoparticles (QD@MHS NPs) with magnetic separation ability and highly integrated multimodal sensing for the detection of various viruses including hepatitis E virus (HEV), HEV-like particles (HEV-LPs), norovirus-like particles (NoV-LPs), and norovirus (NoV) from clinical specimens. Most importantly, fecal samples of HEV-infected monkey are successfully diagnosed with sensitivity similar to gold standard real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR). This well-defined QD@MHS NPs-based nanoplatform intelligently integrates dual-modality sensing and magnetic bio-separation, which open a gateway to provide an efficient point-of care testing for virus diagnostics.
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http://dx.doi.org/10.1016/j.bios.2020.112680DOI Listing
December 2020

Immunization of human hepatitis E viruses conferred protection against challenge by a camel hepatitis E virus.

Vaccine 2020 10 23;38(46):7316-7322. Epub 2020 Sep 23.

Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan. Electronic address:

Dromedary camel hepatitis E virus is a novel HEV that belongs to the family Hepeviridae, and is classified as genotype 7 HEV (HEV-7). Since HEV-7 is transmitted from camels to humans and causes acute hepatitis E, this virus is a non-negligible pathogen for zoonosis, and a vaccine against HEV-7 infection is urgently needed. Here, we first intravenously inoculated HEV-7 to rhesus monkeys to explore the susceptibility, and we established an animal model. We then used virus-like particles (VLPs) of HEV-1 (HEV-1 VLPs) and HEV-3 (HEV-3 VLPs), a candidate hepatitis E vaccine, to intramuscularly inoculate rhesus monkeys. The monkeys elicited IgG antibody titers as high as >1:102,400 against heterologous HEV-7 without any adjuvants. The HEV-1 VLPs and HEV-3 VLPs-immunized monkeys were challenged intravenously with HEV-7, and they were protected completely from the infection, demonstrating that these VLPs could be a usable vaccine against HEV-7 infection. We also observed that HEV-7-infected rhesus monkeys did not show any liver damage during these experiments. Further efforts are necessary to establish an animal model for investigation of the pathogenesis of hepatitis E caused by HEV-7 infection.
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http://dx.doi.org/10.1016/j.vaccine.2020.09.036DOI Listing
October 2020

Ultrasensitive Detection of the Hepatitis E Virus by Electrocatalytic Water Oxidation Using Pt-CoO Hollow Cages.

ACS Appl Mater Interfaces 2020 Nov 6;12(45):50212-50221. Epub 2020 Oct 6.

Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka 422-8529, Japan.

A sensitive virus detection method applicable for an early stage increases the probability of survival. Here, we develop a simple and rapid detection strategy for the detection of the hepatitis E virus (HEV) by an electrocatalytic water oxidation reaction (WOR) using a platinum (Pt)-incorporated cobalt (Co)-based zeolite imidazole framework (ZIF-67). The surface cavity of ZIF-67 enables the rich loading of Pt NPs, and subsequent calcination etches the cavity, promoting the electrocatalytic activity of Pt-CoO HCs. The Pt-CoO HCs show excellent behavior for the WOR due to the synergistic interaction of Pt and CoO, evaluated by voltammetry and chronoamperometry. The synthesized Pt-CoO HCs are conjugated with anti-HEV antibody (Ab@Pt-CoO HCs); the electrocatalytic activity of Ab@Pt-CoO HCs is combined with that of antibody-conjugated magnetic nanoparticles (MNPs) for HEV detection by a magneto-and-nanocomposite sandwich immunoassay. The sensor is challenged to detect the HEV in spiked serum samples and HEV G7 genotypes collected from the cell culture supernatant, reaching a low limit of detection down to 61 RNA copies mL. This work establishes a free-indicator one-step approach with the controlled design of Pt-CoO HCs, which presents an effective WOR technique for virus detection in a neutral pH solution, which can be extended to electrocatalytic studies in the future integrated biosensing systems.
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http://dx.doi.org/10.1021/acsami.0c13247DOI Listing
November 2020

Persistent infection with a rabbit hepatitis E virus created by a reverse genetics system.

Transbound Emerg Dis 2020 Jul 10. Epub 2020 Jul 10.

Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.

Rabbit hepatitis E virus (HEV) is a novel zoonotic infectious agent. Although a cell culture system to grow the virus has been established, there is currently no reverse genetics system for generating the virus. In this study, capped genomic rabbit HEV RNAs generated by in vitro transcription were transfected into PLC/PRF/5 cells, and the recovered viruses were subsequently passaged in the cells. The cell culture supernatant was capable of infecting rabbits negative for anti-HEV antibody by intravenous and oral inoculation, indicating that rabbit HEV generated by the reverse genetics system is infectious. Genome-wide analyses indicated that no nucleotide sequence change occurred in the virus genomes that were recovered from the cell culture supernatant after transfection and passaged one time or in the virus genomes recovered from faecal specimens of the infected rabbits. Ribavirin, a broad-spectrum anti-viral inhibitor, efficiently abrogated virus replication ex vivo and transiently suppressed the virus growth in the virus-infected rabbits, suggesting that this reagent is a candidate for therapeutic treatment. In addition, transmission of rabbit HEV to rabbits caused persistent infection, suggesting that the virus-infected rabbit could be an animal model for virus-induced hepatitis. The infectious rabbit HEV produced by a reverse genetics system would be useful to elucidate the mechanisms of HEV replication and the pathogenesis of viral hepatitis.
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http://dx.doi.org/10.1111/tbed.13723DOI Listing
July 2020

Characterization of a Novel Rat Hepatitis E Virus Isolated from an Asian Musk Shrew ().

Viruses 2020 07 1;12(7). Epub 2020 Jul 1.

Department of Virology II, 2, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan.

The Asian musk shrew (shrew) is a new reservoir of a rat hepatitis E virus (HEV) that has been classified into genotype HEV-C1 in the species However, there is no information regarding classification of the new rat HEV based on the entire genome sequences, and it remains unclear whether rat HEV transmits from shrews to humans. We herein inoculated nude rats (Long-Evans rnu/rnu) with a serum sample from a shrew trapped in China, which was positive for rat HEV RNA, to isolate and characterize the rat HEV distributed in shrews. A rat HEV strain, S1129, was recovered from feces of the infected nude rat, indicating that rat HEV was capable of replicating in rats. S1129 adapted and grew well in PLC/PRF/5 cells, and the recovered virus (S1129c1) infected Wistar rats. The entire genomes of S1129 and S1129c1 contain four open reading frames and share 78.3-81.8% of the nucleotide sequence identities with known rat HEV isolates, demonstrating that rat HEVs are genetically diverse. We proposed that genotype HEV-C1 be further classified into subtypes HEV-C1a to HEV-C1d and that the S1129 strain circulating in the shrew belonged to the new subtype HEV-C1d. Further studies should focus on whether the S1129 strain infects humans.
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http://dx.doi.org/10.3390/v12070715DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7411586PMC
July 2020

Isolation and characterization of mammalian orthoreoviruses using a cell line resistant to sapelovirus infection.

Transbound Emerg Dis 2020 Nov 14;67(6):2849-2859. Epub 2020 Jun 14.

Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.

Porcine sapelovirus (PSV) is a causative agent of acute diarrhoea, pneumonia and reproductive disorders in swine. Since PSV infection interrupts the growth of other viruses due to its high replication capability in cell culture, the prevention of PSV replication is a keystone to the isolation of non-PSV agents from PSV-contaminated samples. In the present study, we established the PSV infection-resistant cell line N1380 and isolated three mammalian orthoreoviruses (MRV) strains, sR1521, sR1677 and sR1590, from swine in Taiwan. These Taiwanese isolates induced an extensive cytopathic effect in N1380 cells upon infection. The complete and empty virus particles were purified from the cell culture supernatants. Next-generation sequencing analyses revealed that the complete virus particles contained 10 segments, including 3 large (L1, L2 and L3), 3 medium (M1, M2 and M3) and 4 small (S1, S2, S3 and S4) segments. In contrast, the empty virus particles without genome were non-infectious. Phylogenetic analyses revealed that the Taiwanese strains belong to serotype 2 MRV (MRV2). We established an ELISA for the detection of IgG antibody against MRV2 by using the empty virus particles as the antigen. A total of 540 swine and 95 wild boar serum samples were collected in Japan, and the positive rates were 100% and 52.6%, respectively. These results demonstrated that MRV infection occurred frequently in both swine and wild boar in Japan. We established a cell line that is efficient for the isolation of MRV, and the ELISA based on the naturally occurring empty particles would be of great value for the surveillance of MRV-related diseases.
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http://dx.doi.org/10.1111/tbed.13655DOI Listing
November 2020

Seroprevalence of Dromedary Camel HEV in Domestic and Imported Camels from Saudi Arabia.

Viruses 2020 05 18;12(5). Epub 2020 May 18.

Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia.

Hepatitis E Virus (HEV) imposes a major health concern in areas with very poor sanitation in Africa and Asia. The pathogen is transmitted mainly through ingesting contaminated water or food, coming into contact with affected people, and blood transfusions. Very few reports including old reports are available on the prevalence of HEV in Saudi Arabia in humans and no reports exist on HEV prevalence in camels. Dromedary camel trade and farming are increasing in Saudi Arabia with importation occurring unidirectionally from Africa to Saudi Arabia. DcHEV transmission to humans has been reported in one case from the United Arab Emeritus (UAE). This instigated us to perform this investigation of the seroprevalence of HEV in imported and domestic camels in Saudi Arabia. Serum samples were collected from imported and domestic camels. DcHEV-Abs were detected in collected sera using ELISA. The prevalence of DcHEV in the collected samples was 23.1% with slightly lower prevalence in imported camels than domestic camels (22.4% vs. 25.4%, value = 0.3). Gender was significantly associated with the prevalence of HEV in the collected camels ( value = 0.015) where males (31.6%) were more infected than females (13.4%). This study is the first study to investigate the prevalence of HEV in dromedary camels from Saudi Arabia. The high seroprevalence of DcHEV in dromedaries might indicate their role as a zoonotic reservoir for viral infection to humans. Future HEV seroprevalence studies in humans are needed to investigate the role of DcHEV in the Saudi human population.
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http://dx.doi.org/10.3390/v12050553DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290434PMC
May 2020

Advancement of capture immunoassay for real-time monitoring of hepatitis E virus-infected monkey.

Anal Chim Acta 2020 May 12;1110:64-71. Epub 2020 Feb 12.

Department of Applied Biological Chemistry, College of Agriculture, Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka, 422-8529, Japan; Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka, 422-8529, Japan. Electronic address:

Rapid increasing outbreak of Hepatitis E virus (HEV) shows an urgent need of HEV detection. Instead of time consuming and expensive RT-qPCR, an efficient and quick monitoring system is in utmost demand which can be comparable with the RT-qPCR in term of reliability and detection limit. An advanced platform for immunoassay has been constructed in this study by a nanozyme that constitutes anti-HEV IgG antibody-conjugated gold nanoparticles (Ab-AuNPs) as core and in situ silver deposition on the surface of Ab-AuNPs as outer shell. The virus has been entrapped on the nanocomposites while the silver-shell has decomposed back to the silver ions (Ag) by adding a tetramethylbenzidine (TMBZ) and hydrogen peroxide (HO) which indirectly quantifies the target virus concentration. Counterpart to only applying nanozyme, by incorporation of the enhanced effect of Ag shell on the AuNP-based nanozyme, the advance deposition has been confirmed to prove the signal amplification mechanism in the proposed immunoassay. Most importantly, the sensor performances have examined on the HEV, collected from the HEV-infected monkey over a period of 45 days. It was successfully correlated with the standard RT-qPCR data, showing the applicability of this immunoassay as a real-time monitoring on the HEV infection. The in situ formation of AuNPs@Ag as nanozyme in this capture immunoassay leads to a promising advancement over the conventional methods and nanozyme-based immunoassay in real application which can be a good substitute of RT-qPCR in near future.
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http://dx.doi.org/10.1016/j.aca.2020.02.020DOI Listing
May 2020

Characterization of a Novel Simian Sapelovirus Isolated from a Cynomolgus Monkey using PLC/PRF/5 Cells.

Sci Rep 2019 12 27;9(1):20221. Epub 2019 Dec 27.

Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan.

We isolated a novel simian sapelovirus (SSV), Cam13, from fecal specimen of a cynomolgus monkey by using PLC/PRF/5 cells. The SSV infection of the cells induced an extensive cytopathic effect. Two types of virus particles with identical diameter (~32 nm) but different densities (1.348 g/cm and 1.295 g/cm) were observed in the cell culture supernatants. The RNA genome of Cam13 possesses 8,155 nucleotides and a poly(A) tail, and it has a typical sapelovirus genome organization consisting of a 5' terminal untranslated region, a large open reading frame (ORF), and a 3' terminal untranslated region. The ORF encodes a single polyprotein that is subsequently processed into a leader protein (L), four structural proteins (VP1, VP2, VP3, and VP4) and seven functional proteins (2A, 2B, 2C, 3A, 3B, 3C, and 3D). We confirmed that 293 T, HepG2/C3A, Hep2C, Huh7 and primary cynomolgus monkey kidney cells were susceptible to SSV infection. In contrast, PK-15, Vero, Vero E6, RD-A, A549, and primary green monkey kidney cells were not susceptible to SSV infection. We established an ELISA for the detection of IgG antibodies against SSV by using the virus particles as the antigen. A total of 327 serum samples from cynomolgus monkeys and 61 serum samples from Japanese monkeys were examined, and the positive rates were 88.4% and 18%, respectively. These results demonstrated that SSV infection occurred frequently in the monkeys. Since Cam13 shared 76.54%-79.52% nucleotide sequence identities with other known SSVs, and constellated in a separate lineage in the phylogeny based on the entire genome sequence, we propose that Cam13 is a new genotype of the simian sapelovirus species.
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http://dx.doi.org/10.1038/s41598-019-56725-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6934677PMC
December 2019

Reply to "A comment on 'Current status of hepatitis E virus infection at a rhesus monkey farm in China'".

Authors:
Tian-Cheng Li

Vet Microbiol 2019 10 7;237:108383. Epub 2019 Aug 7.

Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-murayama, Tokyo, 208-0011 Japan. Electronic address:

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http://dx.doi.org/10.1016/j.vetmic.2019.108383DOI Listing
October 2019

Characterization of the self-assembly of New Jersey polyomavirus VP1 into virus-like particles and the virus seroprevalence in Japan.

Sci Rep 2019 09 11;9(1):13085. Epub 2019 Sep 11.

Department of Virology II, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, 208-0011, Japan.

New Jersey polyomavirus (NJPyV) was discovered in 2014 in a pancreatic transplant recipient's vascular endothelial cells. Here, in the recombinant baculovirus system, VP1 protein of NJPyV expressed in insect cells was processed. The protein self-assembled into virus-like particles (NJPyV-LPs) in a cell-type-dependent manner, and the particles were then released into the culture media. Spherical ~50-nm-dia. NJPyV-LPs of uniform size with morphology resembling that of the native particles of polyomaviruses were purified from the fraction at 1.33 g/cm in supernatants of VP1-expressing Sf9 cells. We investigated the antigenic properties of purified NJPyV-LPs and performed a VLP-based enzyme immunoassay to determine the age-specific prevalence of NJPyV infection in a general Japanese population aged 1-70 years. The overall seropositivity rate of anti-NJPyV antibodies was only 1.8%. This might be explained by the low circulation of NJPyV in Japan. This is the first report of a large-scale serological survey of NJPyV in Asia (n = 1,050).
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http://dx.doi.org/10.1038/s41598-019-49541-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6739320PMC
September 2019

Electrical pulse-induced electrochemical biosensor for hepatitis E virus detection.

Nat Commun 2019 08 19;10(1):3737. Epub 2019 Aug 19.

Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan.

Hepatitis E virus (HEV) is one of the leading causes of acute viral hepatitis worldwide. In this work, a pulse-triggered ultrasensitive electrochemical sensor was fabricated using graphene quantum dots and gold-embedded polyaniline nanowires, prepared via an interfacial polymerization and then self-assembly approach. Introducing an external electrical pulse during the virus accumulation step increases the sensitivity towards HEV due to the expanded surface of the virus particle as well as the antibody-conjugated polyaniline chain length, compared to other conventional electrochemical sensors. The sensor was applied to various HEV genotypes, including G1, G3, G7 and ferret HEV obtained from cell culture supernatant and in a series of fecal specimen samples collected from G7 HEV-infected monkey. The sensitivity is similar to that detected by real-time quantitative reverse transcription-polymerase chain (RT-qPCR). These results suggests that the proposed sensor can pave the way for the development of robust, high-performance sensing methodologies for HEV detection.
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http://dx.doi.org/10.1038/s41467-019-11644-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6700141PMC
August 2019

Integrin α3 is involved in non-enveloped hepatitis E virus infection.

Virology 2019 10 30;536:119-124. Epub 2019 Jul 30.

Department of Quality Assurance and Radiological Protection, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan. Electronic address:

Hepatitis E virus (HEV) causes acute and fulminant hepatitis worldwide. Although enveloped (e) and non-enveloped (ne) forms of HEV have been discovered, host factors involved in infection, including receptors, remain to be elucidated. Here, we identified integrin α3 (encoded by ITGA3), a protein that binds and responds to the extracellular matrix, as an essential host factor for HEV infection. Integrin α3 expression was lower in four HEV-non-permissive cell subclones than in an HEV-permissive subclone. ITGA3 knockout cells lost HEV permissibility, suggesting that integrin α3 is critical for HEV infection. Stable expression of integrin α3 in an HEV-non-permissive subclone provided permissibility only to infection by neHEV; expression of integrin α3 lacking the ectodomain did not. Direct interaction between neHEV and the integrin α3 ectodomain was confirmed by co-precipitation using a soluble integrin α3-Fc. These results strongly suggest that integrin α3 is a key molecule for cellular attachment and entry of neHEV.
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http://dx.doi.org/10.1016/j.virol.2019.07.025DOI Listing
October 2019

High Prevalence of Hepatitis E Virus Infection in Imported Cynomolgus Monkeys in Japan.

Jpn J Infect Dis 2019 Nov 31;72(6):429-431. Epub 2019 Jul 31.

Department of Virology II, National Institute of Infectious Diseases.

Cynomolgus monkeys are important experimental animals for hepatitis E virus (HEV) infection. In Japan, cynomolgus monkeys are mainly imported from Asian countries for use at animal facilities and institutions. However, the status of HEV infection in cynomolgus monkeys remains unclear. Overall, 187 pairs of serum and fecal samples were collected from cynomolgus monkeys (Macaca fascicularis) imported from China and Cambodia to detect anti-HEV immunoglobulin (Ig) G and IgM antibodies, as well as HEV RNA. Based on an enzyme-linked immunosorbent assay using HEV-like particles derived from genotype 3 HEV as the antigen, 183 of 187 (97.9%) and 102 of 187 (54.5%) samples tested positive for anti-HEV IgG and IgM antibodies, respectively. In contrast, all 45 serum samples collected from cynomolgus monkeys bred and grown at the Tsukuba Primate Research Center, Japan tested negative for both antibodies. However, real-time quantitative reverse transcription polymerase chain reaction detected no HEV RNA in any of the 187 serum and fecal samples. These results strongly indicated that HEV infection is common in imported cynomolgus monkeys. A source of HEV-free monkeys for HEV studies is urgently needed.
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http://dx.doi.org/10.7883/yoken.JJID.2019.129DOI Listing
November 2019

Current status of hepatitis E virus infection at a rhesus monkey farm in China.

Vet Microbiol 2019 Mar 13;230:244-248. Epub 2019 Feb 13.

Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan. Electronic address:

Rhesus and several other species of monkeys are susceptible to genotypes of hepatitis E virus (HEV), and these species are thus commonly used as animal models for experimental HEV infection. However, information regarding HEV infection in monkeys in nature or at monkey farms is limited. To investigate the status of HEV infection in rhesus monkeys at farms, we collected 548 serum and 48 fecal samples from a rhesus monkey farm in China, and analyzed their levels of anti-HEV IgG antibodies and HEV RNAs. An enzyme-linked immunosorbent assay using genotype 3 HEV-like particles as antigen revealed anti-HEV IgG-positivity in 388 (70.8%) monkeys. The antibody-positive rates in the 1-year-old and 2-year-old monkeys were significantly lower than those in monkeys >3 years old. The antibody-positive rate was greatly increased from 7.4% in the 2-year-old monkeys to 100% in the 3-year-olds, suggesting that the latter received HEV infection at a high frequency. HEV RNA was detected in one of 88 sera from 1- and 2-year-old monkeys and 10 of 48 fecal specimens from 3-year-old monkeys by reverse transcription-polymerase chain reaction. Phylogenetic analyses revealed that the HEV strain RmKM15 was present in a serum sample that belonged to subtype 4b in genotype 4, whereas 10 strains detected in the fecal specimens belonged to subtype 4 h, suggesting that two genetically different strains were circulating at the farm. However, no significant clinical signs were observed in these monkeys. Further studies are required to identify the source of infection and to evaluate the pathogenicity of HEV in rhesus monkeys.
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http://dx.doi.org/10.1016/j.vetmic.2019.01.021DOI Listing
March 2019

Genotype 5 Hepatitis E Virus Produced by a Reverse Genetics System Has the Potential for Zoonotic Infection.

Hepatol Commun 2019 Jan 30;3(1):160-172. Epub 2018 Nov 30.

Department of Virology II National Institute of Infectious Diseases Tokyo Japan.

Neither an animal model nor a cell culture system has been established for the genotype 5 hepatitis E virus (G5 HEV), and the pathogenicity, epidemiology, and replication mechanism of the virus remain unclear. In this study, we used a reverse genetics system to generate G5 HEV and examined the possibility of zoonotic infection. Capped and uncapped genomic G5 HEV RNAs generated by transcription were transfected into PLC/PRF/5 cells. Infectious G5 HEV was recovered from the capped G5 HEV RNA-transfected PLC/PRF/5 cells and the subsequently passaged cells. G5 HEV was also recovered from uncapped G5 HEV-transfected PLC/PRF/5 cells after a longer lag phase, suggesting that the 5'-cap structure is not essential but affected the efficiency of G5 HEV replication. G5 HEV infection was neutralized not only by anti-G5 HEV-like particles (HEV-LPs) antibody, but also by anti-G1, anti-G3, anti-G4, and anti-G7 HEV-LPs antibodies. G5 HEV was capable of infecting cynomolgus monkeys negative for anti-HEV antibody but not animals positive for anti-G7 HEV immunoglobulin G (IgG), indicating that cynomolgus monkeys were susceptible to G5 HEV, and the serotype of G5 HEV was identical to that of G7 HEV and human HEVs. Moreover, G5 HEV replication was efficiently inhibited by ribavirin and partially inhibited by sofosbuvir. Infectious G5 HEV was produced using a reverse genetics system, and the antigenicity was identical to that of human HEVs and G7 HEV. Transmission of G5 HEV to primates was confirmed by an experimental infection, providing evidence of the possibility of zoonotic infection by G5 HEV.
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http://dx.doi.org/10.1002/hep4.1288DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6312656PMC
January 2019

Detection of Subgenotype IA and IIIA Hepatitis A Viruses in Rivers Flowing through Metro Manila, the Philippines.

Jpn J Infect Dis 2019 Jan 31;72(1):53-55. Epub 2018 Aug 31.

Department of Virology II, National Institute of Infectious Diseases.

Hepatitis A virus (HAV) is a common infectious etiology of acute hepatitis worldwide. The Philippines remains highly endemic for hepatitis A, but there is still a lack of information about HAV in the country. To evaluate the HAV contamination in environmental water in the Philippines, we conducted the detection and genetic analyses of HAV RNA in samples from river water. Twelve water samples were collected at 6 sampling sites of 3 rivers in Metro Manila, in both the dry and wet seasons in 2012 and 2013. The HAV RNA was detected in all the 6 samples collected in the dry season, and in one sample from the wet season. Phylogenetic analysis confirmed that the HAV strains detected in the river water included multiple sequences belonging to subgenotypes IA and IIIA. This indicates that at least 2 genotypes of the HAV strains are circulating in the environment in the Philippines, posing a risk of HAV infection to not only residents, but also tourists, especially in the dry season.
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http://dx.doi.org/10.7883/yoken.JJID.2018.148DOI Listing
January 2019

Prediction of Occult Lymph Node Metastasis Using Tumor-to-Blood Standardized Uptake Ratio and Metabolic Parameters in Clinical N0 Lung Adenocarcinoma.

Clin Nucl Med 2018 Oct;43(10):715-720

From the Department of PET/CT, Radiology Imaging Center, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China.

Purpose: We aimed to investigate whether the tumor-to-blood SUV ratio (SUR) and metabolic parameters of F-FDG uptake could predict occult lymph node metastasis (OLM) in clinically node-negative (cN0) lung adenocarcinoma.

Materials And Methods: We retrospectively reviewed 157 patients with cN0 lung adenocarcinoma who underwent both preoperative F-FDG PET/CT and surgical resection with the systematic lymph node dissection. The SUVmax, SUVmean, MTV, and total lesion glycolysis (TLG) of the primary tumor was measured on the PET/CT workstation. SURmax, SURmean, and TLGsur were derived from each of them divided by descending aorta SUVmean. These PET parameters and clinicopathological variables were analyzed for OLM.

Results: In our study, OLM was detected in 31 (19.7%) of 157 patients. Significantly higher values of tumor size, SUVmax, SUVmean, MTV, TLGsuv, SURmax, SURmean, and TLGsur were found in patients with OLM. In receiver operating characteristic curve analysis, the optimal cutoff values of the above parameters were 29.50, 4.38, 2.45, 6.37, 44.13, 5.30, 1.86, and 28.24, respectively. The multivariate analysis showed that TLGsur (odds ratio, 1.024; P = 0.002) was the most potent associated factor for the prediction of OLM in cN0 lung adenocarcinoma.

Conclusions: TLGsur showed the most powerful predictive performance than the other PET parameters for the prediction of OLM in cN0 lung adenocarcinoma. This normalized volumetric parameter would be helpful in selection of sublobar resection or aggressive tailored treatments in patients with cN0 lung adenocarcinoma.
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http://dx.doi.org/10.1097/RLU.0000000000002229DOI Listing
October 2018

Will Happiness Improve the Psychological Integration of Migrant Workers?

Int J Environ Res Public Health 2018 05 3;15(5). Epub 2018 May 3.

Zhongshan Institute, University of Electronic Science and Technology of China, Guangzhou 528400, China.

Happiness is a major factor that influences people’s perceptions and behavior. Two-stage least squares regression was applied to investigate the effect of happiness on the psychological integration of migrant workers in China. The data for a total of 1625 individuals were obtained from the 2014 China Labor-force Dynamics Survey (CLDS). This study describes happiness from three main aspects: happiness, life satisfaction, and economic satisfaction. The psychological integration includes two dimensions of settlement willingness, and trust level; these have gone through dimension-reduced processing by using the weighted average method. The empirical evidence shows, first, that happiness has a significantly positive effect on the psychological integration of migrant workers and second, that the sense of life satisfaction in particular plays a more significant role. The acceleration of the social and political integration in migrant workers will enhance their psychological integration. Additionally, social, cultural and economic integration is found to influence migrant workers’ psychological integration by promoting happiness. Happiness between different generations of migrant workers was found to have a noticeably positive impact on their psychological integration; however, the happiness of the younger migrant workers was more perceivable than that of the other generations. Preferential policies should therefore be provided to improve the happiness of migrant workers.
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http://dx.doi.org/10.3390/ijerph15050900DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5981939PMC
May 2018

Evaluation of Heating Conditions for Inactivation of Hepatitis E Virus Genotypes 3 and 4.

J Food Prot 2018 06;81(6):947-952

2 Department of Virology II, National Institute of Infectious Disease, 4-7-1, Gakuen, Musashimurayama, Tokyo 208-0011, Japan.

Hepatitis E virus (HEV) is a causative agent of acute hepatitis throughout the world. HEV genotypes 1 through 4 infect humans, whereas genotypes 3 and 4 (Gt3 and Gt4) also infect other animals. In developed countries, the main HEV infection route is by foodborne transmission, resulting from the consumption of undercooked meat. It is important to know the criteria for HEV control in daily cooking. In this study, we assessed the heat conditions required to inactivate HEV Gt3 and Gt4 in culture supernatants and spiked minced pork meat. HEV inactivation was determined by measuring viral RNA amplification in PLC/PRF/5 cell culture. In our cell culture assay, an inoculum containing HEV titer that is equivalent to >10 genome RNA copies can be determined as infectious. The internal temperature of pork during heating was measured to represent that achieved during cooking. Both HEV Gt3 and Gt4 were inactivated in culture supernatants heated at >65°C for 5 min and at >80°C for 1 min and in minced meat at 70°C for 5 min. Inoculated culture supernatant contained 10 HEV genome RNA copies (10 infectious units [IU]); therefore, it was indicated that HEV titer decreased >3 log IU after heating. In a comparison of Gt3 and Gt4, Gt4 showed slightly greater heat stability than Gt3. Boiling showed superior heating efficacy compared with roasting, and pork liver was slightly easier to heat than pork loin. Heating for 5 min by both boiling and roasting increased the internal temperature of pork products to more than 70°C. Although our data revealed that HEV Gt4 was slightly more heat stable than Gt3, both genotypes were inactivated by the appropriate heating conditions. Therefore, the risk of HEV foodborne infection could be mitigated by the appropriate cooking of pork meat. It is also important that both the supplier and the consumer are cognizant of the risk of HEV foodborne infection from livestock products.
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http://dx.doi.org/10.4315/0362-028X.JFP-17-290DOI Listing
June 2018

Small Animal Models of Hepatitis E Virus Infection.

Cold Spring Harb Perspect Med 2019 08 1;9(8). Epub 2019 Aug 1.

Department of Virology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan.

Novel hepeviruses have been recovered from many different animal species in recent years, increasing the diversity known to exist among the , which now include two genera, and Multiple viral genotypes in the species are able to replicate and cause acute hepatitis E in humans, and thus represent an important public health problem in industrialized as well as developing countries. Although hepatitis E virus (HEV) infections typically result in acute and self-limited hepatitis, immunocompromised and transplant patients are vulnerable to prolonged infections and to chronic hepatitis. Cell culture systems have been established for several HEV strains and offer new opportunities for the study of HEV biology. Similarly, a variety of new small animal models have been developed, using either nonhuman hepeviruses in their cognate hosts as surrogates for human HEV, or human HEV infection of immunodeficient mice with chimeric livers engrafted with human hepatocytes. These new models provide several advantages over previous nonhuman primate models of hepatitis E infection and will facilitate studies of pathogenicity, cross-species infection, mechanisms of virus replication, and vaccine and antiviral agent development. This article reviews the current understanding of small animal models for HEV.
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http://dx.doi.org/10.1101/cshperspect.a032581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6671932PMC
August 2019

Determination of Ferret Enteric Coronavirus Genome in Laboratory Ferrets.

Emerg Infect Dis 2017 09;23(9):1568-1570

Ferret enteric coronavirus (FRECV) RNA was detected in laboratory ferrets. Analysis of the complete genome sequence of 2 strains, FRCoV4370 and FRCoV063, revealed that FRECV shared 49.9%-68.9% nucleotide sequence identity with known coronaviruses. These results suggest that FRECV might be classified as a new species in the genus Alphacoronavirus.
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http://dx.doi.org/10.3201/eid2309.160215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5572892PMC
September 2017

Serological evidence of hepatitis E virus infection in dromedary camels in Ethiopia.

J Virol Methods 2017 08 21;246:34-37. Epub 2017 Apr 21.

Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan.

The genome of dromedary camel hepatitis E virus (DcHEV) has been detected in stool and serum samples from dromedary camels, but the sero-epidemiological information of DcHEV infection remains unclear. A total of 246 serum samples collected from dromedary camels (Camelus dromedarius) in Ethiopia, and 40 serum samples from Bactrian camels (Camelus ferus) in Mongolia were examined for the detection of anti-DcHEV IgG antibody by a newly developed enzyme-linked immunosorbent assay (ELISA) by using DcHEV-like particles (DcHEV-LPs) as the antigen. The results revealed that 55 of the 246 (22.4%) dromedary camels were positive for anti-DcHEV IgG, whereas all 40 samples from the Bactrian camels were negative for DcHEV IgG antibody. A total of 98 serum samples from dromedary camels, including 25 anti-DcHEV-IgG positive samples, were used for the detection of DcHEV RNA by reverse transcription-polymerase chain reaction (RT-PCR), however, no positive samples were identified. These results suggested that the DcHEV infection occurred in the dromedary camels in Ethiopia. Further studies are required to determine whether Bactrian camels are susceptible to DcHEV infection. In addition, not only DcHEV-LPs, but also virus-like particles (VLPs) delivered from G1, G3 and G5 HEV are likely applicable for the detection of the anti-DcHEV IgG antibody.
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http://dx.doi.org/10.1016/j.jviromet.2017.04.008DOI Listing
August 2017

Genetic and physicochemical analyses of a novel ferret hepatitis E virus, and clinical signs of infection after birth.

Infect Genet Evol 2017 07 25;51:153-159. Epub 2017 Mar 25.

Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan.

A novel cluster of five ferret hepatitis E virus (HEV) strains was detected from nine laboratory ferrets (Mustela putorius furo) imported from a ferret farm in the U.S. Our detection of ferret HEV RNA and anti-HEV antibodies, and alanine aminotransferase (ALT) value assessment indicated that all of the 9 ferrets were infected with ferret HEV, and that the infection exhibited three patterns: sub-clinical infection (n=2), acute hepatitis (n=6) and persistent infection (n=1). Next-generation sequence analyses of the entire genome sequences of the five strains revealed that their nucleotide sequence identities ranged from 99.5% to 99.9%, indicating that genetically similar ferret HEVs had been circulating at this the U.S. ferret farm. In contrast, the strains shared 82% and 89% nucleotide sequence identities with other ferret HEV that isolated from the Netherlands (JN998607) and the U.S. (AB890374), suggesting that these strains form a novel cluster of ferret HEV with diverse genomes depending on the region where their host. Particles with a diameter of ~35nm at a density of 1.201g/cm were observed in the fecal specimens by electron microscopy. There was no evidence that the particles were associated with the cell membrane. The ferret HEV RNA was not constantly detected in urine, suggesting that the excretion of ferret HEV into urine is not a common feature of HEV infection.
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http://dx.doi.org/10.1016/j.meegid.2017.03.026DOI Listing
July 2017

Abscess of Zygomatic Root: A Rare Otogenic Complication.

Chin Med J (Engl) 2017 Mar;130(6):749-750

Department of Otolaryngology Head and Neck Surgery, Peking University First Hospital, Beijing 100034, China.

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http://dx.doi.org/10.4103/0366-6999.201610DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5358430PMC
March 2017

Versatility of a localized surface plasmon resonance-based gold nanoparticle-alloyed quantum dot nanobiosensor for immunofluorescence detection of viruses.

Biosens Bioelectron 2017 Mar 20;89(Pt 2):998-1005. Epub 2016 Oct 20.

Laboratory of Biotechnology, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan; College of Agriculture, Academic Institute, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan. Electronic address:

Flu infection, caused by the influenza virus, constitutes a serious threat to human lives worldwide. A rapid, sensitive and specific diagnosis is urgently needed for point-of-care treatment and to control the rapid spread of this disease. In this study, an ultrasensitive, rapid and specific localized surface plasmon resonance (LSPR)-induced immunofluorescence nanobiosensor has been developed for the influenza virus based on a gold nanoparticle (AuNP)-induced quantum dot (QD) fluorescence signal. Alloyed quaternary CdSeTeS QDs were synthesized via the hot-injection organometallic route and were subsequently capped with l-cysteine via a ligand exchange reaction. AuNPs were synthesized in HEPES buffer and thiolated with l-cysteine. The concept of the biosensor involves the conjugation of anti-neuraminidase (NA) antibody (anti-NA Ab) to thiolated AuNPs and the conjugation of anti-hemagglutinin (HA) antibody (anti-HA Ab) to alloyed quaternary l-cysteine-capped CdSeTeS QDs. Interaction of the antigens displaying on the surface of the influenza virus target with anti-NA Ab-conjugated AuNPs and anti-HA Ab-conjugated QDs induces an LSPR signal from adjacent AuNPs to trigger fluorescence-enhancement changes in the QDs in proportion to the concentration of the target virus. The detection limit for influenza H1N1 virus was 0.03pg/mL in deionized water and 0.4pg/mL in human serum; while, for the clinically isolated H3N2, the detection limit was 10PFU/mL. The detection of influenza virus H1N1 was accomplished with high sensitivity. The versatility of the biosensor was demonstrated for the detection of clinically isolated influenza virus H3N2 and norovirus-like particles (NoV-LPs).
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http://dx.doi.org/10.1016/j.bios.2016.10.045DOI Listing
March 2017