2020 Vol.35(5)
Dengue virus (DENV) is an important mosquito borne-flavivirus that causes dengue fever and in some heterotypic secondary infections, haemorrhagic symptoms that might risk the lives of patients. These epidemiologic observations were made 50 years ago, suggest that the previous immune response to DENV could be involved in the pathology of the disease. Nowadays, it has been shown that the DENV specific antibodies are participating through a mechanism called antibody-dependent enhancement (ADE). The cellular bases of how these antibodies are generated in secondary lymphoid organs remain largely unexplored. In this issue, Marcial-Juárez et al., demonstrated massive B cell proliferation inside regional lymph node follicles after cutaneous DENV immunization in mice and, contrastingly, a very poor T cell response. The cover image shows a panoramic view of a lymph node, with intense recruitment of tingle-body macrophages (TBMs, green) inside DENV-induced germinal centers (IgD [red]-negative areas in the cortex) to remove the large number of apoptotic bodies present in regional lymph node follicles. Please see 575-587 pages for details.
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A Comprehensive Review on Human Aichi Virus
2020, 35(5): 501 doi: 10.1007/s12250-020-00222-5
Received: 21 September 2019
Accepted: 28 February 2020
Published: 27 April 2020
Although norovirus, rotavirus, adenovirus and Astrovirus are considered the most important viral agents transmitted by food and water, in recent years other viruses, such as Aichi virus (AiV), have emerged as responsible for gastroenteritis outbreaks associated with different foods. AiV belongs to the genus Kobuvirus of the family Picornaviridae. It is a virus with icosahedral morphology that presents a single stranded RNA genome with positive sense (8280 nucleotides) and a poly (A) chain. AiV was first detected from clinical samples and in recent years has been involved in acute gastroenteritis outbreaks from different world regions. Furthermore, several studies conducted in Japan, Germany, France, Tunisia and Spain showed a high prevalence of AiV antibodies in adults (between 80% and 99%), which is indicative of a large exposure to this virus. The aim of this review is to bring together all the discovered information about the emerging pathogen human Aichi virus (AiV), discussing the possibles routes of transmission, new detection techniques and future research. Although AiV is responsible for a low percentage of gastroenteritis outbreaks, the high seroprevalence shown by human populations indicates an evident role as an enteric agent. The low percentage of AiV detection could be explained by the fact that the pathogen is more associated to subclinical infections. Further studies will be needed to clarify the real impact of AiV in human health and its importance as a causative gastroenteritis agent worldwide.
Isolation and Characterization of A Novel Fowl Adenovirus Serotype 8a Strain from China
2020, 35(5): 517 doi: 10.1007/s12250-019-00172-7
Received: 04 June 2019
Accepted: 05 August 2019
Published: 02 December 2020
Since 2012, the clinical cases of inclusion body hepatitis showed an increasing trend in China, causing considerable economic losses to the poultry industry. In this study, a fowl adenovirus strain CH/GDLZ/201801 was isolated from a chicken flock experiencing inclusion body hepatitis and analyzed by complete genome sequencing. The pathogenicity of the new virus strain was examined by experimental infection of specific pathogen free chickens. The isolate was identified by immunofluorescence and the virions presented typical icosahedral particles under transmission electron microscopy. The full genome of the isolate was 44, 329 nucleotides in length with 58% G+C content. Phylogenetic analysis, based on the whole genome, revealed that the new isolate was closest to serotype 8a from the species Fowl aviadenovirus E (FAdV-E). Recombination analysis and phylogenetic analysis showed that the new isolate is a recombinant strain between FAdV-8a and FAdV-8b. In infection experiments, three infected chickens showed clinical signs and one chicken died on day 7 post infection, corresponding to 5% mortality. Macroscopic and microscopic lesions in the liver were observed, and viral antigen could be detected in the livers by immunohistochemical staining and TEM. Taken together, our study describes the genomic characteristics and pathogenicity of a FAdV-8a strain in China. It would lay a solid foundation for further study of the pathogenic mechanism and vaccine development of the virus.
Characterization of the First Genome of Porcine mastadenovirus B (HNU1 Strain) and Implications on Its Lymphoid and Special Origin
2020, 35(5): 528 doi: 10.1007/s12250-020-00210-9
Received: 05 December 2019
Accepted: 04 February 2020
Published: 31 March 2020
Porcine adenoviruses (PAdVs) are classified into three species, PAdV-A, PAdV-B, and PAdV-C. The genomes of PAdV-A and PAdV-C have been well characterized. However, the genome of PAdV-B has never been completely sequenced, and the epidemiology of PAdV-B remains unclear. In our study, we have identified a novel strain of PAdV-B, named PAdV-B-HNU1, in porcine samples collected in China by viral metagenomic assay and general PCR. The genome of PAdV-B-HNU1 is 31, 743 bp in length and highly similar to that of California sea lion adenovirus 1 (C. sea lion AdV-1), which contains typical mastadenoviral structures and some unique regions at the carboxy-terminal end. Especially, PAdV-B-HNU1 harbors a dUTPase coding region not clustering with other mastadenoviruses except for C. sea lion AdV-1 and a fiber coding region homologous with galectin 4 and 9 of animals. However, the variance of GC contents between PAdV-B-HNU1 (55%) and C. sea lion AdV-1 (36%) indicates their differential evolutionary paths. Further epidemiologic study revealed a high positive rate (51.7%) of PAdV-B-HNU1 in porcine lymph samples, but low positive rates of 10.2% and 16.1% in oral swabs and rectal swabs, respectively. In conclusion, this study characterized a novel representative genome of a lymphotropic PAdV-B with unique evolutionary origin, which contributes to the taxonomical and pathogenic studies of PAdVs.
Laos is Affected by HIV CRF01_AE and the Newly Identified CRF97_01B
2020, 35(5): 538 doi: 10.1007/s12250-020-00215-4
Received: 02 December 2019
Accepted: 18 February 2020
Published: 30 March 2020
Laos is the only landlocked country in Southeast Asia and borders Thailand, Myanmar and Cambodia, the three countries in this region that have been hardest hit by human immunodeficiency virus (HIV). Laos has been regarded as a low-HIV-prevalence country for decades. To understand the status of HIV in Laos in recent years, a retrospective study was performed among 2851 patients visiting a hospital in Vientiane, the capital of Laos, from November 2011 to May 2012. Whole blood samples were obtained from the patients, and DNA was extracted. HIV status was determined by HIV gag fragment-specific PCR assay. Sixty-nine samples were detected as HIV proviral DNA positive with a positive rate of 2.4% (69/2851). Sixty-one near full-length genomic sequences were obtained from the positive samples. The results of phylogenetic analysis showed that the vast majority (91.8%) of the HIV strains belonged to CRF01_AE, and the other five (8.2%) strains were identified as a new HIV circulating recombinant form CRF97_01B, which had a CRF01_AE backbone with an insertion of subtype B in the gag-pol region. Phylogeographic analysis revealed that HIV CRF01_AE circulating in Laos were multiply introduced from Thailand. These results indicated that Laos might be suffering a considerably more serious impact of HIV than previously believed. To keep this country from undergoing the same increase in HIV prevalence observed in its neighbors, immediate intervention measures and sufficient epidemiological research are urgently needed.
Phylogeography of Highly Pathogenic H5 Avian Influenza Viruses in China
2020, 35(5): 548 doi: 10.1007/s12250-020-00193-7
Received: 26 May 2019
Accepted: 17 December 2020
Published: 08 May 2020
The spread of H5 highly pathogenic avian influenza viruses poses serious threats to the poultry industry, wild bird ecology and human health. Circulation of H5 viruses between poultry and wild birds is a significant public health threat in China. Thus, viral migration networks in this region need to be urgently studied. Here, we conducted molecular genetic analyses of the hemagglutinin genes of H5 highly pathogenic avian influenza viruses in multiple hosts from 2000 to 2018 in China. Our aim was to clarify the roles of different hosts in the evolution of H5 viruses. We used a flexible Bayesian statistical framework to simulate viral space diffusion and continuous-time Markov chains to infer the dynamic evolutionary process of spatiotemporal dissemination. Bayesian phylogeographic analysis of H5 viruses showed for the first time that H5 viruses in poultry and wild birds were present in Guangdong Province. Furthermore, Guangdong, Jiangsu, Shanghai and Hunan acted as the epicenters for the spread of various H5 subtypes viruses in poultry, and Henan, Shanghai, Hong Kong and Inner Mongolia acted as epicenters for the spread of various H5 subtypes viruses in wild birds. Thus, H5 viruses exhibited distinct evolutionary dynamics in poultry and wild birds. Our findings extend our understanding of the transmission and spread of highly pathogenic H5 avian influenza viruses in China.
Molecular Epidemiology and Vaccine Compatibility Analysis of Seasonal Influenza Viruses in Wuhan, 2016–2019
2020, 35(5): 556 doi: 10.1007/s12250-020-00225-2
Received: 15 December 2019
Accepted: 07 March 2020
Published: 11 May 2020
Influenza viruses (FLUV) cause high morbidity and mortality annually in the world and pose a serious threat to the public health. Wuhan, as an important transportation hub in China, has a dense population and suitable climate, which also lays a major hidden danger for the outbreak of influenza. To survey and characterize the seasonal FLUV in Wuhan during 2016–2019, we collected 44, 738 throat swabs, among which 15.5% were influenza A (FLUAV) positive, 6.1% influenza B (FLUBV) and 0.3% co-infection. By monitoring FLUV in each month from June 2016 to May 2019, different with the previously seasonality pattern, only a single influenza peak was appeared in winter of 2017–2018 and 2018–2019, respectively. These data indicated that the complex circulation pattern of seasonal influenza in Wuhan. In addition, we found the age group was skewed towards 5–14 years group whose activity were mostly school based, which suggested school may be an important place for influenza outbreaks. Meanwhile, phylogenic analysis revealed that two subtypes (subclade 3C.2a2 and 3C.2a1b) of A(H3N2) were circulating in Wuhan and there was an obvious transition in 2018 because the two subclades were detected simultaneously. Furthermore, by estimating the vaccine effectiveness, we found that the vaccine strain of FLUAV didn't seem to match very well the current epidemic strain, especially A(H3N2). Hence, more accurate prediction of seasonal outbreak is essential for vaccine design. Taken together, our results provided the current information about seasonal FLUV in Wuhan which form the basis for vaccine updating.
Effect of Peroxisome Proliferator-Activated Receptor-γ Coactivator-1 Alpha Variants on Spontaneous Clearance and Fibrosis Progression during Hepatitis C Virus Infection in Moroccan Patients
2020, 35(5): 566 doi: 10.1007/s12250-020-00220-7
Received: 04 October 2019
Accepted: 08 February 2020
Published: 15 April 2020
Hepatitis C virus (HCV) is still one of the main causes of liver disease worldwide. Metabolic disorders, including non-alcoholic fatty liver disease (NAFLD), induced by HCV have been shown to accelerate the progression of fibrosis to cirrhosis and to increase the risk of hepatocellular carcinoma. An optimal peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) activity is crucial to prevent NAFLD installation. The present study aims to investigate the associations between two common PPARGC1A polymorphisms (rs8192678 and rs12640088) and the outcomes of HCV infection in a North African context. A series of 592 consecutive Moroccan subjects, including 292 patients with chronic hepatitis C (CHC), 100 resolvers and 200 healthy controls were genotyped using a TaqMan allelic discrimination assay. PPARGC1A variations at rs8192678 and rs12640088 were not associated with spontaneous clearance of HCV infection (adjusted ORs = 0.76 and 0.79 respectively, P > 0.05, for both). Furthermore, multivariable logistic regression analysis showed that both SNPs were not associated with fibrosis progression (OR = 0.71; 95% CI 0.20–2.49; P = 0.739; OR = 1.28; 95% CI 0.25–6.54; P = 0.512, respectively). We conclude that, in the genetic context of South Mediterranean patients, rs8192678 and rs12640088 polymorphisms of PPARGC1A are neither associated with spontaneous clearance nor with disease progression in individuals infected with HCV.
Cutaneous Dengue Virus Inoculation Triggers Strong B Cell Reactions but Contrastingly Poor T Cell Responses
2020, 35(5): 575 doi: 10.1007/s12250-020-00213-6
Received: 16 October 2019
Accepted: 24 December 2019
Published: 20 April 2020
Dengue is a global health problem without current specific treatment nor safe vaccines available. While severe dengue is related to pre-existing non-neutralizing dengue virus (DENV) antibodies, the role of T cells in protection or pathology is unclear. Using cutaneous DENV infection in immunocompetent mice we previously showed the generation of PNA+ germinal centers (GCs), now we assessed the activation and proliferation of B and T cells in draining lymph nodes (DLNs). We found a drastic remodelling of DLN compartments from 7 to 14 days post-infection (dpi) with greatly enlarged B cell follicles, occupying almost half of the DLN area compared to ~24% in naïve conditions. Enormous clusters of proliferating (Ki-67+) cells inside B follicles were found 14 dpi, representing ~33% of B cells in DLNs but only ~2% in non-infected mice. Inside GCs, we noticed an important recruitment of tingle body macrophages removing apoptotic cells. In contrast, the percentage of paracortex area and total T cells decreased by 14–16 dpi, compared to controls. Scattered randomly distributed Ki-67+ T cells were found, similar to non-infected mice. CD69 expression by CD4+ and CD8+ T cells was minor, while it was remarkable in B cells, representing 1764.7% of change from basal levels 3 dpi. The apparent lack of T cell responses cannot be attributed to apoptosis since no significant differences were observed compared to non-infected mice. This study shows massive B cell activation and proliferation in DLNs upon DENV infection. In contrast, we found very poor, almost absent CD4+ and CD8+ T cell responses.
Depletion but Activation of CD56dimCD16+ NK Cells in Acute Infection with Severe Fever with Thrombocytopenia Syndrome Virus
2020, 35(5): 588 doi: 10.1007/s12250-020-00224-3
Received: 11 August 2019
Accepted: 28 February 2020
Published: 19 May 2020
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high mortality (12%–30%). The mechanism by which the SFTS bunyavirus (SFTSV) causes severe illness remains unclear. To evaluate the phenotypic and functional characteristics of the NK cell subsets in SFTS patients, twenty-nine SFTS patients were sequentially sampled from admission until recovery. Phenotypic and functional characteristics of NK cell subsets in circulating blood were analysed via flow cytometry. Then, correlations between NK cell subset frequencies and the SFTS index (SFTSI) were evaluated in all SFTS patients (15 mild, 14 severe) upon admission. The frequencies of CD56dimCD16+ NK cells were greatly decreased in early SFTSV infection and were negatively correlated with disease severity. Additionally, higher Ki-67 and granzyme B expression and relatively lower NKG2A expression in CD56dimCD16+ NK cells were observed in acute infection. Moreover, the effector function of CD56dim NK cells was increased in the acute phase compared with the recovery phase in nine severe SFTS patients. Additionally, interleukin (IL)-15, interferon (IFN)-α, IL-18 and IFN-γ secretion was markedly increased during early infection. Collectively, despite depletion of CD56dimCD16+ NK cells, activation and functional enhancement of CD56dimCD16+ NK cells were still observed, suggesting their involvement in defence against early SFTSV infection.
Myristoylation of EV71 VP4 is Essential for Infectivity and Interaction with Membrane Structure
2020, 35(5): 599 doi: 10.1007/s12250-020-00226-1
Received: 12 December 2019
Accepted: 03 March 2020
Published: 12 May 2020
The Enterovirus 71 (EV71) VP4 is co-translationally linked to myristic acid at its amino-terminal glycine residue. However, the role of this myristoylation in the EV71 life cycle remains largely unknown. To investigate this issue, we developed a myristoylation-deficient virus and reporter (luciferase) pseudovirus with a Gly-to-Ala mutation (G2A) on EV71 VP4. When transfecting the EV71-G2A genome encoding plasmid in cells, the loss of myristoylation on VP4 did not affect the expression of viral proteins and the virus morphology, however, it did significantly influence viral infectivity. Further, in myristoylation-deficient reporter pseudovirus-infected cells, the luciferase activity and viral genome RNA decreased significantly as compared to that of wild type virus; however, cytopathic effect and viral capsid proteins were not detected in myristoylation-deficient virus-infected cells. Also, although myristoylation-deficient viral RNA and proteins were detected in the second blind passage of infection, they were much fewer in number compared to that of the wild type virus. The replication of genomic RNA and negative-strand viral RNA were both blocked in myristoylation-deficient viruses, suggesting that myristoylation affects viral genome RNA release from capsid to cytoplasm. Besides, loss of myristoylation on VP4 altered the distribution of VP4-green fluorescent protein protein, which disappeared from the membrane structure fraction. Finally, a liposome leakage assay showed that EV71 myristoylation mediates the permeability of the model membrane. Hence, the amino-terminal myristoylation of VP4 is pivotal to EV71 infection and capsid-membrane structure interaction. This study provides novel molecular mechanisms regarding EV71 infection and potential molecular targets for antiviral drug design.
IP10, KC and M-CSF Are Remarkably Increased in the Brains from the Various Strains of Experimental Mice Infected with Different Scrapie Agents
2020, 35(5): 614 doi: 10.1007/s12250-020-00216-3
Received: 17 September 2019
Accepted: 27 November 2019
Published: 20 April 2020
Activation of inflammatory cells and upregulations of a number of cytokines in the central nervous system (CNS) of patients with prion diseases are frequently observed. To evaluate the potential changes of some brain cytokines that were rarely addressed during prion infection, the levels of 17 different cytokines in the brain homogenates of mice infected with different scrapie mouse-adapted agents were firstly screened with Luminex assay. Significant upregulations of interferon gamma-induced protein 10 (IP10), keratinocyte chemoattractant (KC) and macrophage colony stimulating factor (M-CSF) were frequently detected in the brain lysates of many strains of scrapie infected mice. The upregulations of those three cytokines in the brains of scrapie infected mice were further validated by the individual specific ELISA and immunohistochemical assay. Increased specific mRNAs of IP10, M-CSF and KC in the brains of scrapie infected mice were also detected by the individual specific qRT-PCRs and IP10-specific digital PCR. Dynamic analyses of the brain samples collected at different time points post infection revealed the time-dependent increases of those three cytokines, particularly IP10 during the incubation period of scrapie infection. In addition, we also found that the levels of IP10 in cerebral spinal fluid (CSF) of 45 sporadic Creutzfeldt–Jakob disease (sCJD) patients were slightly but significantly higher than those of the cases who were excluded the diagnosis of prion diseases. These data give us a better understanding of inflammatory reaction during prion infection and progression of prion disease.
Establishment of Murine Infection Models with Biological Clones of Dengue Viruses Derived from a Single Clinical Viral Isolate
2020, 35(5): 626 doi: 10.1007/s12250-020-00229-y
Received: 09 November 2019
Accepted: 11 March 2020
Published: 25 May 2020
Dengue virus (DENV) is a single-stranded RNA virus transmitted by mosquitoes in tropical and subtropical regions. It causes dengue fever, dengue hemorrhagic fever and dengue shock syndrome in patients. Each year, 390 million people are estimated to be infected by four serotypes of dengue virus, creating a great burden on global public health and local economy. So far, no antiviral drug is available for dengue disease, and the newly licensed vaccine is far from satisfactory. One large obstacle for dengue vaccine and drug development is the lack of suitable small animal models. Although some DENV infection models have been developed, only a small number of viral strains can infect immunodeficient mice. In this study, with biologically cloned viruses from a single clinical isolate, we have established two mouse models of DENV infection, one is severe lethal infection in immunocompromised mice, and the other resembles self-limited disease manifestations in Balb/c mice with transient blockage of type Ⅰ IFN responses. This study not only offers new small animal models of dengue viral infection, but also provides new viral variants for further investigations on dengue viral pathogenesis.
Baculovirus Surface Display of Zika Virus Envelope Protein Protects against Virus Challenge in Mouse Model
2020, 35(5): 637 doi: 10.1007/s12250-020-00238-x
Received: 24 October 2019
Accepted: 10 April 2020
Published: 29 May 2020
Zika virus (ZIKV) is emerging as a significant pathogen worldwide and may cause severe neurological disorders such as fetal microcephaly and Guillain-Barre syndrome. No drug or listed vaccines are currently available for preventing ZIKV infection. As a major target of neutralizing, ZIKV envelop (E) protein usually used for vaccine development. Nevertheless, the immunogenicity of ZIKV envelop (E) protein expressed by baculovirus display system has never been assessed. In this study, we reported a new strategy for surface display of ZIKV E protein by a recombinant baculovirus vector derived from Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) and assessed its immunogenicity in mice. We produced recombinant fusion ZIKV E protein linked with signal peptide (SP) and transmembrane domain (TM) of AcMNPV GP64. The results showed that the recombinant protein was easy to produce by baculovirus display system. BALB/c mice immunized with this recombinant E protein developed ZIKV specific serum antibodies. The anti-E protein sera from the mice were able to effectively neutralize ZIKV in vitro. More importantly, AG6 (IFN-α/β and IFN-γ receptor deficient) mice immunized with recombinant E protein were protected against lethal ZIKV challenge. Together, these findings demonstrated that the recombinant E protein displayed by baculovirus can be conveniently prepared and displayed good immunogenicity in immunized mice. It is a promising practical approach for prompting the development of vaccine and related immunology research.
Recombination of T4-like Phages and Its Activity against Pathogenic Escherichia coli in Planktonic and Biofilm Forms
2020, 35(5): 651 doi: 10.1007/s12250-020-00233-2
Received: 09 October 2019
Accepted: 10 March 2020
Published: 25 May 2020
The increasing emergence of multi-drug resistant Escherichia coli (E. coli) has become a global concern, primarily due to the limitation of antimicrobial treatment options. Phage therapy has been considered as a promising alternative for treating infections caused by multi-drug resistant E. coli. However, the application of phages as a promising antimicrobial agent is limited by their narrow host range and specificity. In this research, a recombinant T4-like phage, named WGqlae, has been obtained by changing the receptor specificity determinant region of gene 37, using a homologous recombination platform of T4-like phages established by our laboratory previously. The engineered phage WGqlae can lyse four additional hosts, comparing to its parental phages WG01 and QL01. WGqlae showed similar characteristics, including thermo and pH stability, optimal multiplicity of infection and one-step growth curve, to the donor phage QL01. In addition, sequencing results showed that gene 37 of recombinant phage WGqlae had genetically stable even after 20 generations. In planktonic test, phage WGqlae had significant antimicrobial effects on E. coli DE192 and DE205B. The optical density at 600 nm (OD600) of E. coli in phage WGqlae treating group was significantly lower than that of the control group (P < 0.01). Besides, phage WGqlae demonstrated an obvious inhibitory effect on the biofilm formation and the clearance of mature biofilms. Our study suggested that engineered phages may be promising candidates for future phage therapy applications against pathogenic E. coli in planktonic and biofilm forms.
Pan-Genomic Analysis of African Swine Fever Virus
2020, 35(5): 662 doi: 10.1007/s12250-019-00173-6
Received: 10 September 2019
Accepted: 17 October 2019
Published: 11 November 2019
Development of an MCA-Based Real Time RT-qPCR Assay for the Simultaneous Detection and Differentiation of Duck Hepatitis A Virus Types 1 and 3
2020, 35(5): 666 doi: 10.1007/s12250-020-00211-8
Received: 16 October 2019
Accepted: 03 March 2020
Published: 08 April 2020
Correction to: Establishment of Murine Infection Models with Biological Clones of Dengue Viruses Derived from A Single Clinical Viral Isolate
2020, 35(5): 670 doi: 10.1007/s12250-020-00303-5
Published: 30 September 2020
