Retromer localizes to autophagosomes during HCV replication

<正>Dear Editor,Hepatitis C virus(HCV)is a positive-strand RNA virus that belongs to the genus Hepacivirus within the Flaviviridae family.HCV causes chronic liver diseases,and185 million people are infected(Messina et al.,2015).Currently,there is no approved vaccine to prevent hepatitis C.HCV induces autophagy through elevating reactive oxygen species(ROS)levels via the unfolded     

Antigenicity of severe fever with thrombocytopenia syndrome virus nucleocapsid protein and its potential application in the virus serodiagnosis

<正>Dear Editor,Severe fever with thrombocytopenia syndrome virus(SFTSV)is a newly identified viral pathogen of the genus Phlebovirus in the family Bunyaviridae(Sun et al.,2012).SFTSV was first identified from patient serum samples in China(Li et al.,2013;Ning et al.,2015).SFTSV can cause a severe hemorrhagic fever-like disease with a reported case fatality rate ranging from 2.5%     

Isolation and phylogenetic study of Rift Valley fever virus from the first imported case to China

<正>Dear Editor,Rift Valley fever(RVF)is an anthropozoonosis caused by Rift Valley fever virus(RVFV).RVFV belongs to the Phlebovirus genus in the family Bunyaviridae,which is circulating among ruminants.Human infection with RVFV is generally asymptomatic,however,minority of patients develop severe RVF diseases like encephalitis or     

Characterization of a recombinant Akabane mutant virus with knockout of a nonstructural protein NSs in a pregnant goat model

正Dear Editor,Akabane virus(AKAV),an orthobunyavirus,is transmitted primarily by biting midges and is widely distributed throughout the world except the Europe.AKAV was first isolated from mosquitoes in Japan(Oya et al.,1961).Although pregnant cows,ewes,and goats infected with AKAV exhibit no clinical signs of disease,in utero infections result in abortion,premature birth,stillbirth,and     

Construction of an infectious cDNA clone of Tembusu virus isolated from breeder Peking ducks

正Dear Editor,Since April 2010,an outbreak of a new disease has elicited symptoms of high fever,loss of appetite,and reduction in egg production in layer ducks in eastern China;this phenomenon has now spread throughout China(Cao et al.,2011;Su et al.,2011).The causative agent of the disease was identified as Tembusu virus(TMUV),which was classified into the genus Flavivirus,     

Zika virus and Zika fever

An emerging mosquito-borne arbovirus named Zika virus (ZIKV), of the family Flaviviridae and genus Flavivirus, is becoming a global health threat. ZIKV infection was long neglected due to its sporadic nature and mild symptoms. However, recently, with its rapid spread from Asia to the Americas, affecting more than 30 countries, accumulating evidences have demonstrated a close association between infant microcephaly and Zika infection in pregnant women. Here, we reviewed the virological, epidemiological, and clinical essentials of ZIKV infection.

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CD95-CD95L interaction mediates the growth control of MHV68 immortalized B cells by cytotoxic T cells

<正>Dear Editor,The main limitation of the viral pathogenesis study of human gammaherpesviruses Epstein-Barr virus(EBV)and Kaposi sarcoma-associated herpesvirus(KSHV)is the absence of animal model owing to the narrow host tropism of both EBV and KSHV.Murine gammaherpesvirus 68(MHV68)encodes several genes involved in     

Recombinant canarypox virus expressing the VP2 protein of infectious bursal disease virus induces protection in vaccinated SPF chickens

正Dear Editor,Infectious bursal disease virus(IBDV)causes infectious bursal disease,a highly contagious immunosuppressive disease that affects young chickens and causes economic losses in the poultry industry worldwide.IBDV replicates mainly in actively dividing B lymphocytes within the bursa of Fabricius(BF),leading to immunosuppression in affected flocks(Mahgoub et al.,2012).Viral protein 2(VP2),the only structural component of the IBDV     

Molecular typing of non-polio enteroviruses isolated from acute flaccid paralysis cases in Iran from 2010 to 2015

<正>Dear Editor,Acute flaccid paralysis(AFP)is a complex syndrome often caused by polioviruses.While most countries have eradicated wild polioviruses by vaccination,AFP still remains a health problem in these countries.Most studies have highlighted non-polio enteroviruses(NPEVs)as     

Hantavirus infection: a global zoonotic challenge

Hantaviruses are comprised of tri-segmented negative sense single-stranded RNA, and are members of the Bunyaviridae family. Hantaviruses are distributed worldwide and are important zoonotic pathogens that can have severe adverse effects in humans. They are naturally maintained in specific reservoir hosts without inducing symptomatic infection. In humans, however, hantaviruses often cause two acute febrile diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). In this paper, we review the epidemiology and epizootiology of hantavirus infections worldwide.

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Interplay between hepatitis C virus and ARF4

<正>Dear Editor,Hepatitis C virus(HCV)is a major cause of chronic liver diseases and hepatocellular carcinoma(HCC)with about71 million people globally infected.HCV encodes only10 viral proteins and its replication relies on host proteins.Many host factors including ADP-ribosylation factors     

Recent advances in the identification of the host factors involved in dengue virus replication

Dengue virus (DENV) belongs to the genus Flavivirus of the family Flaviviridae and it is primarily transmitted via Aedes aegypti and Aedes albopictus mosquitoes. The life cycle of DENV includes attachment, endocytosis, protein translation, RNA synthesis, assembly, egress, and maturation. Recent researches have indicated that a variety of host factors, including cellular proteins and microRNAs, positively or negatively regulate the DENV replication process. This review summarizes the latest findings (from 2014 to 2016) in the identification of the host factors involved in the DENV life cycle and Dengue infection.

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The V1 region of gp120 is preferentially selected during SIV/HIV transmission and is indispensable for envelope function and virus infection

A transmission bottleneck occurs during each human immunodeficiency virus(HIV) transmission event, which allows only a few viruses to establish new infection. However, the genetic characteristics of the transmitted viruses that are preferentially selected have not been fully elucidated. Here, we analyzed amino acids changes in the envelope protein during simian immunodeficiency virus(SIV)/HIV deep transmission history and current HIV evolution within the last 15–20 years. Our results confirmed that the V1V2 region of gp120 protein, particularly V1, was preferentially selected. A shorter V1 region was preferred during transmission history, while during epidemic, HIV may evolve to an expanded V1 region gradually and thus escape immune recognition. We then constructed different HIV-1 V1 mutants using different HIV-1 subtypes to elucidate the role of the V1 region in envelope function. We found that the V1 region, although highly variable, was indispensable for virus entry and infection, probably because V1 deletion mutants exhibited impaired processing of gp160 into mature gp120 and gp41. Additionally, the V1 region affected Env incorporation. These results indicated that the V1 region played a critical role in HIV transmission and infection.     

Stability of HIV-1 subtype B and C Tat is associated with variation in the carboxyl-terminal region

The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but research on subtype C Tat is lacking, despite the high prevalence of infections caused by subtype C worldwide. We hypothesized that amino acid differences contribute to functional differences among Tat proteins. In the present study, we found that subtype B NL4-3Tat and subtype C isolate HIV1084 i Tat exhibited differences in stability by overexpressing the fusion protein Tat-Flag. In addition, 1084 i Tat can activate LTR and NF-κB more efficiently than NL4-3 Tat. In analyses of the activities of the truncated forms of Tat, we found that the carboxylterminal region of Tat regulates its stability and transactivity. According to our results, we speculated that the differences in stability between B-Tat and C-Tat result in differences in transactivation ability.     

Progress towards understanding the pathogenesis of dengue hemorrhagic fever

Dengue virus (DENV) is a mosquito-borne virus belonging to the Flaviviridae family. There are 4 serotypes of DENV that cause human disease through transmission by mosquito vectors. DENV infection results in a broad spectrum of clinical symptoms, ranging from mild fever to dengue hemorrhagic fever (DHF), the latter of which can progress to dengue shock syndrome (DSS) and death. Researchers have made unremitting efforts over the last half-century to understand DHF pathogenesis. DHF is probably caused by multiple factors, such as virus-specific antibodies, viral antigens and host immune responses. This review summarizes the current progress of studies on DHF pathogenesis, which may provide important information for achieving effective control of dengue in the future.

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A new strain of Crimean-Congo hemorrhagic fever virus isolated from Xinjiang,China

Crimean-Congo hemorrhagic fever virus (CCHFV) is a highly pathogenic tick-borne virus with a fatality rate of up to 50% in humans. CCHFV is widely distributed in countries around the world. Outbreaks of CCHFV infection in humans have occurred in prior years in Xinjiang Province, China. Epidemiological surveys have detected CCHFV RNA in ticks and animals; however, few isolates were identified. In this study, we identified and isolated a new CCHFV strain from Hyalomma asiaticum asiaticum ticks collected from north of Tarim Basin in Xinjiang, China. A preliminary investigation of infection and antigens expression of CCHFV was performed in newborn mice. The target tissues for CCHFV replication in newborn mice were identified. The analysis of the phylogenetic relationships with other Chinese strains suggested that diverse genotypes of CCHFV have circulated in Xinjiang for years. These findings provide important insights into our understanding of CCHFV infection and evolution as well as disease prevention and control for local residents.

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Identification of interaction between HIV-1 glycoprotein 41 and integrase

Human immunodeficiency virus-1(HIV-1) encodes 15 viral proteins. Protein-protein interactions play a large role in the function of these proteins. In this study, we attempted to identify novel interactions between the HIV-1 proteins to better understand the role played by viral protein-protein interactions in the life cycle of HIV-1. Genes encoding the 15 viral proteins from the HIV-1 strain AD8 were inserted into the plasmids of a yeast two-hybrid system. By screening 120 pairs of proteins, interactions between seven pairs were found. This led to the discovery of an interaction between the HIV-1 proteins integrase(IN) and glycoprotein 41(gp41), which was confirmed by both co-immunoprecipitation(Co-IP) assays and fluorescence resonance energy transfer(FRET)imaging in live cells. In addition, it was found that the amino acids at positions 76–100 of gp41 are required for it to bind to IN. Deletion of this region from gp41 prevented its interaction with IN and reduced the production of HIV-1 in 293 T cells. This study provides new information on HIV-1protein-protein interactions which improves the understanding of the biological functions of gp41 and IN during the virus life cycle.     

Recent advances in synthetic carbohydrate-based human immunodeficiency virus vaccines

An effective vaccine for human immunodeficiency virus (HIV) is urgently needed to prevent HIV infection and progression to acquired immune deficiency syndrome (AIDS). As glycosylation of viral proteins becomes better understood, carbohydrate-based antiviral vaccines against special viruses have attracted much attention. Significant efforts in carbohydrate synthesis and immunogenicity research have resulted in the development of multiple carbohydrate-based HIV vaccines. This review summarizes recent advances in synthetic carbohydrate-based vaccines design strategies and the applications of these vaccines in the prevention of HIV.

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Three-dimensional cell culture models for investigating human viruses

Three-dimensional (3D) culture models are physiologically relevant, as they provide reproducible results, experimental flexibility and can be adapted for high-throughput experiments. Moreover, these models bridge the gap between traditional two-dimensional (2D) monolayer cultures and animal models. 3D culture systems have significantly advanced basic cell science and tissue engineering, especially in the fields of cell biology and physiology, stem cell research, regenerative medicine, cancer research, drug discovery, and gene and protein expression studies. In addition, 3D models can provide unique insight into bacteriology, virology, parasitology and host-pathogen interactions. This review summarizes and analyzes recent progress in human virological research with 3D cell culture models. We discuss viral growth, replication, proliferation, infection, virus-host interactions and antiviral drugs in 3D culture models.

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