HLA class Ⅱ alleles in human sporotrichosis in Mexican Amerindians

Human leukocyte antigen (HLA) class Ⅱ alleles are involved in antigen processing and presentation to T lymphocytes during fungal infections. However, few studies have investigated HLA genes in fungal diseases, or in sporotrichosis infections. Here, the frequencies of HLA-DRβ1 in 50 healthy volunteers and 9 patients with sporotrichosis from an endemic area in Mexico were determined to define their role in genetic susceptibility to this infection. Also, the frequencies of HLA-DRβ1 haplotypes were compared with a historic control group of healthy Mexican individuals. The patients presented that DR4 and DR8 increased, which were more than twice the control''s values, whereas local controls (endemic area) presented DR*04:01 increased, compared with the control group from Mexico City. The data suggest that involvement of HLA antigens could affect the outcomes of the host-fungi interaction in sporotrichosis by regulating the immune response to Sporothrix schenckii complex.     

Association of HLA classⅠand classⅡgenes with severe acute respiratory syndrome in the northern Chinese population

Severe acute respiratory syndrome (SARS) was a major epidemic at the beginning of the 21^st century. This highly infectious disease is caused by a novel coronavirus (SARS-CoV), whose immune reaction is still not completely understood. This study described the genetic patterns of HLA-A, -B, and -DRB1 loci in patients from Beijing who survived SARS, and examined whether an association between HLA genes and susceptibility/resistance to SARS exists. A total of 148 Chinese Han SARS survivors were recruited to donate convalescent plasma in 2003. HLA low-resolution genotyping was carried out using PCR-SSP. Allele frequencies were compared with published frequencies of HLA alleles from 11 755 unrelated northern Chinese Han bone marrow donors by Fisher''s exact test. In this cohort, 13, 25 and 13 alleles were observed at HLA-A, -B, and -DRB1 loci respectively. Fisher''s exact tests revealed four alleles (A*26, DRB1*04, DRB1*09, and DRB1*16) that showed a nominal association significance with the SARS virus (P<0.05), yet none of these associations remained significant after correction. Our study suggests that HLA polymorphisms were unlikely to have contributed significantly to either the susceptibility or resistance to the SARS-Cov infection in patients who survived SARS in the Northern Chinese population, thus leaving an open question for future studies into a possible association HLA class Ⅰ and class Ⅱ genes with SARS in patients who were unable to survive the infection.     

ZIKV viral proteins and their roles in virus-host interactions

The re-emergence of Zika virus(ZIKV) and its associated neonatal microcephaly and Guillain-Barré syndrome have led the World Health Organization to declare a global health emergency. Until today, many related studies have successively reported the role of various viral proteins of ZIKVin the process of ZIKVinfection and pathogenicity. These studies have provided significant insights for the treatment and prevention of ZIKV infection. Here we review the current research advances in the functional characterization of the interactions between each ZIKV viral protein and its host factors.     

Anti-Hepatitis B Virus Drugs in Clinical and Preclinical Development

Up to date, there are two types of drugs approved to treat hepatitis B interferons and nucleos (t) ide analogues. However, the therapies are limited in the clinical context because of the negative side effects of interferon-α and the development of substantial viral resistance to nucleos (t) idic inhibitors. Therefore, new drugs with novel structures and mechanisms are needed. In this article, the drugs approved by FDA or the European Commission for treating chronic hepatitis B virus infection, as well as those under clinical trials, and several compounds in preclinical studies are reviewed. Additionally, some potential targets and strategies to combat chronic hepatitis B virus infection are discussed.     

Cloning,expression, and antiviral activity of interferon β from the Chinese microbat,Myotis davidii

Bats are natural reservoir hosts for many viruses that produce no clinical symptoms in bats.Therefore, bats may have evolved effective mechanisms to control viral replication. However, little information is available on bat immune responses to viral infection. Type I interferon(IFN) plays a key role in controlling viral infections. In this study, we report the cloning, expression, and biological activity of interferon β(IFNβ) from the Chinese microbat species, Myotis davidii. We demonstrated the upregulation of IFNB and IFN-stimulated genes in a kidney cell line derived from M. davidii after treatment with poly I:C or infection with Sendai virus. Furthermore, the recombinant IFNβ inhibited vesicular stomatitis virus and bat adenovirus replication in cell lines from two bat species, M. davidii and Rhinolophus sinicus. We provide the first in vitro evidence of IFNβ antiviral activity in microbats, which has important implications for virus interactions with these hosts.     

Human leukocyte antigen-DP loci are associated with the persistent infection of hepatitis B virus in Chinese population

A genome-wide association study recently showed that genetic variants in human leukocyte antigen (HLA)-DP loci were strongly associated with a risk of persistent infection of hepatitis B virus (HBV) in Japanese and Thai individuals and variants in interleukin 28B (IL-28B) have been associated with responses to anti-hepatitis C virus (HCV) treatment. The aim of this study was to investigate whether the HLA-DP loci and IL-28B were associated with different outcomes of chronic HBV infection (CHB) in Chinese subjects. The rs9277535 near HLA-DPB1,rs3077 near HLA-DPA1, and rs12979860 genotype near IL28B were genotyped by direct sequencing in 185 CHB patients and 193 self-limited hepatitis B virus (SLHBV)-infected subjects who recovered from HBV infection. The rs9277535 near HLA-DPB1 was strongly associated with CHB (P=0.0000181, OR=1.905). This association was observed independent of HBV e antigen (HBeAg) status and HBV viral loads in HBeAg-positive patients (P=0.0004, OR=1.956), in HBeAg-negative patients (P=0.0009, OR=1.857), and in HBeAg-negative individuals without detectable levels of HBV DNA in serum (P=0.0011, OR=2.05). The rs3077 near HLA-DPA1 was associated with CHB (P=0.0206, OR=0.6865) and HBeAg-positive infection status (P=0.0143, OR=0.6047). Meanwhile, a genetic variation of insertion-deletion (INDEL) polymorphism (rs361527, -/ATAAATGTTGA) near HLA-DPA1 was found to be associated with CHB (P=0.0307, OR=0.7028) and HBeAg-positive CHB infection status (P=0.0233, OR=0.619). However,the rs12979860 genotype near IL28B had no correlation with CHB. This study demonstrated that in the Han Chinese populations, HLA DP loci, but not IL-28B, was associated with persistence of infection in different outcomes of HBV infected patients; however, the mechanism needs to be further investigated.     

A case of hepatitis B reactivation in an anti-HBs positive, anti-HBc positive non-Hodgkin’s lymphoma patient

Dear Editor, We report a case of HBV reactivation in an anti-HBs positive,anti-HBc positive non-Hodgkin's lymphoma patient.Hepatitis B virus (HBV) reactivation is a well-recognized complication of patients undergoing chemotherapy or immunosuppressive therapy for lymphomas.The presence of antibodies to the hepatitis B surface antigen (anti-HBs) has been identified to be a factor preventing HBV reactivation in patients with occult HBV infection receiving chemotherapy.In this paper,we present a non-Hodgkin Lymphoma patient who,before immunosuppressive therapy,displayed positive anti-HBs and positive antibodies to hepatitis B core antigens (anti-HBc),as markers of resolved HBV infection,and developed hepatitis B surface antigen (HBsAg) and high viraemia with an HBV escape mutant after rituximabbased administration.The sequencing data revealed HBV genotype D with two known escape mutations,P120S.     

Studies on the allostimulatory function of dendritic cells from HCV-HIV-1 co-infected patients

There is increasing recognition of the potential morbidity and mortality associated with HIV- 1 and hepatitis C (HCV) co-infection. HIV appears to adversely affect HCV disease while the reciprocal effect of HCV on HIV remains controversial.We therefore studied the effect of co-infection on dendritic cell function versus HIV infection alone, as previous work has shown that HCV impairs dendritic cell (DC) function. HIV-1 positive individuals with HCV were matched for CD4 count, HIV-1 RNA viral load and therapy, to HIV-1 positive patients without HCV. Monocyte-derived DC were generated and mixed leukocyte reactions were performed. We assessed allostimulatory capacity with and without administration of exogenous Thl cytokines, using thymidine uptake and cell division analyses with the vital dye CFSE. We found that monocyte-derived DC from co-infected individuals showed no significant differences in allostimulatory capacity to ex vivo generated DC from HIV-1 infected individuals without HCV. Unlike the situation with HCV infection alone, this impairment was not reversed by increasing concentrations of either interleukin-2 or -12. Monocyte-derived DC from HIV- 1 and HCV co-infected individuals have a similar allostimulatory capacity to DC from matched patients with HIV-1 alone. These findings are compatible with results of prior clinical studies that found no evidence that HCV co-infection altered HIV disease progression and has implications for immunotherapeutic approaches in co-infected individuals.     

Identification of potential cross-protective epitope between a new type of coronavirus(2019-nCoV) and severe acute respiratory syndrome virus

Recently,a new type of unknown virus causing severe acute res-piratory infection was reported in Wuhan city,Hubei province,China(WHO,2020b).Infection of this virus was first reported in December 2019,and origin of the virus was traced back to a large seafood/wide animal market in Wuhan city.The serious clinical symptoms of the viral infection,including fever,dry cough,dys-pnea,and pneumonia,may result in progressive respiratory failure and even death.Moreover,the quick spread of the virus has caused an epidemic in China,as well as infection cases worldwide.The whole-genome sequence of Wuhan new virus(WH-Human_.1)was first released on January 10,2020(Zhang,2020),followed by additional ones released in Global Initiative on Sharing All Influ-enza Data(GISAID)(Shu and McCauley,2017).Later,this new virus was determined and announced as a new type of coronavirus(CoV;2019-nCoV)by the World Health Organization(WHO,2020a).     

Integrin Activation and Viral Infection

Integrins are members of a ubiquitous membrane receptor family which includes 18 different α subunits and 8 β subunits forming more than 20 α/β heterodimers. Integrins play key functions in vascular endothelial cell and tumour cell adhesion, lymphocyte trafficking, tumor growth and viral infection. Current understanding of the molecular basis of integrins as viral receptors has been achieved through many decades of study into the biology of transmembrane glycoproteins and their interactions with several viruses. This review provides a summary of the current knowledge on the molecular bases of interactions between viruses and integrins, which are of potential practical significance. Inhibition of virus-integrin interactions at the points of virus attachment or entry will provide a novel approach for the therapeutic treatment of viral diseases.     

New Gene Variants Associated with the Risk of Chronic HBV Infection

Some patients with chronic hepatitis B virus(HBV) infection failed to clear HBV, even persistently continue to produce antibodies to HBV. Here we performed a two stage genome wide association study in a cohort of Chinese patients designed to discover single nucleotide variants that associate with HBV infection and clearance of HBV. The first stage involved genome wide exome sequencing of 101 cases(HBsAg plus anti-HBs positive) compared with 102 control patients(antiHBs positive, HBsAg negative). Over 80% of individual sequences displayed 209 sequence coverage. Adapters,uncertain bases [10% or low-quality base calls([50%) were filtered and compared to the human reference genome hg19. In the second stage, 579 chronic HBV infected cases and 439 HBV clearance controls were sequenced with selected genes from the first stage. Although there were no significant associated gene variants in the first stage, two significant gene associations were discovered when the two stages were assessed in a combined analysis. One association showed rs506121-‘‘T' allele [within the dedicator of cytokinesis 8(DOCK8) gene] was higher in chronic HBV infection group than that in clearance group(P = 0.002, OR = 0.77, 95% CI [0.65, 0.91]). The second association involved rs2071676—A allele within the Carbonic anhydrase(CA9) gene that was significantly elevated in chronic HBV infection group compared to the clearance group(P = 0.0003, OR = 1.35, 95% CI [1.15, 1.58]). Upon replication these gene associations would suggest the influence of DOCK8 and CA9 as potential risk genetic factors in the persistence of HBV infection.     

A Chinese perspective on factors and molecular mechanisms that influence the curative effects of platelet transfusion

Platelet transfusion, as the primary treatment for severely low platelet count (thrombocytopenia) or disorders of platelet function, is used extensively in patients with blood system diseases or active hemorrhaging. In recent decades platelet related researches in China have steadily increased. In the clinical application of platelet transfusion, there are large differences between the treatment’s effects on different patients. Immune or nonimmune factors, such as platelet-specific antibodies, platelet gene analysis and matches, and auxiliary treatment, may affect the curative effect, and even result in ineffective platelet transfusion. Platelets used in clinical therapy include platelets made from whole blood and hemapheresis platelets, and the latter is the main application type used in China. Both preparation and preservation methods can affect the quality of platelets and influence the therapeutic effect. Researches on the molecular basis or the curative effect of platelet transfusion are increasing, such as the relationship between platelet-activating factors, tissue factors, thrombopoietin, membrane glycoprotein and platelet activation, and their influence on the curative effect of platelet transfusion, the inhibition of antiplatelet therapy in platelet activation, and platelet signal transduction pathways and their significance in the curative effect of platelet transfusion. This article aims to review the research progress on the curative effect of platelet transfusion and its molecular mechanisms.     

Generation of A Stable GFP-reporter Zika Virus System for High-throughput Screening of Zika Virus Inhibitors

Zika virus(ZIKV) is associated with severe birth defects and Guillain-Barre′ syndrome and no approved vaccines or specific therapies to combat ZIKV infection are currently available. To accelerate anti-ZIKV therapeutics research, we developed a stable ZIKV GFP-reporter virus system with considerably improved GFP visibility and stability. In this system a BHK-21 cell line expressing DC-SIGNR was established to facilitate the proliferation of GFP-reporter ZIKV. Using this reporter virus system, we established a high-throughput screening assay and screened a selected plant-sourced compounds library for their ability to block ZIKV infection. More than 31 out of 974 tested compounds effectively decreased ZIKV reporter infection. Four selected compounds, homoharringtonine(HHT), bruceine D(BD), dihydroartemisinin(DHA) and digitonin(DGT), were further validated to inhibit wild-type ZIKV infection in cells of BHK-21 and human cell line A549.The FDA-approved chronic myeloid leukemia treatment drug HHT and BD were identified as broad-spectrum flavivirus inhibitors. DHA, another FDA-approved antimalarial drug effectively inhibited ZIKV infection in BHK-21 cells. HHT, BD and DHA inhibited ZIKV infection at a post-entry stage. Digitonin was found to have inhibitory activity in the early stage of viral infection. Our research provides an efficient high-throughput screening assay for ZIKV inhibitors. The active compounds identified in this study represent potential therapies for the treatment of ZIKV infection.     

Immediate–Early(IE) gene regulation of cytomegalovirus:IE1-and pp71-mediated viral strategies against cellular defenses

Three crucial hurdles hinder studies on human cytomegalovirus(HCMV): strict species specificity, differences between in vivo and in vitro infection, and the complexity of gene regulation. Ever since the sequencing of the whole genome was first accomplished, functional studies on individual genes have been the mainstream in the CMV field. Gene regulation has therefore been elucidated in a more detailed fashion. However, viral gene regulation is largely controlled by both cellular and viral components. In other words, viral gene expression is determined by the virus–host interaction. Generally, cells respond to viral infection in a defensive pattern; at the same time, viruses try to counteract the cellular defense or else hide in the host(latency). Viruses evolve effective strategies against cellular defense in order to achieve replicative success. Whether or not they are successful, cellular defenses remain in the whole viral replication cycle: entry, immediate–early(IE) gene expression, early gene expression, DNA replication, late gene expression, and viral egress. Many viral strategies against cellular defense, and which occur in the immediate–early time of viral infection, have been documented. In this review, we will summarize the documented biological functions of IE1 and pp71 proteins, especially with regard to how they counteract cellular intrinsic defenses.     

An Integrated Systems Biology Approach Identifies ZIKV and DENV Replication

The Zika virus(ZIKV) and dengue virus(DENV) flaviviruses exhibit similar replicative processes but have distinct clinical outcomes. A systematic understanding of virus–host protein–protein interaction networks can reveal cellular pathways critical to viral replication and disease pathogenesis. Here we employed three independent systems biology approaches toward this goal. First,protein array analysis of direct interactions between individual ZIKV/DENV viral proteins and20,240 human proteins revealed multiple conserved cellular pathways and protein complexes,including proteasome complexes. Second, an RNAi screen of 10,415 druggable genes identified the host proteins required for ZIKV infection and uncovered that proteasome proteins were crucial in this process. Third, high-throughput screening of 6016 bioactive compounds for ZIKV inhibition yielded 134 effective compounds, including six proteasome inhibitors that suppress both ZIKV and DENV replication. Integrative analyses of these orthogonal datasets pinpoint proteasomes as critical host machinery for ZIKV/DENV replication. Our study provides multi-omics datasets for further studies of flavivirus–host interactions, disease pathogenesis, and new drug targets.     

Early Pattern of Epstein-Barr Virus Infection in Gastric Epithelial Cells by “Cell-in-cell”

Epstein-Barr virus(EBV)is an important human dsDNA virus,which has been shown to be associated with several malignancies including about 10%of gastric carcinomas.How EBV enters an epithelial cell has been an interesting project for investigation."Cell-in-cell"infection was recently reported an efficient way for the entry of EBV into nasopharynx epithelial cells.The present approach was to explore the feasibility of this mode for EBV infection in gastric epithelial cells and the dynamic change of host inflammatory reaction.The EBV-positive lymphoblastic cells of Akata containing a GFP tag in the viral genome were co-cultured with the gastric epithelial cells(GES-1).The infection situation was observed under fluorescence and electron microscopies.Real-time quantitative PCR and Western-blotting assay were employed to detect the expression of a few specific cytokines and inflammatory factors.The results demonstrated that EBV could get into gastric epithelial cells by"cell-in-cell"infection but not fully successful due to the host fighting.IL-1β,IL-6 and IL-8 played prominent roles in the cellular response to the infection.The activation of NF-κB and HSP70 was also required for the host antiviral response.The results imply that the gastric epithelial cells could powerfully resist the virus invader via cell-in-cell at the early stage through inflammatory and innate immune responses.