White spot syndrome virus envelope protein VP124 involved in the virus infection

White spot syndrome virus （WSSV） is one of the major shrimp pathogens causing large economic losses to shrimp farming. In an attempt to identify the envelope proteins involved in the virus infection, purified WSSV virions were mixed with three antisera against WSSV envelope proteins （VP39, VP124 and VP187 ）, individually. And then they were injected intramuscularly into crayfish （Procambarus clarkii） to conduct in vivo neutralization assays. The results showed that for groups injected with virions only and groups injected with the mixture of virions and antiserum against VP124, the crayfish mortalities were 100% and 60% on the 8th day postinfection, individually. The virus infection could be delayed or neutralized by antibody against the envelope protein VP124. Quantitative PCR was used to further investigate the influence of three antisera described above on the virus infection. The results showed that the antiserum against VP124 could restrain the propagation of WSSV in crayfish. All of the results suggested that the viral envelope protein VP124 played a role in WSSV infection.

Universal COVID-19 Vaccine Targeting SARS-CoV-2 Envelope Protein

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), had caused over 382 million cases and over 2.7 million deaths globally as of 23 March 2021. By that date, at least 10 SARS-CoV-2 variants had emerged. The transmissibility and lethality of the variants are higher than those of the Wuhan reference strain. Therefore, a universal vaccine for the reference strain and all variants (present and future) is indispensable. The coronavirus envelope (E) protein is an integral membrane protein crucial to the viral lifecycle and the pathogenesis of coronaviruses. The SARS-CoV-2 E protein has a postsynaptic density protein 95/Drosophila disc large tumor suppressor/zonula occludens-1 (PDZ) binding motif (PBM), and its interaction with PDZ-domain-2 of the human tight junction protein may interrupt the integrity of lung epithelium. Furthermore, the SARS-CoV-2 E protein itself is a homopentameric cation channel viroporin, which may be involved in viral release. This protein is thus a potential target for the development of a universal COVID-19 vaccine, because of its highly conserved amino acid sequence. The variant mutations occur mainly in the spike protein, and conservation of E protein remained in most Variants of Concern (VOC). Only one of the extant VOC have mutations in the E protein that P71L mutation occurs in the South African variant 501Y.V2 (B.1.351). If a vaccine is designed to target E protein, two scenarios are possible: 1) SARS-CoV-2 maintains a highly conserved E protein amino acid sequence, rendering the virus consistently or permanently susceptible to the vaccine;or 2) the E protein mutates and new variants evolve accordingly. In scenario 2, the tertiary structure and function of the E protein homopentameric cation channel viroporin, PBM, or other aspects affecting pathogenicity would be attenuated. Either scenario would thus ameliorate the pandemic. I therefore propose that a vaccine targeting the SARS-CoV-2 E protein would be effective against the Wuhan reference strain and all current and future SARS-CoV-2 variants. Efforts to create E protein-based vaccines are ongoing. Further research and clinical trials are needed to realize this universal COVID-19 vaccine.

The recombinant truncated envelope protein of West Nile virus adjuvanted with Alum/CpG induces potent humoral and T cell immunity in mice

West Nile virus(WNV)is a mosquito-transmitted flavivirus distributed globally for decades and can cause disease in humans and animals.So far,no WNV vaccine has been licensed for human use.Therefore,the development of novel candidate vaccines and the improvement of vaccination strategies is imperative.As the WNV envelope(E)glycoprotein plays an important role in mediating viral binding to cellular receptors and virus-cell membrane fusion,it is a critical target for the host humoral response.Here,we prepared a recombinant truncated envelope protein of WNV(rWNV-80E)and developed a WNV subunit vaccine formulation with a combination of aluminum hydroxide(alum)and a synthetic oligonucleotide CpG as adjuvants.C57BL/6 mice were immunized twice intramuscularly at 28-day intervals with 5μg purified rWNV-80E adjuvanted with Alum/CpG.WNV E-specific IgG was detected by enzyme-linked immunosorbent assay and neutralizing antibodies(nAbs)was detected using single-round infectious particles of WNV.Furthermore,T cell immunity was detected by enzyme-linked immunospot assay and intracellular cytokine staining assay.Notably,rWNV-80E was highly immunogenic and elicited potent humoral and cell immunity,as evidenced by significant levels of IFN-γ and TNF-αsecretion in the T cells of mice.In summary,the Alum/CpG-adjuvanted rWNV-80E subunit vaccine elicited potent and balanced B-and T-cell immunity in mice,and therefore it is a promising candidate vaccine that warrants further investigation for use in human or veterinary applications.

Baculovirus Surface Display of Zika Virus Envelope Protein Protects against Virus Challenge in Mouse Model

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-a/b and IFN-c receptor deficient)mice immunized with recombinant E protein were protected against lethal ZIKV challenge.Together,thesefindings 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.

ATP1B3 Restricts Hepatitis B Virus Replication Via Reducing the Expression of the Envelope Proteins

Our recent study reported that ATP1B3 inhibits hepatitis B virus(HBV)replication via inducing NF-κB activation.However,ATP1B3 mutants which were defective in NF-κB activation still maintained the moderate degree of suppression on HBV replication,suggesting that another uncharacterized mechanism is also responsible for ATP1B3-mediated HBV suppression.Here,we demonstrated that ATP1B3 reduced the expression of HBV envelope proteins LHBs,MHBs and SHBs,but had no effect on intracellular HBV DNA,RNA levels as well as HBV promoter activities.Further investigation showed that proteasome inhibitor MG132 rescued ATP1B3-mediated envelope proteins degradation,demonstrating that proteasome-dependent pathway is involved in ATP1B3-induced degradation of envelope proteins.Co-IP showed that ATP1B3 interacts with LHBs and MHBs and induces LHBs and MHBs polyubiquitination.Immunofluorescence colocalization analysis confirmed LHBs and MHBs colocalized with ATP1B3 together.Our work provides important information for targeting ATP1B3 as a potential therapeutic molecule for HBV infection.

E Protein Prokaryotic Expression of Avian Infectious Bronchitis Virus

The small envelope protein （E） gene of avian infectious bronchitis virus （IBV） M41 strain was cloned, and then it was subcloned into prokaryotic expressing vector pGEX-6P-1. The recombinant plasmid was transformed into E.coli. BL21 and induced by IPTG. SDS-PAGE result showed that when objective protein fused with GST （about 20 ku）, the relative molecular mass of fusion protein was 38 ku. It indicated that objective protein was about 12.4 ku. The result showed that E protein was expressed successfully, it was useful to the subsequent E protein research.

A single nonsynonymous mutation on ZIKV E protein-coding sequences leads to markedly increased neurovirulence in vivo

Zika virus(ZIKV)can infect a wide range of tissues including the developmental brain of human fetus.Whether specific viral genetic variants are linked to neuropathology is incompletely understood.To address this,we have intracranially serially passaged a clinical ZIKV isolate(SW01)in neonatal mice and discovered variants that exhibit markedly increased virulence and neurotropism.Deep sequencing analysis combining with molecular virology studies revealed that a single 67D(Aspartic acid)to N(Asparagine)substitution on E protein is sufficient to confer the increased virulence and neurotropism in vivo.Notably,virus clones with D67N mutation had higher viral production and caused more severe cytopathic effect(CPE)in human neural astrocytes U251 cells in vitro,indicating its potential neurological toxicity to human brain.These findings revealed that a single mutation D67N on ZIKV envelope may lead to severe neuro lesion that may help to explain the neurovirulence of ZIKV and suggest monitoring the occurrence of this mutation during nature infection may be important.

Genetically engineered bacterial-like particles induced specific cellular and humoral immunity as effective tick-borne encephalitis virus vaccine

Tick-borne encephalitis(TBE)is a natural focal disease with fatal encephalitis induced by tick-borne encephalitis virus(TBEV),seriously threatening human and public health.Protection of TBE depends on vaccination with inactivated vaccine,which requires high cost and multiple immunizations.Here,we construct genetically engineered bacterial-like particles(BLPs)as an effective TBEV vaccine with simplified immunizations and improved immune efficacy.The TBEV BLPs involve the combination of the gram-positive enhancer matrix from Lactococcus lactis,and TBEV envelope(E)protein expressed by genetically engineered recombinant baculovirus.The prepared TBEV BLPs can effectively stimulate the activation of dendritic cells to present the TBEV E proteins to T and B cells,leading to strong and durable cellular and humoral immune responses in mice.Surprisingly,the serum levels of specific IgG antibodies in mice remain about 10^(6)at 6 months after the secondary immunization.Overall,the TBEV BLPs can be used as a potent vaccine candidate,laying the foundation for developing novel TBEV genetically engineered vaccines.

Rearrangement of Actin Cytoskeleton by Zika Virus Infection Facilitates Blood–Testis Barrier Hyperpermeability

In recent years,various serious diseases caused by Zika virus(ZIKV)have made it impossible to be ignored.Confirmed existence of ZIKV in semen and sexually transmission of ZIKV suggested that it can break the blood–testis barrier(BTB),or Sertoli cell barrier(SCB).However,little is known about the underlying mechanism.In this study,interaction between actin,an important component of the SCB,and ZIKV envelope(E)protein domainⅢ(EDⅢ)was inferred from coimmunoprecipitation(Co-IP)liquid chromatography–tandem mass spectrometry(LC–MS/MS)analysis.Confocal microscopy confirmed the role of actin filaments(F-actin)in ZIKV infection,during which part of the stress fibers,the bundles that constituted by paralleled actin filaments,were disrupted and presented in the cell periphery.Colocalization of E and reorganized actin filaments in the cell periphery of transfected Sertoli cells suggests a participation of ZIKV E protein in ZIKV-induced F-actin rearrangement.Perturbation of F-actin by cytochalasin D(CytoD)or Jasplakinolide(Jas)enhanced the infection of ZIKV.More importantly,the transepithelial electrical resistance(TEER)of an in vitro mouse SCB(mSCB)model declined with the progression of ZIKV infection or overexpression of E protein.Co-IP and confocal microscopy analyses revealed that the interaction between F-actin and tight junction protein ZO-1 was reduced after ZIKV infection or E protein overexpression,highlighting the role of E protein in ZIKV-induced disruption of the BTB.We conclude that the interaction between ZIKV E and F-actin leads to the reorganization of F-actin network,thereby compromising BTB integrity.

Anti-lipopolysaccharide factor D from kuruma shrimp exhibits antiviral activity

Anti-lipopolysaccharide factors(ALFs)exhibit a potent antimicrobial activity against a broad range of bacteria,filamentous fungi,and viruses.In previous reports,seven groups of ALFs(groups A–G)were identified in penaeid shrimp.Among them,group D showed negative net charges and weak antimicrobial activity.Whether this group has antiviral function is not clear.In this study,the ALF sequences of penaeid shrimp were analyzed,and eight groups of ALF family(groups A–H)were identified.The four ALFs including MjALF-C2,MjALF-D1,MjALF-D2,and MjALF-E2 from kuruma shrimp Marsupenaeus japonicus were expressed recombinantly in Escherichia coli,and the antiviral activity was screened via injection of purified recombinant ALFs into shrimp following white spot syndrome virus(WSSV)infection.Results showed that the expression of Vp28(WSSV envelope protein)decreased significantly in the MjALF-D2-injected shrimp only.Therefore,MjALF-D2 was chosen for further study.Expression pattern analysis showed that MjAlf-D2 was upregulated in shrimp challenged by WSSV.The WSSV replication was detected in RNA,genomic DNA,and protein levels using VP28 and Ie1(immediate-early gene of WSSV)as indicators in MjALF-D2-injected shrimp following WSSV infection.Results showed that WSSV replication was significantly inhibited compared with that in the rTRX-or PBS-injected control groups.After knockdown of MjAlf-D2 in shrimp by RNA interference,the WSSV replication increased significantly in the shrimp.All these results suggested that MjALF-D2 has an antiviral function in shrimp immunity,and the recombinant ALF-D2 has a potential application for viral disease control in shrimp aquaculture.

HIV-1B gp120 genes from one patient with AIDS dementia complex can affect the secretion of tumor necrosis factor and interleukin lp in glial cells

Background HIV-1 infected and immune-activated macrophages and microglia secrete neurotoxins, such as tumor necrosis factor-a （TNF-a） and interleukin-113 （IL-113）, which play major role in the neuronal death. It has been shown that different HIV-1 variants have varying abilities to elicit secretion of TNF-a by peripheral blood mononuclear cell （PBMC）; however, whether the difference of gp120 gene could affect the secretion of TNF-a and IL-113 by glial cells is unknown. The aim of this study was to explore the association between gene diversity and induction of neurotoxic cytokines. Methods In this study, we constructed retroviral vectors MSCV-IRES-GFP/gp120 using HIV-1 gp120 genes isolated from four different tissues of one patient who died of AIDS dementia complex （ADC）. Recombinant retroviruses produced by cotransfection of MSCV-IRES-GFP/gp120, pCMV-VSV-G and pUMVC into 293T cells were collected and added into U87 glial cells. Concentrations of TNF-α and IL-1β secreted by transduced U87 cells were assayed with ELISA separately. Results The four HIV-1 gp120 were in the different branch of the neighbor-joining tree. Compared to the pMIG retrovirus （gp120-negative） or U87 cells, all the gp120-positive recombinant retroviruses induced more TNF-a （P 〈0.01） and IL-113 （P 〈0.01）. In addition, compared with the L/MIG retrovirus, all the three brain gp120-positive recombinant retroviruses induced less TNF-α （P 〈0.01） and IL-1β （P 〈0.01）. Conclusions HIV-1 gp120 could induce U87 cells secret more TNF-α and IL-1β again. The more important is that difference of HIV-1 gp120, especially cell-tropism may account for the different ability in eliciting secretion of TNF-α and IL-1 β, which might supply a novel idea helping understand the pathogenesis of ADC.