HIV-1 gp120 V3区的结构特征及其生物学功能

研究表明HIV-1包膜蛋白gp120上的V3环在病毒结合到靶细胞的过程中起着重要的作用。这个区域中的几个氨基酸残基与gp120同辅受体的结合相关联,在HIV-1感染过程的早期,V3环在患者体内诱导针对HIV病毒的抗体应答,并被确定为主要中和决定簇。一些针对V3环的抗体具有广泛的中和活性,但是,V3环是HIV包膜蛋白的一个高变区,发生着广泛的变异,综述了V3环的结构特征和变异以及生物学功能,并对V3环的免疫反应进行了探讨。

Antiviral Activity of Dual-acting Hydrocarbon-stapled Peptides against HIV-1 Predominantly Circulating in China

Objective New rationally designed i,i＋7-hydrocarbon-stapled peptides that target both HIV-1 assembly and entry have been shown to have antiviral activity against HIV-1 subtypes circulating in Europe and North America. Here, we aimed to evaluate the antiviral activity of these peptides against HIV-1 subtypes predominantly circulating in China. Methods The antiviral activity of three i,i＋7-hydrocarbon-stapled peptides, NYAD-36, NYAD-67, and NYAD-66, against primary HIV-1 CRF07_BC and CRFOI_AE isolates was evaluated in peripheral blood mononuclear cells （PI3MCs）. The activity against the CRF07_BC and CRF01_AE Env-pseudotyped viruses was analyzed in TZM-bl cells. Results We found that all the stapled peptides were effective in inhibiting infection by all the primary HIV-1 isolates tested, with 50% inhibitory concentration toward viral replication （ICso） in the low micromolar range. NYAD-36 and NYAD-67 showed better antiviral activity than NYAD-66 did. We further evaluated the sensitivity of CRF01_AE and CRF07_BC Env-pseudotyped viruses to these stapled peptides in a single-cycle virus infectivity assay. As observed with the primary isolates, the ICs0s were in the low micromolar range, and NYAD-66 was less effective than NYAD-36 and NYAD-67. Conclusion Hydrocarbon-stapled peptides appear to have broad antiviral activity against the predominant HIV-1 viruses in China. This finding may provide the impetus to the rational design of peptides for future antiviral therapy.

Advances in the research and development of therapeutic antibodies against the Zika virus

The Zika virus(ZIKV)is an arbovirus in the same family,Flaviviridae,as the dengue virus(DENV),the West Nile virus,the yellow fever virus,and the Japanese encephalitis virus.ZIKV has been a recent research focus because of its close association with severe human diseases and syndromes,particularly congenital Zika syndrome,which includes fetal microcephaly and other brain abnormalities.1 The ZIKV envelope(E)protein is a major structural protein involved in receptor binding,viral entry,and fusion.It is arranged as a dimer,with each monomer consisting of three domains(DI,DII,and DIII),a stem region,and a transmembrane region.2 The ZIKV E protein induces the production of potent neutralizing antibodies against ZIKV and is thus a key target for the development of therapeutic ZIKV antibodies.

RETRACTED ARTICLE:SARS-CoV-2 infects T lymphocytes through its spike protein-mediated membrane fusion

The authors have retracted this article [1]. After the publication ofthis article, it came to the authors attention that in order tosupport the conclusions of the study, the authors should haveused primary T cells instead of T cell lines. Additionally, there areconcerns that the flow cytometry methodology applied here wasflawed. These points resulted in the conclusions being consideredinvalid.

处于临床研究阶段可预防人免疫缺陷病毒性传播的杀微生物剂

艾滋病（acquired immunodeficiency syndrome，AIDS）是由人免疫缺陷病毒（human immunodeficiency virus，HIV）感染引起的一类传染性疾病，目前全球仍有近4000万例感染者，是威胁人类健康的第一大单一病因疾病。由于艾滋病疫苗的问世尚需时日，要想彻底遏制HIV的传播，必须找到一种新的高效、价廉的途径。而杀微生物剂（microbicides）就是这样一条被国际社会寄予厚望的HIV预防途径。

鉴定HIV-1包膜蛋白gp41的近膜端外部区与其N端三聚体结构域之间的相互作用:病毒融合相关的潜在机制

人类Ⅰ型免疫缺陷病毒(human immunodeficiency class I, HIV-1)包膜蛋白gp41的近膜端外部区(membrane proximal external region, MPER)在HIV-1的各个分化株之间相当保守,这暗示MPER区对于病毒的生存和侵染均具有十分重要的作用.目前研究表明,两个靶向HIV-1且具有最广泛中和活性的单抗2F5和4E10,都特异地识别该区域,进而有效地抑制包膜蛋白介导的病毒膜融合过程.我们先前的研究表明,4E10抗体表位的抗原性和免疫原性会随着gp41融合核心区域的结构调整而发生显著的改变,提示在gp41蛋白的MPER区与融合核心区之间很有可能存在某种联系,并与gp41介导的膜融合过程相关.本研究利用各种不同的gp41融合核心区衍生多肽,检测了4E10表位多肽(D4E10P)与它们之间的反应性.其中,具有gp41蛋白核心区N-trimer结构的多肽(N-trimer-6HB)显示出很强的结合活性.进一步对N-trimer-6HB多肽进行噬菌体文库筛选,发现4E10表位上一个短的模体序列(WF)很有可能对gp41的N-trimer和MPER区之间的相互作用发挥了至关重要的作用,导致MPER区以潜在的方式参与病毒包膜和靶细胞膜间的融合过程.

Characterization of the receptor-binding domain(RBD)of 2019 novel coronavirus:implication for development of RBD protein as a viral attachment inhibitor and vaccine

The outbreak of Coronavirus Disease 2019(COVID-19)has posed a serious threat to global public health,calling for the development of safe and effective prophylactics and therapeutics against infection of its causative agent,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),also known as 2019 novel coronavirus(2019-nCoV).The CoV spike(S)protein plays the most important roles in viral attachment,fusion and entry,and serves as a target for development of antibodies,entry inhibitors and vaccines.Here,we identified the receptor-binding domain(RBD)in SARS-CoV-2 S protein and found that the RBD protein bound strongly to human and bat angiotensin-converting enzyme 2(ACE2)receptors.SARS-CoV-2 RBD exhibited significantly higher binding affinity to ACE2 receptor than SARS-CoV RBD and could block the binding and,hence,attachment of SARS-CoV-2 RBD and SARS-CoV RBD to ACE2-expressing cells,thus inhibiting their infection to host cells.SARS-CoV RBD-specific antibodies could crossreact with SARS-CoV-2 RBD protein,and SARS-CoV RBD-induced antisera could cross-neutralize SARS-CoV-2,suggesting the potential to develop SARS-CoV RBD-based vaccines for prevention of SARS-CoV-2 and SARS-CoV infection.

The First Disease X is Caused by a Highly Transmissible Acute Respiratory Syndrome Coronavirus

Based on the announcement of the World Health Organization(WHO) in 2018, the Wuhan pneumonia caused by an unknown etiology should be recognized as the first Disease X. Later, the pathogen was identified to be a novel coronavirus denoted 2019-nCoV, which has 79.5% and 96% whole genome sequence identify to SARS-CoV and bat SARS-related coronavirus(SARSr-CoV-RaTG13), respectively, suggesting its potential bat origin. With high human-to-human transmission rate(R0), 2019-nCoV has quickly spread in China and other countries, resulting in 34,953 confirmed cases and 725 deaths as of 8 February 2020, thus calling for urgent development of therapeutics and prophylactics. Here we suggest renaming 2019-nCoV as "transmissible acute respiratory syndrome coronavirus(TARS-CoV)" and briefly review the advancement of research and development of neutralizing antibodies and vaccines targeting the receptor-binding domain(RBD) and viral fusion inhibitors targeting the heptad repeat 1(HR1) domain in spike protein of 2019-nCoV.

Fusion mechanism of 2019-nCoV and fusion inhibitors targeting HR1 domain in spike protein

Very recently,a novel coronavirus,2019-nCoV,emerged in Wuhan,China and then quickly spread worldwide,resulting in>17,388 confirmed cases and 361 deaths as of 3 February 2020,thus calling for the development of safe and effective therapeutics and prophylatics.1,2 Similar to severe acute respiratory syndrome(SARS)-CoV,2019-nCoV belongs to lineage B betacoronavirus,and it has the ability to utilize human angiotensin-converting enzyme 2(ACE2)as a receptor to infect human cells.

Identification of an ideal adjuvant for receptor-binding domain-based subunit vaccines against Middle East respiratory syndrome coronavirus

Middle East respiratory syndrome （MERS）, an emerging infectious disease caused by MERS coronavirus （MERS-CoV）, has garnered worldwide attention as a consequence of its continuous spread and pandemic potential, making the development of effective vaccines a high priority. We previously demonstrated that residues 377-588 of MERS-CoV spike （S） protein receptor-binding domain （RBD） is a very promising MERS subunit vaccine candidate, capable of inducing potent neutralization antibody responses. In this study, we sought to identify an adjuvant that optimally enhanced the immunogenicity of S377-588 protein fused with Fc of human IgG （S377-588-Fc）. Specifically, we compared several commercially available adjuvants, including Freund＇s adjuvant, aluminum, Monophosphoryl lipid A, Montanide ISA51 and MF59 with regard to their capacity to enhance the immunogenicity of this subunit vaccine. In the absence of adjuvant, S377-588-Fc alone induced readily detectable neutralizing antibody and T-cell responses in immunized mice. However, incorporating an adjuvant improved its immunogenicity. Particularly, among the aforementioned adjuvants evaluated, MF59 is the most potent as judged by its superior ability to induce the highest titers of IgG, IgG1 and IgG2a subtypes, and neutralizing antibodies. The addition of MF59 significantly augmented the immunogenicity of S377-588-Fcto induce strong IgG and neutralizing antibody responses as well as protection against MERS-CoV infection in mice, suggesting that MF59 is an optimal adjuvant for MERS-CoV RBD-based subunit vaccines.

Roles of the hemagglutinin of influenza A virus in viral entry and development of antiviral therapeutics and vaccines

Seasonal influenza epidemics and influenza pandemics caused by influenza A virus(IAV)has resulted in millions of deaths in the world.The development of anti-IAV vaccines and therapeutics is urgently needed for prevention and treatment of IAV infection and for controlling future influenza pandemics.Hemagglutinin(HA)of IAV plays a critical role in viral binding,fusion and entry,and contains the major neutralizing epitopes.Therefore,HA is an attractive target for developing anti-IAV drugs and vaccines.Here we have reviewed the recent progress in study of conformational changes of HA during viral fusion process and development of HA-based antiviral therapeutics and vaccines.

Development of oncolytic virotherapy:from genetic modification to combination therapy

Oncolytic virotherapy(OVT)is a novel form of immunotherapy using natural or genetically modified viruses to selectively replicate in and kill malignant cells.Many genetically modified oncolytic viruses(OVs)with enhanced tumor targeting,antitumor efficacy,and safety have been generated,and some of which have been assessed in clinical trials.Combining OVT with other immunotherapies can remarkably enhance the antitumor efficacy.In this work,we review the use of wild-type viruses in OVT and the strategies for OV genetic modification.We also review and discuss the combinations of OVT with other immunotherapies.

Cross-neutralization of SARS coronavirus-specific antibodies against bat SARS-like coronaviruses

Dear Editor,The 2002–2003 global pandemic caused by severe acute respiratory syndrome coronavirus(SARS-CoV)infected around 8,000 people with 10%mortality(http://www.who.int/csr/sars/en/).The virus has a positivestranded RNA genome that encodes a large polyprotein(1a and 1ab),four structural proteins,including spike(S),

Retraction Note to:SARS-CoV-2 infects T lymphocytes through its spike protein-mediated membrane fusion

The authors have retracted this article1.After the publication of this article,it came to the authors attention that in order to support the conclusions of the study,the authors should have used primary T cells instead of T-cell lines.In addition,there are concerns that the flow cytometry methodology applied here was flawed.These points resulted in the conclusions being considered invalid.

Development of small-molecule viral inhibitors targeting various stages of the life cycle of emerging and re-emerging viruses

In recent years, unexpected outbreaks of infectious diseases caused by emerging and re-emerging viruses have become more frequent, which is possibly due to environmental changes. These outbreaks result in the loss of life and economic hardship. Vaccines and therapeutics should be developed for the prevention and treatment of infectious diseases. In this review, we summarize and discuss the latest progress in the development of small-molecule viral inhibitors against highly pathogenic coronaviruses, including severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronavirus, Ebola virus, and Zika virus. These viruses can interfere with the specific steps of viral life cycle by blocking the binding between virus and host cells, disrupting viral endocytosis, disturbing membrane fusion, and interrupting viral RNA replication and translation, thereby demonstrating potent therapeutic effect against various emerging and re-emerging viruses. We also discuss some general strategies for developing small-molecule viral inhibitors.

Neutralizing antibodies for the prevention and treatment of COVID-19

Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)initiates the infection process by binding to the viral cellular receptor angiotensin-converting enzyme 2 through the receptor-binding domain(RBD)in the S1 subunit of the viral spike(S)protein.This event is followed by virus–cell membrane fusion mediated by the S2 subunit,which allows virus entry into the host cell.Therefore,the SARS-CoV-2 S protein is a key therapeutic target,and prevention and treatment of coronavirus disease 2019(COVID-19)have focused on the development of neutralizing monoclonal antibodies(nAbs)that target this protein.In this review,we summarize the nAbs targeting SARS-CoV-2 proteins that have been developed to date,with a focus on the N-terminal domain and RBD of the S protein.We also describe the roles that binding affinity,neutralizing activity,and protection provided by these nAbs play in the prevention and treatment of COVID-19 and discuss the potential to improve nAb efficiency against multiple SARSCoV-2 variants.This review provides important information for the development of effective nAbs with broad-spectrum activity against current and future SARS-CoV-2 strains.

The development of HIV vaccines targeting gp41 membrane-proximal external region （MPER）： challenges and prospects

A human immunodeficiency virus type-1 （HIV-1） vaccine which is able to effectively prevent infection would be the most powerful method of extinguishing pandemic of the acquired immunodeficiency syndrome （AIDS）. Yet, achieving such vaccine remains great challenges. The membrane-proximal external region （MPER） is a highly conserved region of the envelope glycoprotein （Env） gp41 subunit near the viral envelope surface, and it plays a key role in membrane fusion. It is also the target of some reported broadly neutralizing antibodies （bNAbs）. Thus, MPER is deemed to be one of the most attractive vaccine targets. However, no one can induce these bNAbs by immunization with immunogens con- taining the MPER sequence（s）. The few attempts at developing a vaccine have only resulted in the induction of neutralizing antibodies with quite low potency and limited breadth. Thus far, vaccine failure can be attrib- uted to various characteristics of MPER, such as those involving structure and immunology; therefore, we will focus on these and review the recent progress in the field from the following perspectives： （1） MPER structure and its role in membrane fusion, （2） the epitopes and neutralization mechanisms of MPER-specific bNAbs, as well as the limitations in eliciting neutralizing antibodies, and （3） different strategies for MPER vaccine design and current harvests.

The interaction between the membrane-proximal external region and the N-trimer region of HIV-1 gp41: Involvement in viral fusion

The membrane proximal external region (MPER) of gp41 is extremely conserved among diverse HIV-1 variants, implying its important role in viral infection. Interestingly, two of the most broadly neutralizing antibodies, 2F5 and 4E10, specifically recognize this region. Our previous study demonstrated that the antigenicity and immunogenicity of 4E10 epitope are affected by remodeling gp41 fusion core, suggesting that the MPER may be associated with gp41 core and involved in gp41-mediated membrane fusion. Here we measured the binding activity of 4E10 epitope peptide (D4E10P) with various gp41 core-derived peptides and found that the N-trimer region in a construct designated N-trimer-6HB interacted significantly with D4E10P. Using N-trimer-6HB to screen a phage library, we identified a motif (WF) located in 4E10 epitope that may play a certain role in the interaction of gp41 MPER with the N-trimer in gp41 fusion core and, we thus speculated upon the potential involvement of MPER in the fusion process between viral envelope and target cell membrane.

Directed shift of vaginal flora after topical application of sucrose gel in a phase Ⅲ clinical trial： a novel treatment for bacterial vaginosis

Background Bacterial vaginosis （BV） is one of the most common infectious diseases among sexually active women and is associated with the increased acquisition of a variety of sexually transmitted diseases.This study aimed to compare the efficacy of a non-antibiotic sucrose gel against an antibiotic metronidazole gel for the treatment of BV.Methods A randomized, double-blinded, multi-center, parallel-group, placebo-controlled phase Ⅲ clinical trial was conducted at eight hospitals in China.A total of 560 subjects with clinically diagnosed BV were randomly assigned into three groups for vaginally receiving sucrose, metronidazole, and placebo gels, respectively, twice daily for five consecutive days.The efficacy of therapeutic cure, defined as an achievement of both microbiologic cure （a Nugent score of 3 or less） and clinical cure （a resolution of the clinical findings from the baseline visit）, was evaluated at the 1st and 2nd test-of-cure （TOC） visits at 7-10 and 21-35 days after the start of treatment, respectively.Results Therapeutic cure rates for sucrose, metronidazole, and placebo gel groups were 83.13%, 71.30% and 0.92%,at the 1st TOC, and 61.04%, 66.67% and 7.34%, at the 2nd TOC, respectively.While there was no significant difference between the sucrose and metronidazole gel groups at the 2nd TOC （P=0.305）, and sucrose gel was more effective than metronidazole gel at the 1st TOC （P=0.009）.Conclusion These findings suggest that sucrose gel restores normal vaginal flora more rapidly than metronidazole gel and can be used as a novel treatment for BV.

SARS-CoV-2 spike protein: a key target for eliciting persistent neutralizing antibodies

A recent paper published in Science describes the detection of IgG antibody responses in individuals infected by severe acute respiratory syndrome coronavirus(SARS-CoV-2).The authors also examined the duration of antibody production and the correlation between IgG antibody titers and neutralizing antibody titers.1 This study provides information about the kinetics of antibody production,and the functionality and longevity of these antibodies,in patients with Coronavirus Disease 2019(COVID-19).The SARS-CoV-2 genome encodes spike(S),nucleocapsid,membrane,and envelope structural proteins.The S protein plays a key role in viral infection and pathogenesis.