[CT texture analysis for predicting pseudoprogression in metastatic clear cell renal cell carcinoma during PD-1 inhibitor therapy]

Objective: To evaluate the effectiveness of enhanced CT texture feature analysis in predicting pseudoprogression in patients with metastatic clear cell renal cell carcinoma (mccRCC) undergoing programmed cell death protein 1 (PD-1) inhibitor therapy. Methods: A cross-sectional study. Data from 32 patients with mccRCC were retrospectively collected who received monotherapy with PD-1 inhibitors after standard treatment failure at Henan Cancer Hospital, from June 2015 to January 2021. Clinical information and enhanced CT images were analyzed to assess target lesion response. The lesions were divided into pseudoprogression and non-pseudoprogression groups. Manual segmentation of target lesions was performed using ITK-Snap software on baseline enhanced CT, and texture analysis was conducted using A.K. software to extract feature parameters. Differences in texture features between the pseudoprogression and non-pseudoprogression groups were analyzed using univariate and multivariate logistic regression. A predictive model for pseudoprogression was constructed, and its performance was evaluated using ROC curve analysis. Results: A total of 32 patients with 89 lesions were included in the study. Statistical analysis revealed significant differences in seven texture features between the pseudoprogression and non-pseudoprogression groups. These features included"original_ngtdm_Strength"(0.49 vs. -0.61,P=0.006), "wavelet-HLH_glszm_ZonePercentage"(0.67 vs. -0.22,P=0.024),"wavelet-LHL_ngtdm_Strength"(1.20 vs. -0.51,P=0.002), "wavelet-HLL_gldm_LargeDependenceEmphasis"(-0.84 vs. 0.19,P=0.002), "wavelet-HLH_glcm_Id" (-0.30 vs. 0.43,P=0.037),"wavelet- HLH_glrlm_RunPercentage"(0.45 vs. -0.01,P=0.032),"wavelet-LHH_firstorder_Skewness"(0.25 vs. -0.27, P=0.011). Based on these features, a pseudoprogression prediction model was developed with a P-value of 0.000 2 and an odds ratio of 0.045 (95%CI 0.009-0.227). The model exhibited a high predictive performance with an AUC of 0.907 (95%CI 0.817-0.997) according to ROC curve analysis. Conclusions: Enhanced CT texture feature analysis shows promise in predicting lesion pseudoprogression in patients with metastatic ccRCC undergoing PD-1 inhibitor therapy. The developed predictive model based on texture features demonstrates good performance and may assist in evaluating treatment response in these patients.

Epidemiology characteristics of human coronaviruses in patients with respiratory infection symptoms and phylogenetic analysis of HCoV-OC43 during 2010-2015 in Guangzhou

Human coronavirus (HCoV) is one of the most common causes of respiratory tract infection throughout the world. To investigate the epidemiological and genetic variation of HCoV in Guangzhou, south China, we collected totally 13048 throat and nasal swab specimens from adults and children with fever and acute upper respiratory infection symptoms in Gunazhou, south China between July 2010 and June 2015, and the epidemiological features of HCoV and its species were studied. Specimens were screened for HCoV by real-time RT-PCR, and 7 other common respiratory viruses were tested simultaneously by PCR or real-time PCR. HCoV was detected in 294 cases (2.25%) of the 13048 samples, with most of them inpatients (251 cases, 85.4% of HCoV positive cases) and young children not in nursery (53.06%, 156 out of 294 HCoV positive cases). Four HCoVs, as OC43, 229E, NL63 and HKU1 were detected prevalent during 2010–2015 in Guangzhou, and among the HCoV positive cases, 60.20% were OC43, 16.67% were 229E, 14.97% were NL63 and 7.82% were HKU1. The month distribution showed that totally HCoV was prevalent in winter, but differences existed in different species. The 5 year distribution of HCoV showed a peak-valley distribution trend, with the detection rate higher in 2011 and 2013 whereas lower in 2010, 2012 and 2014. The age distribution revealed that children (especially those <3 years old) and old people (>50 years) were both high risk groups to be infected by HCoV. Of the 294 HCoV positive patients, 34.69% (101 cases) were co-infected by other common respiratory viruses, and influenza virus was the most common co-infecting virus (30/101, 29.70%). Fifteen HCoV-OC43 positive samples of 2013–2014 were selected for S gene sequencing and phylogenetic analysis, and the results showed that the 15 strains could be divided into 2 clusters in the phylogenetic tree, 12 strains of which formed a separate cluster that was closer to genotype G found in Malaysia. It was revealed for the first time that genotype B and genotype G of HCoV-OC43 co-circulated and the newly defined genotype G was epidemic as a dominant genotype during 2013–2014 in Guanzhou, south China.

[Modification factors associated with maternally inherited non-syndromic hearing loss]

Mutations in the mitochondrial DNA have been certified to be one of the most important causes of maternally inherited sensorineural hearing loss. Among these, mitochondrial 12S rRNA1555A>G, 1494C>T and other mutations are associated with both nonsyndromic and drug induced hearing loss caused by aminoglycosides. Individuals carrying 1555A>G or 1494C>T mutation have a variety of clinical manifestations, which implies that the 1555A>G or 1494C>T mutation is a chief factor underlying the development of deafness but insufficient to produce the clinical phenotype. Therefore other modifier factors, such as aminoglycosides, mitochondrial haplotypes, secondary mutation or nuclear modifier genes, may play an important role in the phenotypic expression of the deafness-associated mitochondrial 12S rRNA1555A>G or 1494C>T mutation. In this review, the modifier factors for the phenotypic expression of deafness-associated mitochondrial 12S rRNA1555A>G or 1494C>T mutations were summarized and proposed the pathogenesis of maternally inherited deafness.

PAN substitutions A37S, A37S/I61T and A37S/V63I attenuate the replication of H7N7 influenza A virus by impairing the polymerase and endonuclease activities

Substitutions in the PA N-terminus (PAN) of influenza A viruses are associated with viral pathogenicity. During our previous study, which identified PAN-V63I and -A37S/I61T/V63I/V100A substitutions as virulence determinants, we observed a severe decrease in virus growth and transcription/replication capacity posed by PAN-A37S/V100A substitution. To further delineate the significance of substitutions at these positions, we generated mutant H7N7 viruses bearing the substitutions PAN-A37S, -A37S/I61T, -A37S/V63I, -V100A, -I61T/V100A and -V63I/V100A by reverse genetics. Our results showed that all mutant viruses except PAN-V100A showed a significantly reduced growth capability in infected cells. At the same time, the PAN-A37S, -A37S/I61T and -A37S/V63I mutant viruses displayed decreased viral transcription and replication by diminishing virus RNA synthesis activity. Biochemical assays indicated that the substitutions PAN-A37S, -A37S/I61T and -A37S/V63I suppressed the polymerase and endonuclease activities when compared with those of the wild-type. Together, our results demonstrated that the PAN-A37S, -A37S/I61T and -A37S/V63I substitutions contributed to a decreased pathogenicity of avian H7N7 influenza A virus.

Antibody-Dependent Cell-Mediated Cytotoxicity Epitopes on the Hemagglutinin Head Region of Pandemic H1N1 Influenza Virus Play Detrimental Roles in H1N1-Infected Mice

Engaging the antibody-dependent cell-mediated cytotoxicity (ADCC) for killing of virus-infected cells and secretion of antiviral cytokines and chemokines was incorporated as one of the important features in the design of universal influenza vaccines. However, investigation of the ADCC epitopes on the highly immunogenic influenza hemagglutinin (HA) head region has been rarely reported. In this study, we determined the ADCC and antiviral activities of two putative ADCC epitopes, designated E1 and E2, on the HA head of a pandemic H1N1 influenza virus in vitro and in a lethal mouse model. Our data demonstrated that sera from the E1-vaccinated mice could induce high ADCC activities. Importantly, the induction of ADCC response modestly decreased viral load in the lungs of H1N1-infected mice. However, the elevated ADCC significantly increased mouse alveolar damage and mortality than that of the PBS-vaccinated group (P < 0.0001). The phenotype was potentially due to an exaggerated inflammatory cell infiltration triggered by ADCC, as an upregulated release of cytotoxic granules (perforin) was observed in the lung tissue of E1-vaccinated mice after H1N1 influenza virus challenge. Overall, our data suggested that ADCC elicited by certain domains of HA head region might have a detrimental rather than protective effect during influenza virus infection. Thus, future design of universal influenza vaccine shall strike a balance between the induction of protective immunity and potential side effects of ADCC.

[Mutation analysis of GJB2 gene in 1 822 patients with nonsyndromic hearing loss in Zhejiang Province]

Objective:To analyze the genetic characteristics in nonsyndromic hearing impairment (NSHL) patients in Zhejiang province.Method:Peripheral blood samples were obtained from 1822 NSHL patients and 467 normal hearing controls in Zhejiang province. We carried out a systematic mutational screening of GJB2 gene in these subjects by amplifying the coding region of GJB2 gene and sequencing directly.Result:Thirty kinds of mutation were identified, including eleven pathogenic mutations, one hypomorphic allele, sixteen polymorphic mutations and two novel mutations. The c.235delC mutation was the most prevalent pathogenic mutation in this cohort (18.50%), and the rate of allele mutation was 12.16%. The frequency of c.299_300delAT,c.176_191del16,c.512_513insAACG,c.35delG,c.283G>A,c.427C>T,c.35insG,c.439G>A,c.571T>C,c.139G>T mutations were decreased in turn.Conclusion:c.235delC mutation is the hot spot of GJB2 gene mutation in NSHL patients in Zhejiang province and the most common mutational pattern is frame-shift mutation. The discovery of novel mutations enriches the spectrum and frequency of variants in GJB2 gene.

PB2 substitutions V598T/I increase the virulence of H7N9 influenza A virus in mammals

PB2 is one of the subunits of the influenza A virus (IAV) polymerase complex. By bioinformatics analysis we identified PB2 substitutions at positions 389 and 598 among IAV isolates from humans, which might associate with viral pathogenicity. To evaluate the biological significance of these substitutions, PB2-K389R and -V598T/I mutant viruses of avian H7N9 IAVs were generated by reverse genetics. Compared to the wild type, the mutant viruses displayed an enhanced growth capacity in human and mammalian cells. Meanwhile, they presented increased transcription and replication by producing higher levels of viral mRNA, cRNA and vRNA. Minireplicon assays indicated that the polymerase activity was elevated by these substitutions. Notably, the PB2-V598T/I substitutions substantially increased virus replication and virulence in mice. Together, we demonstrated that the substitutions PB2-V598T/I contributed to higher IAV replication and virulence in mammals, which added to the knowledge of IAV virulence determinants and benefited the surveillance of IAVs.

Identification and genomic characterization of a novel rat bocavirus from brown rats in China

Despite recent discoveries of novel animal bocaparvoviruses, current understandings on the diversity and evolution of bocaparvoviruses are still limited. We report the identification and genome characterization of a novel bocaparvovirus, rat bocaparvovirus (RBoV), in brown rats (Rattus norvegicus) in China. RBoV was detected in 11.5%, 2.4%, 16.2% and 0.3% of alimentary, respiratory, spleen and kidney samples respectively, of 636 brown rats by PCR, but not in samples of other rodent species, suggesting that brown rats are the primary reservoir of RBoV. Six RBoV genomes sequenced from three brown rats revealed the presence of three ORFs, characteristic of bocaparvoviruses. Phylogenetic analysis showed that RBoV was distantly related to other bocaparvoviruses, forming a distinct cluster within the genus, with ≤55.5% nucleotide identities to the genome of ungulate bocaparvovirus 3, supporting its classification as a novel bocaparvovirus species. RBoV possessed a putative second exon encoding the C-terminal region of NS1 and conserved RNA splicing signals, similar to human bocaparvoviruses and canine bocaparvovirus. In contrast to human, feline and canine bocaparvoviruses which demonstrates inter/intra-host viral diversity, partial VP1/VP2 sequences of 49 RBoV strains demonstrated little inter-host genetic diversity, suggesting a single genetic group. Although the pathogenicity of RBoV remains to be determined, its presence in different host tissues suggests wide tissue tropism. RBoV represents the first bocaparvovirus in rodents with genome sequenced, which extends our knowledge on the host range of bocaparvoviruses. Further studies are required to better understand the epidemiology, genetic diversity and pathogenicity of bocaparvoviruses in different rodent populations.

Identification of a novel small-molecule compound targeting the influenza A virus polymerase PB1-PB2 interface

The PB1 C-terminal domain and PB2 N-terminal domain interaction of the influenza A polymerase, which modulates the assembly of PB1 and PB2 subunits, may serve as a valuable target for the development of novel anti-influenza therapeutics. In this study, we performed a systematic screening of a chemical library, followed by the antiviral evaluation of primary hits and their analogues. Eventually, a novel small-molecule compound PP7 that abrogated the PB1-PB2 association and impaired viral polymerase activity was identified. PP7 exhibited antiviral activities against influenza virus subtypes A (H1N1)pdm09, A(H7N9) and A(H9N2) in cell cultures and partially protected mice against lethal challenge of mouse-adapted influenza A (H1N1)pdm09 virus. Surprisingly, a panel of other subtypes of influenza virus, including A(H5N1) and A(H7N7), showed various degrees of resistance to the compound. Biochemical studies revealed a similar pattern of resistance on the impairment of polymerase activity. Molecular docking analyses suggested a PP7-binding site that appeared to be completely conserved among the subtypes of the virus mentioned above. Thus, we propose that alternative/additional binding site (s) may exist for the regulation of PB1-PB2 subunits assembly of influenza A virus.

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A novel small-molecule compound was identified to provide anti-influenza effect in vitro and in vivo.

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An RT-qPCR based assay was modified to evaluate the polymerase activity of various subtypes of influenza viruses.

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The PB1-PB2 assembly strategies of the trimeric polymerase complex might be stain/subtype specific.

Identification and interspecies transmission of a novel bocaparvovirus among different bat species in China

We report the discovery of a novel bocaparvovirus, bat bocaparvovirus (BtBoV), in one spleen, four respiratory and 61 alimentary samples from bats of six different species belonging to three families, Hipposideridae, Rhinolophidae and Vespertilionidae. BtBoV showed a higher detection rate in alimentary samples of Rhinolophus sinicus (5.7 %) than those of other bat species (0.43-1.59 %), supporting R. sinicus as the primary reservoir and virus spillover to accidental bat species. BtBoV peaked during the lactating season of R. sinicus, and it was more frequently detected among female than male adult bats (P<0.05), and among lactating than non-lactating female bats (P<0.0001). Positive BtBoV detection was associated with lower body weight in lactating bats (P<0.05). Ten nearly complete BtBoV genomes from three bat species revealed a unique large ORF1 spanning NS1 and NP1 in eight genomes and conserved splicing signals leading to multiple proteins, as well as a unique substitution in the conserved replication initiator motif within NS1. BtBoV was phylogenetically distantly related to known bocaparvoviruses with ≤57.3 % genome identities, supporting BtBoV as a novel species. Ms-BtBoV from Miniopterus schreibersii and Hp-BtBoV from Hipposideros pomona demonstrated 97.2-99.9 % genome identities with Rs-BtBoVs from R. sinicus, supporting infection of different bat species by a single BtBoV species. Rs-BtBoV_str15 represents the first bat parvovirus genome with non-coding regions sequenced, which suggested the presence of head-to-tail genomic concatamers or episomal forms of the genome. This study represents the first to describe interspecies transmission in BoVs. The high detection rates in lactating female and juvenile bats suggest possible vertical transmission of BtBoV.

Novel Mutations L228I and Y232H Cause Nonnucleoside Reverse Transcriptase Inhibitor Resistance in Combinational Pattern

The emergence of drug resistance mutations is increasing after the implementation of highly active antiretroviral therapy. To characterize two novel mutations L228I and Y232H in the primer grip of reverse transcriptase (RT) of HIV-1 circulating recombination form 08_BC (CRF08_BC) subtype, both mutant clones were constructed to determine their impacts on viral phenotypic susceptibility and replication capacity (RC). Results showed that the novel mutation, L228I, conferred a low-level resistance to etravirine by itself. L228I in combination with Y188C displayed a high level of cross-resistance to both nevirapine (NVP) and efavirenz (EFV). The copresence of A139V and Y232H induced a moderate level of resistance to NVP and EFV. Mutations Y188C/L228I, A139V, Y232H, and A139V/Y232H reduced more than 55% of viral RC compared with that of the wild-type (WT) reference virus. Modeling study suggested that the copresence of Y188C/L228I or A139V/Y232H might induce conformational changes to RT, which might result in reduced drug susceptibility and viral RC due to abolished hydrogen bonding or complex interaction with vicinal residues. Our results demonstrated that L228I and Y232H were novel accessory nonnucleoside reverse transcriptase inhibitor resistance-related mutations and provided valuable information for clinicians to design more effective treatment to patients infected with HIV-1 subtype CRF08_BC.

Novel residues in the PA protein of avian influenza H7N7 virus affect virulence in mammalian hosts

To evaluate the pathogenicity, a highly pathogenic avian influenza H7N7 virus (A/Netherlands/219/03) isolated from human was passaged in mice. A mutant virus (mH7N7) with attenuated virulence was isolated from mouse lung, which had a 3-log higher MLD50 than the wild-type virus (wH7N7). Sequence analysis and reverse genetics study revealed that mutations in PA account for the compromised viral replication in mammalian cells and mice. A mini-genome assay demonstrated that PA mutations P103H and S659L can cooperatively decrease polymerase activity. Actually, PA with double mutation P103H-S659L cannot sustain the generation of live virus by reverse genetics. Interestingly, the prior infection of mH7N7 virus provided mice with cross-protection against lethal challenge of other subtypes of influenza A virus including H1N1, H5N1 and H7N9. In conclusion, we demonstrated that PA mutations P103H and S659L can cooperatively reduce polymerase activity and viral replication in mammalian cells and attenuate pathogenicity in mice.

Peptide-Mediated Interference of PB2-eIF4G1 Interaction Inhibits Influenza A Viruses' Replication in Vitro and in Vivo

Influenza viruses are obligate parasites that hijack the host cellular system. Previous results have shown that the influenza virus PB2 subunit confers a dependence of host eukaryotic translation initiation factor 4-γ 1 (eIF4G1) for viral mRNA translation. Here, we demonstrated that peptide-mediated interference of the PB2-eIF4G1 interaction inhibited virus replication in vitro and in vivo. Remarkably, intranasal administration of the peptide provided 100% protection against lethal challenges of influenza A viruses in BALB/c mice, including H1N1, H5N1, and H7N9 influenza virus subtypes. Mapping of the PB2 protein indicated that the eIF4G1 binding sites resided within the PB2 cap-binding domain. Virtual docking analysis suggested that the inhibitory peptide associated with the conserved amino acid residues that were essential to PB2 cap-binding activity. Overall, our results identified the PB2-eIF4G1 interactive site as a druggable target for influenza therapeutics.

[Spectrum of GJB6 variants in 318 pedigrees with non-syndromic hearing loss:one deafness pedigree carrying both GJB6 and GJB2 deletion variant]

Objective:To investigate the mutation characteristics of GJB6 (gap juction bata 6) gene in 318 Han Chinese pedigrees with non-syndromic hearing loss.Method:Polymerase chain reaction was used to detect the coding region of GJB6 gene in 318 Han Chinese pedigrees with non-syndromic hearing loss.Gene arrays and second generation sequencing were used to detect 118 genes which had reported to be accosiated with deafness in members of pedigree which possibly carried pathogenic GJB6 gene mutation.Result:Here,we have screened the mutations of GJB6 gene in 318 Han Chinese pedigrees with non-syndromic hearing loss and found one pedigree carrying both GJB6 and GJB2 gene deletion.Clinical and molecular genetic evaluation revealed the variable phenotype of hearing impairments including age-at-onset,audiometric configuration and severity in these subjects.Mutational analysis of the GJB2 and GJB6 gene coding region showed a heterozygous 235 del C of GJB2 gene and a novel 228 del G of GJB6 gene.Conclusion:GJB6 gene 228 del G variant,which occurs at a highly evolutionarily conserved nucleotide,forward the stop codon to 81 position and result in the corresponding polypeptide 181 amino acids shorter than wildtype polypeptide.In addition,GJB6 gene 228 del G absent varies among 94 unrelated Chinese controls.Our finding suggest that GJB6 gene 228 del G maybe a novel pathogenic mutation associated with non-syndromic hearing loss.

A novel small-molecule compound disrupts influenza A virus PB2 cap-binding and inhibits viral replication

OBJECTIVES

The conserved residues 318-483 in the PB2 subunit of influenza A polymerase is an independently folded cap-binding domain (PB2cap) that exhibits a distinct binding mode from other host cap-binding proteins, which suggests that PB2cap might be an ideal drug target. This study aimed to identify a new class of anti-influenza inhibitors that specifically disrupts the interaction between PB2cap and host cap structures.

METHODS

An innovative fluorescence polarization assay was established for primary screening, followed by cap-binding inhibitory activity, antiviral efficacy and cytotoxicity evaluations of the selected compounds. The best compound was characterized by multi-cycle virus growth assay, cross-protection test, synergism evaluation, mini-replicon assay, binding affinity analysis, docking simulation and mouse study.

RESULTS

Several PB2 cap-binding inhibitors were discovered. The compound 7-(4-hydroxy-2-oxo-2H-chromen-3-yl)-6H,7H,8H-chromeno[3',4':5,6]pyrano[3,2-c]chromene-6,8-dione, designated PB2-39, was identified as a potent inhibitor of replication of multiple subtypes of influenza A virus, including H1N1, H3N2, H5N1, H7N7, H7N9 and H9N2 in vitro and H1N1, H5N1 and H7N9 in vivo. Combinational treatment with the influenza virus release inhibitor zanamivir and PB2-39 exerted a synergistic anti-influenza effect. Mechanistic experiments supported that PB2-39 suppressed viral polymerase activity. Docking and binding affinity analyses demonstrated that PB2-39 interacted with the PB2 cap-binding pocket, suggesting its role as a cap-binding competitor.

CONCLUSIONS

Our study provides new insights for the strategic development of novel cap-binding inhibitors of influenza A viruses.

[Dose optimization of lipid infusionin treatment of patients with acute dexmedetomidinepoisoning]

OBJECTIVE

To optimize the dose of lipid infusion in treatment of patients with acute dexmedetomidinepoisoning, in order to further guide the rational use of medication in clinical practice.

METHODS

A total of 80 patients with acute dexmedetomidinepoisoning were admitted in this study from January 2012 to October 2014 at our hospital and divided into three groups based on the intensity of poisoning, including: slight poisoning (28 cases), moderate poisoning (32 cases) and severe poisoning (20 cases). Patients in each group were given 10% lipid infusion or 20% lipid infusion for treatment.Stable blood dexmedetomidineconcentrations of patients in pre-treatment and at different time points after treatment (pre-treatment and 0.5, 1, 2, 5, 10, 20 h after treatment) and the length of hospital stay, awake time in each group were investigated and compared.Ramsay sedation scores were recorded and compared in different time points (0.5 h before treatment and 2, 5, 20 h after treatment) in each group for different treatments.Side effects and complications were recorded, and follow-up was conducted during 1-3 d post discharge to record the recovery condition in patients.

RESULTS

In each group, patients receiving 20% lipid infusion waked earlier than those receiving 10% lipid infusion.And the hospitalization duration for patients receiving 20% lipid infusion was significantly shorter than those receiving 10% lipid infusion [(4.6±1.6) h vs (6.7±2.0) h, (2.6±0.4) d vs (4.0±0.6) d, P<0.05]. The Ramsay sedation scores were significantly lower for patients receiving 20% lipid infusion than those receiving 10% lipid infusionat 2 h and 5 h after treatment in each group [(3.4±0.3) vs (4.7±0.4), (2.6±0.3) h vs (3.5±0.3) h, P<0.05]. The stable plasma concentrations of dexmedetomidine were gradually reduced after the treatment, and which were lower when compared with the theoretical metabolic concentration.What's more, the plasma concentrationsat 1 h, 2 h and 5 h after treatment were significantly lower for patientsreceiving 20% lipid infusion than those receiving 10% lipid infusion in each group (P>0.05). All patients in our study were cured and discharged without severe side effects and complications, and follow-ups showed that no patients showed evidence of rebound phenomenon.

CONCLUSIONS

Different concentrations of lipid infusionare safe and effective in relieving the intensity of dexmedetomidinepoisoning, and promoting the clinical recovery.What's more, the therapeutic efficacy of 20% lipid infusion is greater than 10% lipid infusion.

A novel small-molecule inhibitor of influenza A virus acts by suppressing PA endonuclease activity of the viral polymerase

The RNA-dependent RNA polymerase of influenza A virus comprises conserved and independently-folded subdomains with defined functionalities. The N-terminal domain of the PA subunit (PA_N) harbors the endonuclease function so that it can serve as a desired target for drug discovery. To identify a class of anti-influenza inhibitors that impedes PA_N endonuclease activity, a screening approach that integrated the fluorescence resonance energy transfer based endonuclease inhibitory assay with the DNA gel-based endonuclease inhibitory assay was conducted, followed by the evaluation of antiviral efficacies and potential cytotoxicity of the primary hits in vitro and in vivo. A small-molecule compound ANA-0 was identified as a potent inhibitor against the replication of multiple subtypes of influenza A virus, including H1N1, H3N2, H5N1, H7N7, H7N9 and H9N2, in cell cultures. Combinational treatment of zanamivir and ANA-0 exerted synergistic anti-influenza effect in vitro. Intranasal administration of ANA-0 protected mice from lethal challenge and reduced lung viral loads in H1N1 virus infected BALB/c mice. In summary, ANA-0 shows potential to be developed to novel anti-influenza agents.

A novel peptide with potent and broad-spectrum antiviral activities against multiple respiratory viruses

A safe, potent and broad-spectrum antiviral is urgently needed to combat emerging respiratory viruses. In light of the broad antiviral activity of β-defensins, we tested the antiviral activity of 11 peptides derived from mouse β-defensin-4 and found that a short peptide, P9, exhibited potent and broad-spectrum antiviral effects against multiple respiratory viruses in vitro and in vivo, including influenza A virus H1N1, H3N2, H5N1, H7N7, H7N9, SARS-CoV and MERS-CoV. The antiviral activity of P9 was attributed to its high-affinity binding to viral glycoproteins, as well as the abundance of basic amino acids in its composition. After binding viral particles through viral surface glycoproteins, P9 entered into cells together with the viruses via endocytosis and prevented endosomal acidification, which blocked membrane fusion and subsequent viral RNA release. This study has paved the avenue for developing new prophylactic and therapeutic agents with broad-spectrum antiviral activities.

Combined prokaryotic-eukaryotic delivery and expression of therapeutic factors through a primed autocatalytic positive-feedback loop

Progress in bacterial therapy for cancer and infectious diseases is hampered by the absence of safe and efficient vectors. Sustained delivery and high gene expression levels are critical for the therapeutic efficacy. Here we developed a Salmonella typhimrium strain to maintain and safely deliver a plasmid vector to target tissues. This vector is designed to allow dual transcription of therapeutic factors, such as cytotoxic proteins, short hairpin RNAs or combinations, in the nucleus or cytoplasm of eukaryotic cells, with this expression sustained by an autocatalytic positive-feedback loop. Mechanisms to prime the system and maintain the plasmid in the bacterium are also provided. Synergistic effects of attenuated Salmonella and our inter-kingdom system allow the precise expression of Diphtheria toxin A chain (DTA) gene in tumor microenvironment and eradicate large established tumors in immunocompetent animals. In the experiments reported here, 26% of mice (n=5/19) with aggressive tumors were cured and the others all survived until the end of the experiment. We also demonstrated that ST4 packaged with shRNA-encoding plasmids has sustained knockdown effects in nude mice bearing human MDA-MB-231 xenografts. Three weeks after injection of 5×10(6) ST4/pIKT-shPlk, PLK1 transcript levels in tumors were 62.5±18.6% lower than the vector control group (P=0.015). The presence of PLK1 5' RACE-PCR cleavage products confirmed a sustained RNAi-mediated mechanism of action. This innovative technology provides an effective and versatile vehicle for efficient inter-kingdom gene delivery that can be applied to cancer therapy and other purposes.

IL-17A Promotes Pulmonary B-1a Cell Differentiation via Induction of Blimp-1 Expression during Influenza Virus Infection

B-1 cells play a critical role in early protection during influenza infections by producing natural IgM antibodies. However, the underlying mechanisms involved in regulating this process are largely unknown. Here we found that during influenza infection pleural cavity B-1a cells rapidly infiltrated lungs, where they underwent plasmacytic differentiation with enhanced IgM production. This process was promoted by IL-17A signaling via induction of Blimp-1 expression and NF-κB activation in B-1a cells. Deficiency of IL-17A led to severely impaired B-1a-derived antibody production in the respiratory tract, resulting in a deficiency in viral clearance. Transfer of B-1a-derived natural antibodies rescued Il17a^-/- mice from otherwise lethal infections. Together, we identify a critical function of IL-17A in promoting the plasmacytic differentiation of B-1a cells. Our findings provide new insights into the mechanisms underlying the regulation of pulmonary B-1a cell response against influenza infection.

Influenza infection is highly localized in respiratory tract where immune response is triggered to provide protection from primary infection. Although natural IgM antibodies produced by B-1a cells have long been recognized as first-line protection against influenza, it remains unclear whether B-1a cell response occurs in the lung and what molecular mechanisms regulate this process. We show that airway exposure to influenza causes migration of B-1a cells to lungs for further differentiation into plasma cells with enhanced production of protective IgM antibodies. IL-17A critically regulates this process by driving differentiation of B-1a cells to high-rate IgM producing plasma cells in situ. Thus, IL-17A is a key factor in the local inflammatory milieu that modulates early humoral immunity afforded by B-1a cells.

Middle East Respiratory Syndrome Coronavirus Efficiently Infects Human Primary T Lymphocytes and Activates the Extrinsic and Intrinsic Apoptosis Pathways

Middle East respiratory syndrome (MERS) is associated with a mortality rate of >35%. We previously showed that MERS coronavirus (MERS-CoV) could infect human macrophages and dendritic cells and induce cytokine dysregulation. Here, we further investigated the interplay between human primary T cells and MERS-CoV in disease pathogenesis. Importantly, our results suggested that MERS-CoV efficiently infected T cells from the peripheral blood and from human lymphoid organs, including the spleen and the tonsil. We further demonstrated that MERS-CoV infection induced apoptosis in T cells, which involved the activation of both the extrinsic and intrinsic apoptosis pathways. Remarkably, immunostaining of spleen sections from MERS-CoV–infected common marmosets demonstrated the presence of viral nucleoprotein in their CD3⁺ T cells. Overall, our results suggested that the unusual capacity of MERS-CoV to infect T cells and induce apoptosis might partly contribute to the high pathogenicity of the virus.

ANXA3/JNK Signaling Promotes Self-Renewal and Tumor Growth, and Its Blockade Provides a Therapeutic Target for Hepatocellular Carcinoma

Frequent tumor relapse in hepatocellular carcinoma (HCC) has been commonly attributed to the presence of residual cancer stem cells (CSCs) after conventional treatments. We have previously identified and characterized CD133 to mark a specific CSC subset in HCC. In the present study, we found endogenous and secretory annexin A3 (ANXA3) to play pivotal roles in promoting cancer and stem cell-like features in CD133+ liver CSCs through a dysregulated JNK pathway. Blockade of ANXA3 with an anti-ANXA3 monoclonal antibody in vitro as well as in human HCC xenograft models resulted in a significant reduction in tumor growth and self-renewal. Clinically, ANXA3 expression in HCC patient sera closely associated with aggressive clinical features. Our results suggest that ANXA3 can serve as a novel diagnostic biomarker and that the inhibition of ANXA3 may be a viable therapeutic option for the treatment of CD133+ liver-CSC-driven HCC.

Identification of TMPRSS2 as a Susceptibility Gene for Severe 2009 Pandemic A(H1N1) Influenza and A(H7N9) Influenza

The genetic predisposition to severe A(H1N1)2009 (A[H1N1]pdm09) influenza was evaluated in 409 patients, including 162 cases with severe infection and 247 controls with mild infection. We prioritized candidate variants based on the result of a pilot genome-wide association study and a lung expression quantitative trait locus data set. The GG genotype of rs2070788, a higher-expression variant of TMPRSS2, was a risk variant (odds ratio, 2.11; 95% confidence interval, 1.18-3.77; P = .01) to severe A(H1N1)pdm09 influenza. A potentially functional single-nucleotide polymorphism, rs383510, accommodated in a putative regulatory region was identified to tag rs2070788. Luciferase assay results showed the putative regulatory region was a functional element, in which rs383510 regulated TMPRSS2 expression in a genotype-specific manner. Notably, rs2070788 and rs383510 were significantly associated with the susceptibility to A(H7N9) influenza in 102 patients with A(H7N9) influenza and 106 healthy controls. Therefore, we demonstrate that genetic variants with higher TMPRSS2 expression confer higher risk to severe A(H1N1)pdm09 influenza. The same variants also increase susceptibility to human A(H7N9) influenza.

An H5N1-based matrix protein 2 ectodomain tetrameric peptide vaccine provides cross-protection against lethal infection with H7N9 influenza virus

In March 2013, a patient infected with a novel avian influenza A H7N9 virus was reported in China. Since then, there have been 458 confirmed infection cases and 177 deaths. The virus contains several human-adapted markers, indicating that H7N9 has pandemic potential. The outbreak of this new influenza virus highlighted the need for the development of universal influenza vaccines. Previously, we demonstrated that a tetrameric peptide vaccine based on the matrix protein 2 ectodomain (M2e) of the H5N1 virus (H5N1-M2e) could protect mice from lethal infection with different clades of H5N1 and 2009 pandemic H1N1 influenza viruses. In this study, we investigated the cross-protection of H5N1-M2e against lethal infection with the new H7N9 virus. Although five amino acid differences existed at positions 13, 14, 18, 20, and 21 between M2e of H5N1 and H7N9, H5N1-M2e vaccination with either Freund's adjuvant or the Sigma adjuvant system (SAS) induced a high level of anti-M2e antibody, which cross-reacted with H7N9-M2e peptide. A mouse-adapted H7N9 strain, A/Anhui/01/2013m, was used for lethal challenge in animal experiments. H5N1-M2e vaccination provided potent cross-protection against lethal challenge of the H7N9 virus. Reduced viral replication and histopathological damage of mouse lungs were also observed in the vaccinated mice. Our results suggest that the tetrameric H5N1-M2e peptide vaccine could protect against different subtypes of influenza virus infections. Therefore, this vaccine may be an ideal candidate for developing a universal vaccine to prevent the reemergence of avian influenza A H7N9 virus and the emergence of potential novel reassortants of influenza virus.

In vitro selection of HIV-1 CRF08_BC variants resistant to reverse transcriptase inhibitors

Human immunodeficiency virus type 1 (HIV-1) circulating recombinant form 08_BC (CRF08_BC), carrying the recombinant reverse transcriptase (RT) gene from subtypes B and C, has recently become highly prevalent in Southern China. As the number of patients increases, it is important to characterize the drug resistance mutations of CRF08_BC, especially against widely used antiretrovirals. In this study, clinically isolated virus (2007CNGX-HK), confirmed to be CRF08_BC with its sequence deposited in GenBank (KF312642), was propagated in human peripheral blood mononuclear cells (PBMCs) with increasing concentrations of nevirapine (NVP), efavirenz (EFV), or lamivudine (3TC). Three different resistance patterns led by initial mutations of Y181C, E138G, and Y188C were detected after the selection with NVP. Initial mutations, in combination with other previously reported substitutions (K20R, D67N, V90I, K101R/E, V106I/A, V108I, F116L, E138R, A139V, V189I, G190A, D218E, E203K, H221Y, F227L, N348I, and T369I) or novel mutations (V8I, S134N, C162Y, L228I, Y232H, E396G, and D404N), developed during NVP selection. EFV-associated variations contained two initial mutations (L100I and Y188C) and three other mutations (V106L, F116Y, and A139V). Phenotypic analyses showed that E138R, Y181C, and G190A contributed high-level resistance to NVP, while L100I and V106L significantly reduced virus susceptibility to EFV. Y188C was 20-fold less sensitive to both NVP and EFV. As expected, M184I alone, or with V90I or D67N, decreased 3TC susceptibility by over 1,000-fold. Although the mutation profile obtained in culture may be different from the patients, these results may still provide useful information to monitor and optimize the antiretroviral regimens.

A novel mutation, D404N, in the connection subdomain of reverse transcriptase of HIV-1 CRF08_BC subtype confers cross-resistance to NNRTIs

OBJECTIVES

Growing evidence suggests that mutations in the connection domain of the HIV-1 reverse transcriptase (RT) can contribute to viral resistance to RT inhibitors. This work was designed to determine the effects of a novel mutation, D404N, in the connection subdomain of RT of HIV-1 CRF08_BC subtype on drug resistance, viral replication capacity (RC) and RT activity.

METHODS

Mutation D404N, alone or together with the other reported mutations, was introduced into an HIV-1 CRF08_BC subtype infectious clone by site-directed mutagenesis. Viral susceptibility to nine RT inhibitors, viral RC and the DNA polymerase activity of viral RT of the constructed virus mutants were investigated. A modelling study using the server SWISS-MODEL was conducted to explore the possible structure-related drug resistance mechanism of the mutation D404N.

RESULTS

Single mutations D404N and H221Y conferred low-level resistance to nevirapine, efavirenz, rilpivirine and zidovudine. Double mutations Y181C/D404N and Y181C/H221Y significantly reduced susceptibility to NNRTIs. The most pronounced resistance to NNRTIs was observed with the triple mutation Y181C/D404N/H221Y. Virus containing D404N as the only mutation displayed ∼50% RC compared with the WT virus. The modelling study suggested that the D404N mutation might abolish the hydrogen bonds between residues 404 and K30 in p51 or K431 in p66, leading to impaired RT subunit structure and enhanced drug resistance.

CONCLUSIONS

These results indicate that D404N is a novel NNRTI-associated mutation in the HIV-1 subtype CRF08_BC and provides information valuable for the monitoring of clinical RTI resistance.

Advancements in the development of subunit influenza vaccines

The ongoing threat of influenza epidemics and pandemics has emphasized the importance of developing safe and effective vaccines against infections from divergent influenza viruses. In this review, we first introduce the structure and life cycle of influenza A viruses, describing major influenza A virus-caused pandemics. We then compare different types of influenza vaccines and discuss current advancements in the development of subunit influenza vaccines, particularly those based on nucleoprotein (NP), extracellular domain of matrix protein 2 (M2e) and hemagglutinin (HA) proteins. We also illustrate potential strategies for improving the efficacy of subunit influenza vaccines.

Complex structure of MERS-CoV spike glycoprotein with human receptor DPP4

Recently identified the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) causes severe and fatal acute respiratory illness in human. No prophylactic and therapeutic agents specifically against MERS-CoV are currently available. Entry of MERS-CoV into the target cells depends on binding of receptor-binding domain (RBD) on viral envelope spike glycoprotein to the cellular receptor dipeptidyl peptidase 4 (DPP4). We report the 3.0 angstrom-resolution crystal structure of MERS-CoV RBD bound to the extracellular domain of DPP4. The structure shows that MERS-CoV RBD consists of a core and a receptor binding subdomain. MERS-CoV RBD and related SARS-CoV RBD share a high degree of structural similarity in their core subdomains, but are notably divergent in the receptor binding subdomain. Structural and mutagenesis analyses identified several key residues in the receptor binding subdomain of RBD that are critical for viral binding to DPP4 and entry into the target cell. Two RBD-specific potent human neutralizing monoclonal antibodies were derived from single-chain variable region fragments (scFvs) of nonimmune human antibody library. They inhibited infection of both pseudotyped and live MERS-CoV with IC50 at nanomolar concentration. Biochemical analysis indicated that these two antibodies blocked RBD interaction with DPP4 on the cell surface.

Transmission of avian influenza A(H7N9) virus from father to child: a report of limited person-to-person transmission, Guangzhou, China, January 2014

We investigated a possible person-to-person transmission within a family cluster of two confirmed influenza A(H7N9) patients in Guangzhou, China. The index case, a man in his late twenties, worked in a wet market that was confirmed to be contaminated by the influenza A(H7N9) virus. He developed a consistent fever and severe pneumonia after 4 January 2014. In contrast, the second case, his five-year-old child, who only developed a mild disease 10 days after disease onset of the index case, did not have any contact with poultry and birds but had unprotected and very close contact with the index case. The sequences of the haemagglutinin (HA) genes of the virus stains isolated from the two cases were 100% identical. These findings strongly suggest that the second case might have acquired the infection via transmission of the virus from the sick father. Fortunately, all 40 close contacts, including the other four family members who also had unprotected and very close contact with the cases, did not acquire influenza A(H7N9) virus infection, indicating that the person-to-person transmissibility of the virus remained limited. Our finding underlines the importance of carefully, thoroughly and punctually following-up close contacts of influenza A(H7N9) cases to allow detection of any secondary cases, as these may constitute an early warning signal of the virus's increasing ability to transmit from person-to-person.

Potent neutralization of MERS-CoV by human neutralizing monoclonal antibodies to the viral spike glycoprotein

The recently identified Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe and fatal acute respiratory illness in humans. However, no prophylactic and therapeutic agents specifically against MERS-CoV are currently available. Entry of MERS-CoV into target cells depends on binding of the receptor binding domain (RBD) of the viral envelope spike glycoprotein to the cellular receptor dipeptidyl peptidase 4 (DPP4). We report the isolation and characterization of two potent human RBD-specific neutralizing monoclonal antibodies (MERS-4 and MERS-27) derived from single-chain variable region fragments of a nonimmune human antibody library. MERS-4 and MERS-27 inhibited infection of both pseudotyped and live MERS-CoV with IC50 (half-maximal inhibitory concentration) at nanomolar concentrations. MERS-4 also showed inhibitory activity against syncytia formation mediated by interaction between MERS-CoV spike glycoprotein and DPP4. Combination of MERS-4 and MERS-27 demonstrated a synergistic effect in neutralization against pseudotyped MERS-CoV. Biochemical analysis indicated that MERS-4 and MERS-27 blocked RBD interaction with DPP4 on the cell surface. MERS-4, in particular, bound soluble RBD with an about 45-fold higher affinity than DPP4. Mutagenesis analysis suggested that MERS-4 and MERS-27 recognized distinct regions in RBD. These results suggest that MERS-4 and MERS-27 are RBD-specific potent inhibitors and could serve as promising candidates for prophylactic and therapeutic interventions against MERS-CoV infection.

A novel neutralizing antibody against diverse clades of H5N1 influenza virus and its mutants capable of airborne transmission

Highly pathogenic avian influenza A virus H5N1 continues to spread among poultry and has frequently broken the species barrier to humans. Recent studies have shown that a laboratory-mutated or reassortant H5N1 virus bearing hemagglutinin (HA) with as few as four or five mutations was capable of transmitting more efficiently via respiratory droplets between ferrets, posing a serious threat to public health and underscoring the priority of effective vaccines and therapeutics. In this study, we identified a novel monoclonal antibody (mAb) named HAb21, that has a broadly neutralizing activity against all tested strains of H5N1 covering clades 0, 1, 2.2, 2.3.4, and 2.3.2.1. Importantly, HAb21 efficiently neutralized diverse H5N1 variants with single or combination forms of mutations capable of airborne transmission. We demonstrated that HAb21 blocked viral entry during the receptor-binding step by targeting a previously uncharacterized epitope at the tip of the HA head. This novel epitope closely neighbors the receptor-binding site (RBS) and the interface of HA trimer and is highly conserved among divergent H5N1 strains. Our studies provide a new tool for use either for therapeutic purposes or as a basis of vaccine development.

Productive replication of Middle East respiratory syndrome coronavirus in monocyte-derived dendritic cells modulates innate immune response

The Middle East respiratory syndrome coronavirus (MERS-CoV) closely resembled severe acute respiratory syndrome coronavirus (SARS-CoV) in disease manifestation as rapidly progressive acute pneumonia with multi-organ dysfunction. Using monocyte-derived-dendritic cells (Mo-DCs), we discovered fundamental discrepancies in the outcome of MERS-CoV- and SARS-CoV-infection. First, MERS-CoV productively infected Mo-DCs while SARS-CoV-infection was abortive. Second, MERS-CoV induced significantly higher levels of IFN-γ, IP-10, IL-12, and RANTES expression than SARS-CoV. Third, MERS-CoV-infection induced higher surface expression of MHC class II (HLA-DR) and the co-stimulatory molecule CD86 than SARS-CoV-infection. Overall, our data suggests that the dendritic cell can serve as an important target of viral replication and a vehicle for dissemination. MERS-CoV-infection in DCs results in the production of a rich combination of cytokines and chemokines, and modulates innate immune response differently from that of SARS-CoV-infection. Our findings may help to explain the apparent discrepancy in the pathogenicity between MERS-CoV and SARS-CoV.

Broad-spectrum antivirals for the emerging Middle East respiratory syndrome coronavirus

OBJECTIVES

Middle East respiratory syndrome coronavirus (MERS-CoV) has emerged to cause fatal infections in patients in the Middle East and traveler-associated secondary cases in Europe and Africa. Person-to-person transmission is evident in outbreaks involving household and hospital contacts. Effective antivirals are urgently needed.

METHODS

We used small compound-based forward chemical genetics to screen a chemical library of 1280 known drugs against influenza A virus in Biosafety Level-2 laboratory. We then assessed the anti-MERS-CoV activities of the identified compounds and of interferons, nelfinavir, and lopinavir because of their reported anti-coronavirus activities in terms of cytopathic effect inhibition, viral yield reduction, and plaque reduction assays in Biosafety Level-3 laboratory.

RESULTS

Ten compounds were identified as primary hits in high-throughput screening. Only mycophenolic acid exhibited low EC50 and high selectivity index. Additionally, ribavirin and interferons also exhibited in-vitro anti-MERS-CoV activity. The serum concentrations achievable at therapeutic doses of mycophenolic acid and interferon-β1b were 60-300 and 3-4 times higher than the concentrations at which in-vitro anti-MERS-CoV activities were demonstrated, whereas that of ribavirin was ∼2 times lower. Combination of mycophenolic acid and interferon-β1b lowered the EC50 of each drug by 1-3 times.

CONCLUSIONS

Interferon-β1b with mycophenolic acid should be considered in treatment trials of MERS.

Active replication of Middle East respiratory syndrome coronavirus and aberrant induction of inflammatory cytokines and chemokines in human macrophages: implications for pathogenesis

Middle East respiratory syndrome coronavirus (MERS-CoV) infection caused severe pneumonia and multiorgan dysfunction and had a higher crude fatality rate (around 50% vs 10%) than SARS coronavirus (SARS-CoV) infection. To understand the pathogenesis, we studied viral replication, cytokine/chemokine response, and antigen presentation in MERS-CoV–infected human monocyte–derived macrophages (MDMs) versus SARS-CoV–infected MDMs. Only MERS-CoV can replicate in MDMs. Both viruses were unable to significantly stimulate the expression of antiviral cytokines (interferon α [IFN-α] and IFN-β) but induced comparable levels of tumor necrosis factor α and interleukin 6. Notably, MERS-CoV induced significantly higher expression levels of interleukin 12, IFN-γ, and chemokines (IP-10/CXCL-10, MCP-1/CCL-2, MIP-1α/CCL-3, RANTES/CCL-5, and interleukin 8) than SARS-CoV. The expression of major histocompatibility complex class I and costimulatory molecules were significantly higher in MERS-CoV–infected MDMs than in SARS-CoV–infected cells. MERS-CoV replication was validated by immunostaining of infected MDMs and ex vivo lung tissue. We conclusively showed that MERS-CoV can establish a productive infection in human macrophages. The aberrant induction of inflammatory cytokines/chemokines could be important in the disease pathogenesis.

A safe and convenient pseudovirus-based inhibition assay to detect neutralizing antibodies and screen for viral entry inhibitors against the novel human coronavirus MERS-CoV

Background

Evidence points to the emergence of a novel human coronavirus, Middle East respiratory syndrome coronavirus (MERS-CoV), which causes a severe acute respiratory syndrome (SARS)-like disease. In response, the development of effective vaccines and therapeutics remains a clinical priority. To accomplish this, it is necessary to evaluate neutralizing antibodies and screen for MERS-CoV entry inhibitors.

Methods

In this study, we produced a pseudovirus bearing the full-length spike (S) protein of MERS-CoV in the Env-defective, luciferase-expressing HIV-1 backbone. We then established a pseudovirus-based inhibition assay to detect neutralizing antibodies and anti-MERS-CoV entry inhibitors.

Results

Our results demonstrated that the generated MERS-CoV pseudovirus allows for single-cycle infection of a variety of cells expressing dipeptidyl peptidase-4 (DPP4), the confirmed receptor for MERS-CoV. Consistent with the results from a live MERS-CoV-based inhibition assay, the antisera of mice vaccinated with a recombinant protein containing receptor-binding domain (RBD, residues 377–662) of MERS-CoV S fused with Fc of human IgG exhibited neutralizing antibody response against infection of MERS-CoV pseudovirus. Furthermore, one small molecule HIV entry inhibitor targeting gp41 (ADS-J1) and the 3-hydroxyphthalic anhydride-modified human serum albumin (HP-HSA) could significantly inhibit MERS-CoV pseudovirus infection.

Conclusion

Taken together, the established MERS-CoV inhibition assay is a safe and convenient pseudovirus-based alternative to BSL-3 live-virus restrictions and can be used to rapidly screen MERS-CoV entry inhibitors, as well as evaluate vaccine-induced neutralizing antibodies against the highly pathogenic MERS-CoV.

Development of anti-influenza A compounds: a pilot study

1. There is no effective anti-H5N1 avian influenza agent. 2. A chemical compound— BFDBSC—can inhibit H5N1 virus infection in cell cultures, and such inhibition might be attributable to its halogenated benzoyl residues. 3. This pilot study assessed anti- H5N1 activity and toxicity of four chemical compounds with halogenated benzoyl residues in cell culture system. 4. Two compounds—FPBFDBSC and BFB-gallate— showed higher antiviral effectsthan BFDBSC, whearas the other two—BFB-borneol and BFB-menthol—showed lower antiviral effects. These compounds did not show toxicity. 5. The halogenated benzoyl residues may play a key role in anti-H5N1 effects. However, all these compounds showed poor solubility, which may limit their utility

Leptin mediates the pathogenesis of severe 2009 pandemic influenza A(H1N1) infection associated with cytokine dysregulation in mice with diet-induced obesity

BACKGROUND

Obesity is associated with a high circulating leptin level and severe 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) infection. The mechanism for severe lung injury in obese patients and the specific treatment strategy remain elusive.

METHOD

We studied the pathogenesis of A(H1N1)pdm09 infection in a mouse model of diet-induced obesity.

RESULTS

Obese mice had significantly higher initial pulmonary viral titer and mortality after challenge with A(H1N1)pdm09, compared with age-matched lean mice. Compared with lean mice, obese mice had heightened proinflammatory cytokine and chemokine levels and more severe pulmonary inflammatory damage. Furthermore, obese mice had a higher preexisting serum leptin level but a lower preexisting adiponectin level. Recombinant mouse leptin increased the interleukin 6 (IL-6) messenger RNA expression in mouse single-lung-cell preparations, mouse macrophages, and mouse lung epithelial cell lines infected with A(H1N1)pdm09. Administration of anti-leptin antibody improved the survival of infected obese mice, with associated reductions in pulmonary levels of the proinflammatory cytokines IL-6 and interleukin 1β but not the pulmonary viral titer.

CONCLUSIONS

Our findings suggest that preexisting high levels of circulating leptin contribute to the development of severe lung injury by A(H1N1)pdm09 in mice with diet-induced obesity. The therapeutic strategy of leptin neutralization for the reduction of proinflammatory responses and pulmonary damage in obese patients warrants further investigations.

Comparative immunological evaluation of recombinant Salmonella Typhimurium strains expressing model antigens as live oral vaccines

Background

Despite the development of various systems to generate live recombinant Salmonella Typhimurium vaccine strains, little work has been performed to systematically evaluate and compare their relative immunogenicity. Such information would provide invaluable guidance for the future rational design of live recombinant Salmonella oral vaccines.

Result

To compare vaccine strains encoded with different antigen delivery and expression strategies, a series of recombinant Salmonella Typhimurium strains were constructed that expressed either the enhanced green fluorescent protein (EGFP) or a fragment of the hemagglutinin (HA) protein from the H5N1 influenza virus, as model antigens. The antigens were expressed from the chromosome, from high or low-copy plasmids, or encoded on a eukaryotic expression plasmid. Antigens were targeted for expression in either the cytoplasm or the outer membrane. Combinations of strategies were employed to evaluate the efficacy of combined delivery/expression approaches. After investigating in vitro and in vivo antigen expression, growth and infection abilities; the immunogenicity of the constructed recombinant Salmonella strains was evaluated in mice. Using the soluble model antigen EGFP, our results indicated that vaccine strains with high and stable antigen expression exhibited high B cell responses, whilst eukaryotic expression or colonization with good construct stability was critical for T cell responses. For the insoluble model antigen HA, an outer membrane expression strategy induced better B cell and T cell responses than a cytoplasmic strategy. Most notably, the combination of two different expression strategies did not increase the immune response elicited.

Conclusion

Through systematically evaluating and comparing the immunogenicity of the constructed recombinant Salmonella strains in mice, we identified their respective advantages and deleterious or synergistic effects. Different construction strategies were optimally-required for soluble versus insoluble forms of the protein antigens. If an antigen, such as EGFP, is soluble and expressed at high levels, a low-copy plasmid-cytoplasmic expression strategy is recommended; since it provokes the highest B cell responses and also induces good T cell responses. If a T cell response is preferred, a eukaryotic expression plasmid or a chromosome-based, cytoplasmic-expression strategy is more effective. For insoluble antigens such as HA, an outer membrane expression strategy is recommended.

Identification of drug resistant mutations in HIV-1 CRF07_BC variants selected by nevirapine in vitro

Since the antiretroviral therapy (ART) was introduced to patients infected by human immunodeficiency virus (HIV), the HIV related mortality and morbidity have been significantly reduced. The major obstacle for long-term successful anti-HIV treatment is the emergence of drug resistant mutants. Current data of drug resistance was mainly obtained on HIV-1 subtype B but rarely on non-B virus, even more rare with newly emerged circulating recombinant forms (CRFs). The lack of such data limits the rational management of ART for the increasing number of patients infected by non-subtype B virus. In this study, a HIV-1 CRF07_BC strain CNGZD was isolated from a HIV patient and its genome was sequenced and deposited in GenBank (JQ423923). Potential drug resistant mutants of this CRF07_BC virus strain were selected in PBMCs cultures in the presence of Nevirapine (NVP), which is the most frequently used antiretroviral drug in China. Four combination profiles of mutations were identified in the NVP-selected mutants, which were initiated with A98G, V108I, Y181C and I135T/I382L and followed by more than two other mutations at the end of the selections, respectively. A total of seven previously reported mutations (A98G, V106M, V108I, I135T, Y181C, V189I, K238N) and seven novel mutations (P4H, T48I, I178M, V314A, I382L/V, T386A) in the reverse transcriptase gene were found in these NVP-selected mutants. Phenotypic analysis in the NVP-selected mutants showed that all the mutations, except P4H, contribute to NVP resistance. Among them, V106M and Y181C reduce NVP susceptibility for more than 20-fold, while the other mutations cause less than 20 folds drug resistance. Although the information obtained in this in vitro selection study may not fully cover resistant mutations which will actually occur in patients, it has still provided useful information for rational management of ART in patients infected with HIV CRF_BC subtype.