Mosquito-borne chikungunya virus (CHIKV) is a positive-sense, single-stranded RNA virus from the genus Alphavirus, family Togaviridae, which causes fever, rash and severe persistent polyarthralgia in ...humans. Since there are currently no FDA licensed vaccines or antiviral therapies for CHIKV, the development of vaccine candidates is of critical importance. Historically, live-attenuated vaccines (LAVs) for protection against arthropod-borne viruses have been created by blind cell culture passage leading to attenuation of disease, while maintaining immunogenicity. Attenuation may occur via multiple mechanisms. However, all examined arbovirus LAVs have in common the acquisition of positively charged amino acid substitutions in cell-surface attachment proteins that render virus infection partially dependent upon heparan sulfate (HS), a ubiquitously expressed sulfated polysaccharide, and appear to attenuate by retarding dissemination of virus particles in vivo. We previously reported that, like other wild-type Old World alphaviruses, CHIKV strain, La Réunion, (CHIKV-LR), does not depend upon HS for infectivity. To deliberately identify CHIKV attachment protein mutations that could be combined with other attenuating processes in a LAV candidate, we passaged CHIKV-LR on evolutionarily divergent cell-types. A panel of single amino acid substitutions was identified in the E2 glycoprotein of passaged virus populations that were predicted to increase electrostatic potential. Each of these substitutions was made in the CHIKV-LR cDNA clone and comparisons of the mutant viruses revealed surface exposure of the mutated residue on the spike and sensitivity to competition with the HS analog, heparin, to be primary correlates of attenuation in vivo. Furthermore, we have identified a mutation at E2 position 79 as a promising candidate for inclusion in a CHIKV LAV.
CD47 is a signaling receptor for thrombospondin-1 and the counter-receptor for signal-regulatory protein-α (SIRPα). By inducing inhibitory SIRPα signaling, elevated CD47 expression by some cancers ...prevents macrophage phagocytosis. The anti-human CD47 antibody B6H12 inhibits tumor growth in several xenograft models, presumably by preventing SIRPα engagement. However, CD47 signaling in nontransformed and some malignant cells regulates self-renewal, suggesting that CD47 antibodies may therapeutically target cancer stem cells (CSCs). Treatment of MDA-MB-231 breast CSCs with B6H12 decreased proliferation and asymmetric cell division. Similar effects were observed in T47D CSCs but not in MCF7 breast carcinoma or MCF10A breast epithelial cells. Gene expression analysis in breast CSCs treated with B6H12 showed decreased expression of epidermal growth factor receptor (EGFR) and the stem cell transcription factor KLF4. EGFR and KLF4 mRNAs are known targets of microRNA-7, and B6H12 treatment correspondingly enhanced microRNA-7 expression in breast CSCs. B6H12 treatment also acutely inhibited EGF-induced EGFR tyrosine phosphorylation. Expression of B6H12-responsive genes correlated with CD47 mRNA expression in human breast cancers, suggesting that the CD47 signaling pathways identified in breast CSCs are functional in vivo. These data reveal a novel SIRPα-independent mechanism by which therapeutic CD47 antibodies could control tumor growth by autonomously forcing differentiation of CSC.
Factors that contribute to enhanced susceptibility to severe bacterial disease after influenza virus infection are not well defined but likely include the microbiome of the respiratory tract. ...Vaccination against influenza, while having variable effectiveness, could also play a role in microbial community stability. We collected nasopharyngeal samples from 215 individuals infected with influenza A/H3N2 or influenza B virus and profiled the microbiota by target sequencing of the 16S rRNA gene. We identified signature taxonomic groups by performing linear discriminant analysis and effective size comparisons (LEfSe) and defined bacterial community types using Dirichlet multinomial mixture (DMM) models. Influenza infection was shown to be significantly associated with microbial composition of the nasopharynx according to the virus type and the vaccination status of the patient. We identified four microbial community types across the combined cohort of influenza patients and healthy individuals with one community type most representative of the influenza virus-infected group. We also identified microbial taxa for which relative abundance was significantly higher in the unvaccinated elderly group; these taxa include species known to be associated with pneumonia.
Our results suggest that there is a significant association between the composition of the microbiota in the nasopharynx and the influenza virus type causing the infection. We observe that vaccination status, especially in more senior individuals, also has an association with the microbial community profile. This indicates that vaccination against influenza, even when ineffective to prevent disease, could play a role in controlling secondary bacterial complications.
About the Authors: Katherine E. E. Johnson Affiliation: Center for Genomics & Systems Biology, Department of Biology, New York University, New York, New York, United States of America ORCID ...http://orcid.org/0000-0002-9226-0672 Timothy Song Affiliation: Center for Genomics & Systems Biology, Department of Biology, New York University, New York, New York, United States of America ORCID http://orcid.org/0000-0001-6932-0916 Benjamin Greenbaum Affiliation: Tisch Cancer Institute, Departments of Genetics and Genomics, Medicine, Oncological Sciences, and Pathology, Icahn School of Medicine of Mt Sinai, New York, New York, United States of America Elodie Ghedin * E-mail: elodie.ghedin@nyu.edu Affiliations Center for Genomics & Systems Biology, Department of Biology, New York University, New York, New York, United States of America, Department of Epidemiology, College of Global Public Health, New York University, New York, New York, United States of America ORCID http://orcid.org/0000-0002-1515-725XCitation: Johnson KEE, Song T, Greenbaum B, Ghedin E (2017) Getting the flu: 5 key facts about influenza virus evolution. Influenza A appears to be evolving under pressure to avoid CpG-containing oligonucleotides, possibly due to innate immune recognition, in a manner less present in influenza B evolution 21, 22. ...influenza B lineages have been shown to have lower rates of antigenic drift when compared to influenza A subtypes 23. ...the intrinsic diversity and loose transmission bottlenecks in circulating influenza populations can facilitate an increase in pathogenesis by allowing viral variants to cooperate with one another or by increasing the number of beneficial mutations appearing in cocirculating clones. Effective vaccination strategies would require a better understanding of the complex interplay of multivariant transmission dynamics, inter- and intrahost viral evolution, and the interaction of diverse strains with the host immune system.
Resistance following antiviral therapy is commonly observed in human influenza viruses. Although this evolutionary process is initiated within individual hosts, little is known about the pattern, ...dynamics, and drivers of antiviral resistance at this scale, including the role played by reassortment. In addition, the short duration of human influenza virus infections limits the available time window in which to examine intrahost evolution. Using single-molecule sequencing, we mapped, in detail, the mutational spectrum of an H3N2 influenza A virus population sampled from an immunocompromised patient who shed virus over a 21-month period. In this unique natural experiment, we were able to document the complex dynamics underlying the evolution of antiviral resistance. Individual resistance mutations appeared weeks before they became dominant, evolved independently on cocirculating lineages, led to a genome-wide reduction in genetic diversity through a selective sweep, and were placed into new combinations by reassortment. Notably, despite frequent reassortment, phylogenetic analysis also provided evidence for specific patterns of segment linkage, with a strong association between the hemagglutinin (HA)- and matrix (M)-encoding segments that matches that previously observed at the epidemiological scale. In sum, we were able to reveal, for the first time, the complex interaction between multiple evolutionary processes as they occur within an individual host.
Understanding the evolutionary forces that shape the genetic diversity of influenza virus is crucial for predicting the emergence of drug-resistant strains but remains challenging because multiple processes occur concurrently. We characterized the evolution of antiviral resistance in a single persistent influenza virus infection, representing the first case in which reassortment and the complex patterns of drug resistance emergence and evolution have been determined within an individual host. Deep-sequence data from multiple time points revealed that the evolution of antiviral resistance reflects a combination of frequent mutation, natural selection, and a complex pattern of segment linkage and reassortment. In sum, these data show how immunocompromised hosts may help reveal the drivers of strain emergence.
The Nyamiviridae is a family of viruses with unsegmented, negative-sense RNA genomes of 11.3-12.2 kb that produce enveloped, spherical virions. Viruses of the genus Nyavirus are tick-borne and some ...also infect birds. Other nyamiviruses infecting parasitoid wasps and plant parasitic nematodes have been classified into the genera Peropuvirus and Socyvirus, respectively. This is a summary of the current International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of Nyamiviridae, which is available at www.ictv.global/report/nyamiviridae.
Aim
Whole brain radiotherapy (WBRT) is commonly used to treat brain metastases (BM) from nonsmall cell lung cancer (NSCLC). Its utility is increasingly being questioned after a recent randomized ...trial (QUARTZ) showed that its omission did not significantly impact the survival or quality of life of their patients recruited from UK and Australian centers. We report the patient characteristics and survival outcomes of our local population in comparison with theirs.
Methods
Medical records of patients who received WBRT in two tertiary hospitals over 18 months were reviewed. Characteristics and survival outcomes of patient with NSCLC receiving WBRT for the first time were evaluated. Patients with prior excision of BM or stereotactic radiotherapy were excluded. Treatment details including radiotherapy dose and use of tyrosine kinase inhibitors (TKIs) were recorded.
Results
Between January 2015 and June 2016, 116 patients with NSCLC received WBRT for their BM. Their median age was 65 years (range, 36‐85) and median follow‐up duration was 110 days (range, 14‐840). A total of 102 (88%) patients had their driver mutation tested of which 59 (58%) were epidermal growth factor receptor (EGFR) mutants. Factors predicting for better survival were female gender (P < .001), EGFR mutant receiving TKIs (P = .013), prescription other than 20 Gray in five fractions (P = .003), and presence of more than four BM (P = .001).
Conclusion
Our patients appear to be considerably different from those recruited into the QUARTZ trial. Further prospective studies should be done to evaluate the value of WBRT in our population.
Influenza A virus is characterized by high genetic diversity. However, most of what is known about influenza evolution has come from consensus sequences sampled at the epidemiological scale that only ...represent the dominant virus lineage within each infected host. Less is known about the extent of within-host virus diversity and what proportion of this diversity is transmitted between individuals. To characterize virus variants that achieve sustainable transmission in new hosts, we examined within-host virus genetic diversity in household donor-recipient pairs from the first wave of the 2009 H1N1 pandemic when seasonal H3N2 was co-circulating. Although the same variants were found in multiple members of the community, the relative frequencies of variants fluctuated, with patterns of genetic variation more similar within than between households. We estimated the effective population size of influenza A virus across donor-recipient pairs to be approximately 100-200 contributing members, which enabled the transmission of multiple lineages, including antigenic variants.
To evaluate the effect of compressed SENSE (CS) in clinical settings on scan time reduction and image quality.
Ninety-five magnetic resonance imaging (MRI) scans from different anatomical regions ...were acquired, consisting of a standard protocol sequence (SS) and sequence accelerated with CS. Anonymized paired sequences were randomly displayed and rated by six blinded subspecialty radiologists. Side-by-side evaluation on perceived sharpness, perceived signal-to-noise-ratio (SNR), lesion conspicuity, and artifacts were compared and scored on a five-point Likert scale, and individual image quality was evaluated on a four-point Likert scale.
CS reduced overall scan time by 32% while maintaining acceptable MRI quality for all regions. The largest time savings were seen in the spine (mean = 68 seconds, 44% reduction) followed by the brain (mean = 86 seconds, 37% reduction). The sequence with maximum time savings was intracranial 3D-time-of-flight magnetic resonance angiography (202 seconds, 56% reduction). CS was mildly inferior to SS on perceived sharpness, perceived SNR, and lesion conspicuity (mean scores = 2.32-2.96, P < .001 1: SS superior; 3: equivalent; 5: CS superior). CS was equivalent to SS for joint and body scans on overall image quality (CS = 3.02-3.37, SS = 3.04-3.68, P > .05, 1: lowest quality and 4: highest quality). The overall image quality of CS was slightly less for brain and spine scans (mean CS = 2.79-3.05, mean SS = 3.13-3.43, P = .021) but still diagnostic. Good overall clinical acceptance for CS (88%) was noted with full clinical acceptance for body scans (100%) and high acceptance for other regions (68%-95%).
CS significantly reduced MR acquisition time while maintaining acceptable image quality. The implementation of CS may improve departmental workflows and enhance patient care.
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