The flavivirus membrane fusion machinery, like that of many other enveloped viruses, is triggered by the acidic pH in endosomes after virus uptake by receptor-mediated endocytosis. It has been ...hypothesized that conserved histidines in the class II fusion protein E of these viruses function as molecular switches and, by their protonation, control the fusion process. Using the mutational analysis of recombinant subviral particles of tick-borne encephalitis virus, we provide direct experimental evidence that the initiation of fusion is crucially dependent on the protonation of one of the conserved histidines (His323) at the interface between domains I and III of E, leading to the dissolution of domain interactions and to the exposure of the fusion peptide. Conserved histidines located outside this critical interface were found to be completely dispensable for triggering fusion.
After vaccination of humans with tick-borne encephalitis virus (TBEV) vaccine, the extent of crossneutralization between viruses of the European, Far Eastern, and Siberian subtypes of TBEV and Omsk ...hemorrhagic fever virus (OHFV) was analyzed. Hybrid viruses that encode the TBEV surface proteins for representative viruses within all subtypes, and OHFV, were constructed using the West Nile virus (WNV) backbone as vector. These viruses allow for unbiased head-to-head comparison in neutralization assays because they exhibit the antigenic characteristics of the TBEV strains from which the surface proteins were derived and showed equivalent biologic properties in cell culture. Human serum samples derived from a TBEV vaccine trial were analyzed and revealed comparable neutralizing antibody titers against European, Far Eastern, and Siberian subtype viruses, indicating equally potent cross-protection against these TBEV strains and a somewhat reduced but still protective neutralization capacity against more distantly related viruses, such as OHFV.
Recent data suggest that the signal transducer and activator of transcription (STAT)5 contributes to differentiation and growth of mast cells. It has also been described that constitutively ...phosphorylated STAT5 (pSTAT5) plays a pro-oncogenic role in various myeloid neoplasms. We examined the expression of pSTAT5 in neoplastic mast cells in systemic mastocytosis and asked whether the disease-related oncoprotein KIT D816V is involved in STAT5 activation. As assessed by immunohistochemistry using the anti-pSTAT5 antibody AX1, neoplastic mast cells were found to display pSTAT5 in all SM patients examined ( n = 40). Expression of pSTAT5 was also demonstrable in the KIT D816V-positive mast cell leukemia cell line HMC-1. Using various staining-protocols, pSTAT5 was found to be located in both the cytoplasmic and nuclear compartment of mast cells. To define the functional role of KIT D816V in STAT5-activation, Ba/F3 cells with doxycycline-inducible expression of KIT D816V were used. In these cells, induction of KIT D816V resulted in an increased expression of pSTAT5 without substantial increase in total STAT5. Moreover, the KIT D816V-targeting kinase-inhibitor PKC412 was found to counteract expression of pSTAT5 in HMC-1 cells as well as doxycycline-induced expression of pSTAT5 in Ba/F3 cells. Finally, a dominant negative STAT5-construct was found to inhibit growth of HMC-1 cells. Together, our data show that neoplastic mast cells express cytoplasmic and nuclear pSTAT5, that KIT D816V promotes STAT5-activation, and that STAT5-activation contributes to growth of neoplastic mast cells.
A novel avian H7N9 virus with a high case fatality rate in humans emerged in China in 2013. We evaluated the immunogenicity and protective efficacy of a candidate Vero cell culture-derived ...whole-virus H7N9 vaccine in small animal models.
Antibody responses induced in immunized DBA/2J mice and guinea pigs were evaluated by hemagglutination inhibition (HI), microneutralization (MN), and neuraminidase inhibition (NAi) assays. T-helper cell responses and IgG subclass responses in mice were analyzed by ELISPOT and ELISA, respectively. Vaccine efficacy against lethal challenge with wild-type H7N9 virus was evaluated in immunized mice. H7N9-specific antibody responses induced in mice and guinea pigs were compared to those induced by a licensed whole-virus pandemic H1N1 (H1N1pdm09) vaccine.
The whole-virus H7N9 vaccine induced dose-dependent H7N9-specific HI, MN and NAi antibodies in mice and guinea pigs. Evaluation of T-helper cell responses and IgG subclasses indicated the induction of a balanced Th1/Th2 response. Immunized mice were protected against lethal H7N9 challenge in a dose-dependent manner. H7N9 and H1N1pdm09 vaccines were similarly immunogenic.
The induction of H7N9-specific antibody and T cell responses and protection against lethal challenge suggest that the Vero cell culture-derived whole-virus vaccine would provide an effective intervention against the H7N9 virus.
Highlights ► Use of an unbiased test system for quantitative comparison of TBE vaccines. ► Efficacy against TBE viruses of Far Eastern and European suptypes was tested. ► Comparable neutralization ...titers induced by different vaccines in mouse model. ► Comparable protection from disease induced by different vaccines in mouse model. ► These data indicate equal protection provided by different vaccines tested.
This article presents a case study of RIMMF, a software tool developed to improve the orientation and training of catalogers who use Resource Description and Access (RDA) to maintain bibliographic ...data. The cataloging guidance and instructions of RDA are based on the Functional Requirements conceptual models that are now consolidated in the IFLA Library Reference Model, but many catalogers are applying RDA in systems that have evolved from inventory and text-processing applications developed from older metadata paradigms. The article describes how RIMMF interacts with the RDA Toolkit and RDA Registry to offer cataloger-friendly multilingual data input and editing interfaces.
Background
Acquired epidermal growth factor receptor
(EGFR)
T790M mutation is the primary resistance mechanism to first-generation EGFR tyrosine kinase inhibitors (TKIs) used in advanced,
EGFR
...mutation-positive non-small-cell lung cancer (NSCLC). Available data, predominantly in Asian patients, suggest that this mutation is also the major cause of resistance to the irreversible ErbB family blocker, afatinib. For
EGFR
T790M-positive patients who progress on EGFR TKI therapy, osimertinib is an effective treatment option. However, data on osimertinib use after afatinib are, to date, scarce.
Objective
To identify the prevalence of
EGFR
T790M mutations in predominantly Caucasian patients with stage IV
EGFR
mutation-positive NSCLC who progressed on afatinib, and to investigate the subsequent response to osimertinib.
Patients and Methods
In this single-center, retrospective analysis,
EGFR
T790M mutation status after afatinib failure was assessed using liquid biopsy and tissue rebiopsy.
EGFR
T790M-positive patients subsequently received osimertinib.
Results
Sixty-seven patients received afatinib in the first-, second-, or third-line (80.6%, 14.9%, and 4.5%, respectively). After afatinib failure, the T790M mutation was identified in 49 patients (73.1%). Liquid biopsy and tissue rebiopsy were concordant in 79.4% of cases. All patients with T790M-positive tumors received osimertinib (73.5% after first-line afatinib); 37 (75.5%) of these had an objective response (complete response: 22.4%; partial response: 53.1%). Response rate was independent of T790M copy number.
Conclusion
EGFR
T790M mutation is a major mechanism of acquired resistance to afatinib. Osimertinib confers high response rates after afatinib failure in
EGFR
T790M-positive patients and its use in sequence potentially allows extended chemotherapy-free treatment.
This study assessed the relationship between the medically underserviced index and stroke prevalence in upstate New York while controlling for demographic characteristics including age, education ...level, and race as well as other geographically defined variables including urban or rural status and access to healthcare. Given that stroke is one of the leading causes of death globally with over 780,000 Americans having experienced at least one stroke-related symptom as of 2020, and with medically underserviced areas in upstate New York exhibiting higher prevalence rates with limited existing research on the topic, there was a need to explore whether there was a relationship between geographical area and prevalence of stroke across various regions of the state. A secondary dataset obtained from the Center for Disease Control and Prevention (CDC) was utilized to assess the effects of the medical underserviced index. The findings were insignificant regarding the relationship between geographical area and stroke prevalence in upstate New York (p = 0.724), although several significant relationships were identified including lower levels of education attainment (p = 0.009), residing in a large central metropolitan area (p = 0.001), residing in a large fringe metropolitan area (p = 0.002), and residing in a medium or small metropolitan area (p = 0.001). The findings suggest that there is some underlying connection between the geographical location of residence and stroke prevalence, with future research needed to identify the precise latent relationship between the currently known risk factors.
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