Biology subjects

Abdullah, O.

Publications and source records attributed to Abdullah, O..

3 recordsLinked to original sources

bioRxiv2025

Emergence of an Antigenically Drifted and Reassorted Influenza B Virus at the end of the 2024-25 Influenza Season

Influenza B virus (IBV) is a significant contributor to annual and severe cases of influenza, particularly in the young and elderly. Late in the 2024-25 Northern Hemisphere influenza season, a surge of IBV cases were identified in the Johns Hopkins Hospital Systems. The IBV responsible for the surge, C.3.1/re, was a clade C.3 virus that had reassorted with clade C.5.1 viruses and acquired the D197N mutation in hemagglutinin restoring a putative N-linked glycan predicted to mask a key neutralizing antibody epitope. The C.3.1/re viruses preferentially infected children but showed no significant change in disease severity. C.3.1/re viruses were poorly neutralized by pre- and post- influenza vaccination serum in a human cohort. Removal of the glycan at residue 197 restored neutralizing antibody recognition. The C.3.1/re IBV genotype that emerged late in the 2024-25 influenza season was antigenically mismatched with IBV vaccine strains for the 2025 and 2026 Southern hemisphere, as well as the 2025-26 Northern Hemisphere influenza seasons. While the 2026-27 Northern Hemisphere vaccine strain is a C.3.1/re, the egg adapted isolate selected (B/Tokyo/EIS13-175/2025) lacks the 197 glycosylation which is predicted to have poor recognition with circulating IBV clades. Phylogenetic analysis of currently circulating IBVs shows a diversification of circulating C.3 clades with multiple reassortment events between C.3 and C.5 clades in addition to independent acquisitions of D197N mutations, suggesting IBV is going through a period of significant antigenic and genetic expansion. IMPORTANCEInfluenza B viruses are undergoing a period of antigenic and genetic expansion, with several reassorted viruses emerging that also contain point mutations in key hemagglutinin antigenic sites proximal to the receptor binding domain. This has important impacts on vaccine strain choice, as only one IBV component is included in current influenza vaccines. We demonstrate a significant shift in the demographics of IBV infected individuals with the emergence of the antigenically drifted and reassorted IBV C.3.1/re. Furthermore, we show that 197 glycosylation of hemagglutinin is critical for C.3.1/re antigenic drift and we document several emergent C.3 reassortments encoding the D197N mutation. With the IBV vaccine component for the Northern Hemisphere 2026-27 season having lost a key N-linked glycan on the hemagglutinin protein, and multiple independent emergences of antigenically drifted and reassorted viruses, attention to IBV infections should be increased in the upcoming Southern and Northern hemisphere influenza seasons.

microbiology↗

bioRxiv2023

pH-responsive upconversion mesoporous silica nanospheres for combined multimodal diagnostic imaging and targeted photodynamic and photothermal cancer therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) have garnered considerable interest as non-invasive cancer treatment modalities. However, these approaches remain limited by low solubility, poor stability and inefficient targeting of many common photosensitizers (PSs) and photothermal agents (PTAs). To overcome these limitations, we have designed biocompatible and biodegradable tumor-targeted upconversion nanospheres with imaging capabilities. The multifunctional nanospheres consist of a sodium yttrium fluoride core doped with lanthanides (ytterbium, erbium and gadolinium) and bismuth selenide (NaYF4:Yb/Er/Gd,Bi2Se3) within a mesoporous silica shell that encapsulates a PS, Chlorin e6 (Ce6), in its pores. NaYF4:Yb/Er converts deeply penetrating near-infrared (NIR) light to visible light, which excites the Ce6 to generate cytotoxic reactive oxygen species (ROS), while the PTA Bi2Se3 efficiently converts absorbed NIR light to heat. Additionally, Gd enables magnetic resonance imaging (MRI) of the nanospheres. The mesoporous silica shell is coated with lipid/polyethylene glycol (DPPC/cholesterol/DSPE-PEG) to ensure retention of the encapsulated Ce6 and minimize interactions with serum proteins and macrophages that impede tumor targeting. Finally, the coat is functionalized with the acidity-triggered rational membrane (ATRAM) peptide, which promotes specific and efficient internalization into cancer cells within the mildly acidic tumor microenvironment. Following uptake by cancer cells in vitro, NIR laser irradiation of the nanospheres caused substantial cytotoxicity due to ROS production and hyperthermia. The nanospheres facilitated tumor MRI and thermal imaging, and exhibited potent NIR laser light-induced antitumor effects in vivo via combined PDT and PTT, with no observable toxicity to healthy tissue, thereby substantially prolonging survival. Our results demonstrate that the ATRAM-functionalized, lipid/PEG-coated upconversion mesoporous silica nanospheres (ALUMSNs) offer multimodal diagnostic imaging and targeted combinatorial cancer therapy.

bioengineering↗

bioRxiv2020

From letters to composed concepts: A magnetoencephalography study of reading

Language comprehension requires the recognition of individual words and the combination of their meanings to yield complex concepts or interpretations. Rather than simple concatenation, this combinatory process often requires the insertion of unstated semantic material between words, based on thematic or feature knowledge of the concepts. For example, the phrase horse barn is not interpreted as a blend of a horse and a barn, but specifically a barn in which horses are kept. Mounting evidence suggests two cortical semantic hubs, in left temporoparietal and anterior temporal cortex, underpin thematic and feature concept knowledge, but much remains unclear about how these putative hubs contribute to combinatory language processing. Using magnetoencephalography, we contrasted source-localized responses to modifier-noun phrases involving thematic relations vs. feature modifications, while also examining how lower-level orthographic processing fed into responses supporting word combination. Twenty-eight participants completed three procedures examining responses to letter-strings, adjective-noun phrases, and noun-noun combinations that varied the semantic relations between words. We found that while color + noun phrases engaged the left anterior temporal lobe (150-300 ms after phrasal head), posterior temporal lobe (150-300 ms), and angular gyrus (300-450 ms), only left posterior temporal lobe responses were sensitive to implicit thematic relations between composing nouns (150-300 ms). We additionally identified a left temporo-occipital progression from orthographic to lexical processing, feeding into ventral anterior areas engaged in the combination of word meanings. Finally, by examining source signal leakage, we characterized the degree to which these responses could be distinguished from one another, using linear source estimation.

neuroscience↗