Search Results (9)

In recent years, the four main swine influenza A virus (IAV-S) subtypes circulating in swine in the EU have been H1avN1, H1huN2, H1N1pdm09, and H3N2. The latter emerged in 1984 from a reassortment event between a human seasonal H3N2 and H1avN1, and is currently detected at low prevalence in swine in Italy. Here, we describe nine H3N2 IAV-S isolates belonging to three novel genotypes, first detected in Italy in 2021, likely resulting from reassortment events between swine and human IAVs. The first genotype was characterized by a hemagglutinin (H3 HA) of human seasonal origin, a neuraminidase (N2 NA) derived from H1huN2 strains circulating in Italian swine, and an avian-like internal gene cassette (IGC). The second genotype differed in its IGC constellation: PB2, PB1, PA and NP segments were of pandemic origin (pdm09), while NS and M segments derived from the Eurasian avian-like lineage. The third genotype combined a human-derived H3, a Gent/84-derived N2, and a pdm09-origin IGC, except for an avian-like NS. This study aimed to characterize the genetic features of these novel H3huN2 and assess their epidemiological relevance, with implications for surveillance and control, improving preparedness and mitigating the risks posed by zoonotic influenza viruses. Full article

Introduction: Immune checkpoint blockers have revolutionized the first-line treatment of advanced non-small-cell lung cancer (NSCLC). Pembrolizumab, an anti-PD-1 monoclonal antibody, is a standard therapy either alone or in combination with chemotherapy (chemo-IO). The current study explores the efficacy and safety of pembrolizumab with carboplatin and weekly paclitaxel in a cohort of frail patients. Methods: A monocentric retrospective study was conducted between 22 September 2020 and 19 January 2023 regarding patients with stage IV NSCLC treated with chemo-IO combination: carboplatin (AUC 5 mg/mL/min; Q4W), weekly paclitaxel (90 mg/m² on days 1, 8, and 15), and pembrolizumab (200 mg Q4W). The primary objective was real-world progression-free survival (rwPFS). Secondary objectives were overall survival (OS), toxicity profile, and outcomes based on histological subtype. Results: A total of 34 patients (20 squamous and 14 non-squamous NSCLC) benefited from the chemo-IO regimen for frail patients; 41.9% had an ECOG-PS = 2. The median age was 75.5 years. We observed an overall response rate (ORR) of 55.9%. Notably, squamous NSCLC exhibited a significantly higher ORR (80%) than non-squamous NSCLC (21.4%); p = 0.001. The median rw-PFS was 10.6 months (95% CI [6.0, NA]), with 6- and 12-month rw-PFS rates of 69% and 45.8%, respectively. The median OS was not reached, with 12- and 18-month OS rates of 75.6% and 61.4%, respectively. The median number of maintenance cycles of pembrolizumab was 5 (0; 27). Nine patients (26.5%) experienced a toxicity related to chemotherapy leading to a reduction of the dose administered and, in five patients (14.7%), to the permanent discontinuation of chemotherapy. Six patients (17.6%) had an immune-related adverse event leading to the discontinuation of immunotherapy. Discussion: Pembrolizumab plus carboplatin and weekly paclitaxel demonstrates promising efficacy and safety in frail patients with metastatic NSCLC, especially for ORR in sq-NSCLC. Prospective studies focusing on frail populations are warranted in order to validate these findings and optimize therapeutic strategies in the first-line setting. Full article

H5, H7 and H9 are the most important subtypes of avian influenza viruses (AIVs), and nine neuraminidase (NA) subtypes (N1–N9) of AIVs have been identified in poultry. A method that can simultaneously detect H5, H7, H9 and the nine NA subtypes of AIVs would save time and effort. In this study, 13 pairs of primers, including 12 pairs of subtype-specific primers for detecting particular subtypes (H5, H7, H9 and N1–N9) and one pair of universal primers for detecting all subtypes of AIVs, were designed and screened. The 13 pairs of primers were mixed in the same reaction, and the 13 target genes were simultaneously detected. A GeXP assay using all 13 pairs of primers to simultaneously detect H5, H7, H9 and the nine NA subtypes of AIVs was developed. The GeXP assay showed specific binding to the corresponding target genes for singlet and multiplex templates, and no cross-reactivity was observed between AIV subtypes and other related avian pathogens. Detection was observed even when only 10² copies of the 13 target genes were present. This study provides a high-throughput, rapid and labor-saving GeXP assay for the simultaneous rapid identification of three HA subtypes (H5, H7 and N9) and nine NA subtypes (N1–N9) of AIVs. Full article

The COVID-19 pandemic had a profound impact on influenza activity worldwide. However, as the pandemic progressed, influenza activity resumed. Here, we describe the influenza epidemic of high intensity of the 2022–2023 season. The epidemic had an early start and peaked in week 51.2022. The extremely high intensity of the epidemic may have been due to a significant decrease in herd immunity. The results of PCR-testing of 220,067 clinical samples revealed that the influenza A(H1N1)pdm09 virus dominated, causing 56.4% of positive cases, while A(H3N2) influenza subtype accounted for only 0.6%, and influenza B of Victoria lineage—for 34.3%. The influenza vaccine was found to be highly effective, with an estimated effectiveness of 92.7% in preventing admission with laboratory-confirmed influenza severe acute respiratory illness (SARI) cases and 54.7% in preventing influenza-like illness/acute respiratory illness (ILI/ARI) cases due to antigenic matching of circulated viruses with influenza vaccine strains for the season. Full genome next-generation sequencing of 1723 influenza A(H1N1)pdm09 viruses showed that all of them fell within clade 6B.1A.5.a2; nine of them possessed H275Y substitution in the NA gene, a genetic marker of oseltamivir resistance. Influenza A(H3N2) viruses belonged to subclade 3C.2a1b.2a.2 with the genetic group 2b being dominant. All 433 influenza B viruses belonged to subclade V1A.3a.2 encoding HA1 substitutions A127T, P144L, and K203R, which could be further divided into two subgroups. None of the influenza A(H3N2) and B viruses sequenced had markers of resistance to NA inhibitors. Thus, despite the continuing circulation of Omicron descendant lineages, influenza activity has resumed in full force, raising concerns about the intensity of fore coming seasonal epidemics. Full article

Presence of a large foreign workforce and the annual gathering of people for pilgrimage from around the globe have significantly contributed to the emergence and diversity of respiratory viruses in Saudi Arabia. Here, we report the sequence and phylogenetic analysis of the H3N2 subtype of influenza A virus (IAV) in clinical samples collected from Riyadh, Saudi Arabia. Based on RT-PCR, IAV was found in 88 (28.3%) of the 311 samples screened. Of the 88-IAV positive samples, 43 (48.8%) were H1N1 subtype while the remaining 45 (51.2%) were found to be of the H3N2 subtype. Complete sequencing of HA and NA genes of H3N2 revealed, twelve and nine amino acid (AA) substitutions respectively, and importantly, these variations are absent in the current vaccine strains. Based on the phylogenetic analysis, the majority of H3N2 strains were grouped in the same clades as the vaccine strains. Importantly, the N-glycosylation sites at AA 135(NSS) were found to be unique to 6 strains in the investigated HA1 protein and were absent in the current vaccine strains. These data may have significant clinical implications in designing novel and population-based vaccines for IAV and underscore the need for regular monitoring of efficacy of vaccines due to emerging variants. Full article

In a total of 1536 blood serum samples analysed by ELISA, antibodies for IAV nucleoprotein (NP) were detected in 30.3%. Results from HI show that the most common subtype of swIAV in the Croatian pig population was H1N1 (44.6%), followed by H3N2 (42.7%) and H1N2 (26.3%). Antibodies to at least one subtype were detected in 62.19% of blood serum samples. Detection of swIAV antigen was performed by IHC and detected in 8 of 28 lung samples collected post-mortem. The matrix (M) gene was detected in nine of one hundred and forty-two lung tissue samples and in seven of twenty-nine nasopharyngeal swabs. Phylogenetic analysis of amplified HA and NA gene fragments in Croatian isolates suggests the presence of swIAV H1avN1av. Full article

The recently discovered 340-cavity in influenza neuraminidase (NA) N6 and N7 subtypes has introduced new possibilities for rational structure-based drug design. However, the plasticity of the 340-loop (residues 342–347) and the role of the 340-loop in NA activity and substrate binding have not been deeply exploited. Here, we investigate the mechanism of 340-cavity formation and demonstrate for the first time that seven of nine NA subtypes are able to adopt an open 340-cavity over 1.8 μs total molecular dynamics simulation time. The finding that the 340-loop plays a role in the sialic acid binding pathway suggests that the 340-cavity can function as a druggable pocket. Comparing the open and closed conformations of the 340-loop, the side chain orientation of residue 344 was found to govern the formation of the 340-cavity. Additionally, the conserved calcium ion was found to substantially influence the stability of the 340-loop. Our study provides dynamical evidence supporting the 340-cavity as a druggable hotspot at the atomic level and offers new structural insight in designing antiviral drugs. Full article

Toxins modulating Na_V channels are the most abundant and studied peptide components of sea anemone venom. Three type-II toxins, δ-SHTX-Hcr1f (= RpII), RTX-III, and RTX-VI, were isolated from the sea anemone Heteractis crispa. RTX-VI has been found to be an unusual analog of RTX-III. The electrophysiological effects of Heteractis toxins on nine Na_V subtypes were investigated for the first time. Heteractis toxins mainly affect the inactivation of the mammalian Na_V channels expressed in the central nervous system (Na_V1.1–Na_V1.3, Na_V1.6) as well as insect and arachnid channels (BgNa_V1, VdNa_V1). The absence of Arg13 in the RTX-VI structure does not prevent toxin binding with the channel but it has changed its pharmacological profile and potency. According to computer modeling data, the δ-SHTX-Hcr1f binds within the extracellular region of the rNa_V1.2 voltage-sensing domain IV and pore-forming domain I through a network of strong interactions, and an additional fixation of the toxin at the channel binding site is carried out through the phospholipid environment. Our data suggest that Heteractis toxins could be used as molecular tools for Na_V channel studies or insecticides rather than as pharmacological agents. Full article

Avian influenza A virus comprises sixteen hemagglutinin (HA) and nine neuraminidase (NA) subtypes (N1–N9). To isolate llama single-domain antibody fragments (VHHs) against all N subtypes, four llamas were immunized with mixtures of influenza viruses. Selections using influenza virus yielded predominantly VHHs binding to the highly immunogenic HA and nucleoprotein. However, selection using enzymatically active recombinant NA (rNA) protein enabled us to isolate NA binding VHHs. Some isolated VHHs cross-reacted to other N subtypes. These were subsequently used for the capture of N subtypes that could not be produced as recombinant protein (rN6) or were enzymatically inactive (rN1, rN5) in phage display selection, yielding novel VHHs. In total we isolated 188 NA binding VHHs, 64 of which were expressed in yeast. Most VHHs specifically recognize a single N subtype, but some VHHs cross-react with other N-subtypes. At least one VHH bound to all N subtypes, except N4, identifying a conserved antigenic site. Thus, this work (1) describes methods for isolating NA binding VHHs, (2) illustrates the suitability of llama immunization with multiple antigens for retrieving many binders against different antigens and (3) describes 64 novel NA binding VHHs, including a broadly reactive VHH, which can be used in various assays for influenza virus subtyping, detection or serology. Full article