H1N1 Strain Research Articles

Dissecting Immunological Mechanisms Underlying Influenza Viral Nucleoprotein-induced Mucosal Immunity Against Diverse Viral Strains

The nucleoprotein (NP) of type A influenza virus (IAV) is highly conserved across all virus strains, making it an attractive candidate antigen for universal vaccines. While various studies have explored NP-induced mucosal immunity, here we interrogated the mechanistic differences between intramuscular (IM) and intranasal (IN) delivery of a recombinant adenovirus carrying NP fused with a bifunctional CD40 ligand. Despite being less effective than IM delivery in inducing systemic cellular immune responses and antibody-dependent cellular cytotoxicity (ADCC), IN immunization elicited superior antigen-specific recall humoral and cellular response in the nasal associated lymphoid tissue (NALT) of the upper respiratory tract, the initial site of immune recognition and elimination of inhaled pathogens. IN vaccination also induced significantly stronger pulmonary T cell responses in the lower respiratory tract than IM vaccination, in particular the CD8 T cells. Moreover, blocking lymphocyte circulation abrogated IM but not IN immunization induced protection, illustrating the critical role of local memory immune response upon viral infection. Notably, the CD40-targeted nasal delivery not only improved the magnitude but also the breadth of protection, including against lethal challenge with a newly isolated highly pathogenic avian H5N1 strain. These findings are informative for the design of universal mucosal vaccines, where the predominant mode of protection is independent of neutralizing antibodies.

Features of influenza virus hemagglutinin genes and their recoding possibilities

The world has already entered the stage of increasing odds for a new pandemic, which prompts to seek out for new flu vaccines, because existing vaccines demonstrate only suboptimal effectiveness. With the Covid-19 pandemic, the possibility of using mRNA vaccines has been opened up, and a prospect of finding hemagglutinin (HA) gene mRNA-based new influenza vaccines seems very attractive. As a rule, the mRNA vaccine is a product of recoding, which ensures the mRNA stability. However, the results of mRNA recoding can be ambiguous. The purpose of this report is to analyze the features of genes and proteins and to consider opportunities and limitations in their recoding. Primary structures of NA proteins and relevant genes were retrieved from Internet publicly available databases. The amino acid composition and frequency of dipeptides, nucleotide and dinucleotide compositions, %GC, translational code and compositions of neighboring di- and tricodones, distribution along primary structure for explicit and synonymous mutations were determined. H1N1 and H3N2 subtypes have both specific and general features (limitations) in their genes, differing not only in the number of protein substitutions, but also in the number and distribution of gene synonymous codons, which do not manifest in the protein primary structure, but appear, apparently, as a hidden factor, which causes the low effectiveness of classical influenza vaccines. The identification of several limitations in gene structure suggests that its any modification (in any gene) must not contradict each of the restrictions established by nature. The frequency of CpG dinucleotides in all studied strains is low, but a potential for optimizing it in H1N1 strains due to the prohibition of the quartet in the gene for arginine-encoding codons is especially limited and can be implemented through synonymous codons of other amino acids (alanine, proline, threonine or serine). Compared to the H1N1 subtype, the H3N2 subtype can be expected to have more possibilities in constructing stable NA gene mRNA.

Protective Impact of Influenza Vaccination on Healthcare Workers

Background: Influenza vaccine uptake among healthcare workers is crucial for preventing influenza infections, yet its effectiveness needs further investigation. Objectives: This prospective observational study aimed to assess the protective effect of influenza vaccination among healthcare workers in Shenzhen. Methods: We enrolled 100 participants, with 50 receiving the 2023–2024 quadrivalent influenza vaccine (QIV) and 50 serving as unvaccinated controls. Epidemiological data were collected when the participants presented influenza-like illness. Serum samples were collected at three time points (pre-vaccination and 28 and 180 days after vaccination). Hemagglutination inhibition (HI) assay was performed against the strains included in the 2023–2024 QIV (H1N1, H3N2, BV and BY strains) to assess antibody protection levels. Demographics comparisons revealed no significant differences between the vaccinated and control groups (p > 0.05), ensuring group comparability. Results: The incidence of influenza-like illness was significantly lower in the vaccinated (18%) compared to the control group (36%; p = 0.046; OR = 0.39; 95% CI: 0.15 to 0.98). The vaccinated group also exhibited a higher rate of consecutive two-year vaccinations (48% vs. 24% in the control group, p < 0.05). Additionally, the vaccinated healthcare workers were more inclined to recommend vaccination to their families (80% vs. 48%, p < 0.05). HI titers against H1N1 (p < 0.01), H3N2 (p < 0.01), BV (p < 0.001) and BY (p < 0.01) significantly increased in the vaccinated group at 28 days post-vaccination. Moreover, a marked and sustained increase in HI titers against the H3N2 strain (p < 0.001) was observed at 180 days post-vaccination, highlighting the vaccine’s enduring impact on the immune response. The fold change in the HI titers, indicative of the magnitude of the immune response, was significantly higher for H1N1 (p < 0.01), H3N2 (p < 0.001), BV (p < 0.01) and BY (p < 0.05) among the vaccinated individuals compared to the control group, underscoring the vaccine’s efficacy in eliciting a robust and sustained antibody response. Conclusion: Influenza vaccination significantly reduces the incidence of influenza-like illness among healthcare workers and promotes a sustained immune response. The study supports the importance of annual vaccination for this group to enhance personal and public health.

Immune History Modifies Disease Severity to HPAI H5N1 Clade 2.3.4.4b Viral Challenge.

The most recent outbreak of highly pathogenic avian H5 influenza (HPAI) virus in cattle is now widespread across the U.S. with spillover events happening to other mammals, including humans. Several human cases have been reported with clinical signs ranging from conjunctivitis to respiratory illness. However, most of those infected report mild to moderate symptoms, while previously reported HPAI H5Nx infections in humans have had mortality rates upwards of 50%. We recently reported that mice with pre-existing immunity to A/Puerto Rico/08/1934 H1N1 virus were protected from lethal challenge from highly pathogenic clade 2.3.4.4b H5N1 influenza virus. Here, we demonstrate that mice infected with the 2009 pandemic H1N1 virus strain A/California/04/2009 (Cal09) or vaccinated with a live-attenuated influenza vaccine (LAIV) were moderately-to-highly protected against a lethal A/bovine/Ohio/B24OSU-439/2024 H5N1 virus challenge. We also observed that ferrets with mixed pre-existing immunity-either from LAIV vaccination and/or from Cal09 infection-showed protection against a HPAI H5N1 clade 2.3.4.4b virus isolated from a cat. Notably, this protection occurred independently of any detectable hemagglutination inhibition titers (HAIs) against the H5N1 virus. To explore factors that may contribute to protection, we conducted detailed T cell epitope mapping using previously published sequences from H1N1 strains. This analysis revealed a high conservation of amino acid sequences within the internal proteins of our bovine HPAI H5N1 virus strain. These data highlight the necessity to explore additional factors that contribute to protection against HPAI H5N1 viruses, such as memory T cell responses, in addition to HA-inhibition or neutralizing antibodies.

Comparison of immunogenicity of adjuvanted and high dose influenza vaccination in long-term care facility residents.

The CDC recommends the more immunogenic adjuvanted and high-dose flu vaccines over standard-dose, non-adjuvanted vaccines for individuals above 65 years old. The current study compares adjuvanted trivalent inactivated flu vaccine (aTIV, FLUAD) versus high-dose flu vaccine (HD-IIV3, FLUZONE HD) to determine if they met non-inferiority standards for older long-term care facility (LTCF) residents. We collected blood from long-term care facility residents participating in a randomized 1:1 active control trial comparing MF59C.1 adjuvanted trivalent inactivated flu vaccine, aTIV versus HD-IIV3 over the course of two flu seasons, 2018-2019 and 2019-2020 (Trial, NCT03694808 ). We assessed humoral immunity at set time points via hemagglutinin inhibition assays (HAI) and anti-neuraminidase (enzyme-linked lectin assays (ELLA)). The recombinant influenza vaccine (RIV, Flublok) was assessed similarly in year two for a small number of participants who were carried over from year 1 (n=32). We enrolled 387 volunteers and administered either aTIV (n=194), HD-IIV3 (n=193) over the course of the 2018-2019 and 2019-2020 flu seasons. Among those enrolled and randomized in year one, a subset were administered RIV and studied in year two (n = 32). At 28 days post-vaccination, aTIV exhibited non-inferiority to HD-IIV3 for HAI for both H1N1 and H3N2 strains (GMT ratios (95% CI) for HD-IIV3/aTIV of 1.03(0.76, 1.4) and 1.04(0.73, 1.48), respectively; both 95% CI upper bounds < 1.5 to meet non-inferiority criteria) but not for Influenza B (GMT ratio (95% CI) = 1.21 (0.91, 1.61)). Non-inferiority criteria for HAI seroconversion were not met for any of the three strains. Applying the same non-inferiority criteria to neuraminidase inhibition (NI), both day 28 titer and seroconversion in aTIV were non-inferior to HD-IIV3 for H1N1 and H3N2 strains. Both aTIV and HD-IIV3 elicited similar immune responses with robust antibody responses. For the primary outcome, aTIV is non-inferior to HD-IIV3 for HAI titer of H1N1 and H3N2 but failed to meet non-inferiority criteria for Influenza B and seroconversion for all assessed strains. For the secondary outcome, aTIV was non-inferior to HD-IIV3 for both titer and seroconversion of anti-neuraminidase for both H1N1 and H3N2.

Heterozygous and generalist MxA super-restrictors overcome breadth-specificity tradeoffs in antiviral restriction.

Antiviral restriction factors such as MxA (myxovirus resistance protein A) inhibit a broad range of viruses. However, they face the challenge of maintaining this breadth as viruses evolve to escape their defense. Viral escape drives restriction factors to evolve rapidly, selecting for amino acid changes at their virus-binding interfaces to regain defense. How do restriction factors balance the breadth of antiviral functions against the need to evolve specificity against individual escaping viruses? We explored this question in human MxA, which uses its rapidly evolving loop L4 as the specificity determinant for orthomyxoviruses such as THOV and IAV. Previous combinatorial mutagenesis of rapidly evolving residues in human MxA loop L4 revealed variants with a ten-fold increase in potency against THOV. However, this strategy did not yield improved IAV restriction, suggesting a strong tradeoff between antiviral specificity and breadth. Here, using a modified combinatorial mutagenesis strategy, we find 'super-restrictor' MxA variants with over ten-fold enhanced restriction of the avian IAV strain H5N1 but reduced THOV restriction. Analysis of super-restrictor MxA variants reveals that the identity of residue 561 explains most of MxA's breadth-specificity tradeoff in H5N1 versus THOV restriction. However, rare 'generalist' super-restrictors with enhanced restriction of both viruses allow MxA to overcome the breadth-specificity tradeoff. Finally, we show that a heterozygous combination of two 'specialist' super-restrictors, one against THOV and the other against IAV, enhances restriction against both viruses. Thus, two strategies enable restriction factors such as MxA to increase their restriction of diverse viruses to overcome breadth-specificity tradeoffs that may be pervasive in host-virus conflicts.

Structural characterization and bioactivity profiling of the fungal peptaibiotic tolypin reveal protective effects against influenza viruses.

In a bioprospection for new antivirals, we tested nonribosomally biosynthesized polypeptide antibiotics in MDCK II cells for their actions on influenza A and B viruses (IAV/IBV). Only tolypin, a mixture of closely related 16-residue peptaibiotics from the fungus Tolypocladium inflatum IE 1897, showed promising activity. It was selected for further investigation and structural characterization byultrahigh performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HR-MS/MS) and ultrahigh performance liquid chromatography coupled to in-source collision-induced dissociation tandem mass spectrometry (UHPLC-isCID-HR-MS/MS), revealing 12 partially co-eluting individual peptides that were fully sequenced. Since tolypin-related efrapeptins are potent inhibitors of F1/Fo-ATPase, we screened tolypin for its toxicity against MDCK II cells and larvae of the greater wax moth Galleria mellonella. We found that a nontoxic concentration of tolypin (1 µg/mL) reduced the titer of two IBV strains by 4-5 log values, and that of an H3N2 strain by 1-2 log values, but the H1N1pdm strain was not affected. The higher concentrations of tolypin were cytostatic to MDCK II cells, shifted their metabolism from oxidative phosphorylation to glycolysis, and induced paralysis in G. mellonella, supporting the inhibition of F1/Fo-ATPase as the mode of action. Our results lay the foundations for future work to investigate the interplay between viral replication and cellular energy metabolism, as well as the development of drugs that target host factors.

Immunity and Protective Efficacy of a Plant-Based Tobacco Mosaic Virus-like Nanoparticle Vaccine against Influenza a Virus in Mice.

The rapid production of influenza vaccines is crucial to meet increasing pandemic response demands. Here, we developed plant-made vaccines comprising centralized consensus influenza hemagglutinin (HA-con) proteins (H1 and H3 subtypes) conjugated to a modified plant virus, tobacco mosaic virus (TMV) nanoparticle (TMV-HA-con). We compared immune responses and protective efficacy against historical H1 or H3 influenza A virus infections among TMV-HA-con, HA-con protein combined with AddaVax™ adjuvant, and whole-inactivated virus vaccine (Fluzone®). Immunogenicity studies demonstrated robust IgG, IgM, and IgA responses in the TMV-HA-con and HA-con protein vaccinated groups, with relatively low induction of interferon (IFN)-γ+ T-cell responses across all vaccinated groups. The TMV-HA-con and HA-con protein groups displayed partial protection (100% and 80% survival) with minimal weight loss following challenge with two H1N1 strains. The HA-con protein group exhibited 80% and 100% survival against two H3 strains, whereas the TMV-HA-con groups showed reduced protection (20% survival). The Fluzone® group conferred 20-100% survival against two H1N1 strains and one H3N1 strain, but did not protect against H3N2 infection. Our findings indicate that TMV-HA and HA-con protein vaccines with adjuvant induce protective immune responses against influenza A virus infections. Furthermore, our results underscore the potential of plant-based production using TMV-like nanoparticles for developing influenza A virus candidate vaccines.

Reducing amplification cycles to improve the coverage of influenza A virus genome sequencing in heterosubtypic co-infection

This study delineates the enhancement of a Reverse Transcription Polymerase Chain Reaction (RT-PCR) method for the amplification of the complete genome of the influenza A virus during heterosubtypic co-infection, relying on the amplification of intact gene segments. The precision of the method was assessed using all amplicons, which underwent both capillary electrophoresis and DNA sequencing. Five samples featuring co-infection of Influenza A viruses with H1N1 and H3N2 subtypes were evaluated. The improved strategy successfully amplified all eight segments of H3N2 strains in four samples, and the entire genome of H1N1 strains in three samples.

A Study to Assess the Effectiveness of Structured Teaching Program on Knowledge Regarding Prevention of Swine Flu Among in Rural Area in Indore City

Pigs around the world are susceptible to swine influenza, a respiratory disease brought on by type A influenza viruses, particularly strains H1N1, H1N2, H2N1, H3N1, H3N2, and H2N3. Swine influenza viruses can infect humans and cause mild to severe sickness in people of all ages. Those who come into contact with pigs are particularly at risk. Influenza epidemiology research was previously only done in resource-rich nations. After 30,000 cases of H1N1 illness were recorded from more than 70 countries on June 11, 2009, the World Health Organization proclaimed an H1N1 pandemic. The frequency of swine influenza significantly increased in 2015, reaching a 5-year high. 2015 saw 10,000 instances of swine flu confirmed in India, with 774 fatalities. KEYWORDS : Prevention from Swine flu, Rural area, Structured Teaching Programme

Deciphering avian hematopoietic stem cells by surface marker screening and gene expression profiling

BackgroundAvian species have played a pivotal role in developmental hematopoiesis research, leading to numerous critical discoveries. Avian influenza, particularly the H5N1 strain, poses a significant threat to poultry and has zoonotic potential for humans. Infections often result in abnormal hematologic profiles, highlighting the complex interplay between avian diseases and hematopoiesis. Many avian diseases can suppress immune cells in the bone marrow (BM), impacting immune responses. Studying hematopoietic stem cells (HSCs) in avian BM is crucial for understanding these processes and developing effective vaccines and protection strategies for both avian and human health. MethodsThis study adapted methods from mouse studies to isolate avian HSCs as Lineage-negative (Lin-) cells. These isolated cells were further identified as Lin-Sca1+c-Kit+ (LSK) and were found to be more prevalent than in control groups. RT-PCR analyses were conducted, showing that genes like MEIS1 and TSC1 were upregulated, while SIRT1, FOXO1, and AHR were downregulated in these stem cells. Screening for LSK markers revealed ten unique surface antigens in the Sca1+c-Kit+ cell populations, including highly enriched antigens such as CD178, CD227, and CD184. Additionally, studies on quail HSCs demonstrated that similar labeling techniques were effective in quail BM. ResultsThe research demonstrated that the identification of avian HSC-specific surface antigens provides valuable insights into the pathogenesis of avian influenza and other diseases, enhancing our understanding of how these diseases suppress HSC function. Notably, the upregulation of MEIS1 and TSC1 genes in LSK cells underscores their critical roles in regulating hematopoietic processes. Conversely, the downregulation of SIRT1, FOXO1, and AHR genes provides important clues about their roles in differentiation and immune response mechanisms. DiscussionThe findings of this study deepen our understanding of the effects of avian diseases on the immune system by identifying surface markers specific to avian HSCs. The suppression of HSC function by pathogens such as influenza highlights the importance of understanding these cells in developing targeted vaccines. These results represent a significant step towards improving global health security by mitigating risks associated with avian pathogens.

Understanding the stability and dynamics of influenza a H5N1 polymerase PB2 CAP-Binding domain in complex with natural compounds for antiviral drug discovery

Influenza A virus, particularly the H5N1 strain, poses a significant threat to public health due to its ability to cause severe respiratory illness and its high mortality rate. Traditional antiviral drugs targeting influenza A virus have faced challenges such as drug resistance and limited efficacy. Therefore, new antiviral compounds are needed to be discovered and developed. This study concentrated on examining the stability and behavior of the H5N1 polymerase PB2 CAP-binding domain when interacting with natural compounds, aiming to identify potential candidates for antiviral drug discovery. Through the virtual screening process, four lead compounds, ZINC000096095464, ZINC000044404209, ZINC000001562130, and ZINC000059779788, were selected, and these compounds showed binding energies −9.6, −9.4, −9.3, and −9.2 kcal/mol, respectively. When complexed with PB2, the ligand showed acceptable binding stability due to significant bond formation. However, during the 200ns MD simulation analysis, three (ZINC000096095464, ZINC000044404209, and ZINC000059779788) showed significant stability, which was proven by the trajectory analysis. The Rg-RMSD-based FEL plot showed significant structural stability due to stable conformers. The free-binding energy calculation also validates the stability of these complexes. This study offers valuable insights into the stability and dynamics of the H5N1 polymerase PB2 CAP-binding domain in complexes with natural compounds. These findings highlight the potential of these natural compounds as antiviral agents against the H5N1 influenza virus. Furthermore, this research contributes to the broader field of influenza virus treatment by demonstrating the effectiveness of computational methods in predicting and evaluating the stability and dynamics of potential drug candidates.

Antiviral Activity of Angelica Tenuissima Nakai against Influenza A Virus.

The influenza A virus poses a serious threat to human health and is an important global public health issue. The drugs currently used for treatment are becoming increasingly ineffective against influenza A viruses and require the development of new antiviral drugs. Angelica tenuissima Nakai (ATN), a traditional herbal medicine belonging to the Umbelliferae family, exhibits a broad range of pharmacological activities, including inflammation, headache, and cold symptoms. In the present study, based on target protein identification, functional enrichment analysis, and gene set comparisons, we first suggested that ATN has potential therapeutic effects against influenza A virus infection. Next, methylthiazol tetrazolium (MTT) and sulforhodamine B colorimetric (SRB) assay results revealed that ATN exhibited low cytotoxicity in Madin-Darby canine kidney (MDCK) cells. The antiviral properties of ATN were observed against H1N1 and H3N2 virus strains. Microscopy confirmed the increased survival rate of the host cells. Further time-of-addition experiments revealed that the addition of ATN before virus adsorption showed similar results to the whole period of treatment. The pre- and co-treated groups showed lower levels of viral RNA (M1 protein). The results of this study suggest that ATN exhibits antiviral properties against the influenza A virus. These therapeutic properties of ATN can serve as a theoretical basis for further research on the applicability of ATN in the development of antiviral agents.

Infection of South American coatis (Nasua nasua) with highly pathogenic avian influenza H5N1 virus displaying mammalian adaptive mutations

Deadly outbreaks among poultry, wild birds, and carnivorous mammals by the highly pathogenic H5N1 virus of the clade 2.3.4.4b have been reported in South America. The increasing virus incidence in various mammal species poses a severe zoonotic and pandemic threat. In Uruguay, the clade 2.3.4.4b viruses were first detected in February 2023, affecting wild birds and backyard poultry. Three months after the first reported case in Uruguay, the disease affected a population of 23 coatis (Nasua) in an ecological park. Most animals became infected, likely directly or indirectly from wild birds in the park, and experienced sudden death. Five animals from the colony survived, and four of them developed antibodies. The genomes of the H5N1 strains infecting coatis belonged to the B3.2 genotype of the clade 2.3.4.4b. Genomes from coatis were closely associated with those infecting backyard poultry, but transmission likely occurred through wild birds. Notable, two genomes have a 627K substitution in the RNA polymerase PB2 subunit, a hallmark amino acid linked to mammalian adaptation. Our findings support the ability of the avian influenza virus of the 2.3.4.4b clade to infect and transmit among terrestrial mammals with high pathogenicity and undergo rapid adaptive changes. It also highlights the coatis' ability to develop immunity and naturally clear the infection.

A Novel Application of Virus Like Particles in the Hemagglutination Inhibition Assay.

The hemagglutination inhibition (HI) assay is a traditional laboratory procedure for detection and quantitation of serum antibodies of hemagglutinating viruses containing the hemagglutinin (HA) gene. The current study aimed to investigate the novel use of virus like particles (VLP) as an antigen for the HI assay. VLPs were prepared from a strain of H5N1 using a baculovirus expression system. The VLPs were characterized using the hemagglutination test, Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting, and transmission electron microscopy. The comparative HI assay was performed using three different seed antigens: A/chicken/Mexico/232/94 (H5N2), A/chicken/Egypt/18-H/09(H5N1) and A/goose/Guangdong/1/1996(H5N1). The HI assay of serum antibody titrations using homologous antigens to these vaccinal seeds were compared to the VLP's antigens for the same serum. The HI titers were logically relevant to the similarity between VLP antigens and vaccinal seeds, indicating the VLPs behave similarly to the standard HI assay which uses inactivated whole virus as an antigen. VLPs could be considered as an alternative to the HI assay antigen as they show a relatedness between the similarity with vaccinal seed and serum antibodies. Compared to typical entire H5N1 viral antigen prepared in SPF eggs that require proper inactivation to avoid any public health risk, VLPs prepared in tissue culture, plants or insect cells are a safe, inexpensive and scalable alternative to inactivated whole virus antigen.

Mass vaccination with reassortment-impaired live H9N2 avian influenza vaccine

Avian influenza poses a severe threat to poultry production and global food security, prompting the development of vaccination programs in numerous countries. Modified live virus (MLV) vaccines, with their potential for mass application, offer a distinct advantage over existing options. However, concerns surrounding reversion, recombination, and unintended transmission have hindered the progress of MLV development for avian influenza in poultry. To address these concerns, we engineered reassortment-impaired, non-transmissible, safe, immunogenic, and protective MLVs through the rearrangement of internal gene segments and additional modifications to the surface gene segments HA and NA. The unique peptide marker aspartic acid-arginine-proline-alanine-valine-isoleucine-alanine-asparragine (DRPAVIAN) was incorporated into HA, while NA was modified to encode the chicken interleukin-18 (ckIL18) gene (MLV-H9N2-IL). In vitro, the MLV-H9N2 and MLV-H9N2-IL candidates demonstrated stability and virus titers comparable to the wild-type H9N2 strain. In chickens, the MLV-H9N2 and MLV-H9N2-IL candidates did not transmit via direct contact. Co-infection studies with wild-type virus confirmed that the altered HA and NA segments exhibited fitness disadvantages and did not reassort. Vaccinated chickens showed no clinical signs upon vaccination, all seroconverted, and the inclusion of ckIL18 in the MLV-H9N2-IL vaccine enhanced neutralizing antibody production. A significant decrease in viral loads post-challenge underscored the protective effect of the MLVs. The MLV-H9N2-IL vaccine, administered via drinking water, proved immunogenic in chickens in a dose-dependent manner, generating protective levels of neutralizing antibodies upon aggressive homologous virus challenge. In summary, this study lays the groundwork for safe MLVs against avian influenza suitable for mass vaccination efforts.

Analysis of seasonal H3N2 influenza virus epidemic characteristics and whole genome features in Jining City from 2018 to 2023.

Seasonal H3N2 influenza virus, known for its rapid evolution, poses a serious threat to human health. This study focuses on analyzing the influenza virus trends in Jining City (2018-2023) and understanding the evolving nature of H3N2 strains. Data on influenza-like cases were gathered from Jining City's sentinel hospitals: Jining First People's Hospital and Rencheng Maternal and Child Health Hospital, using the Chinese Influenza Surveillance Information System. Over the period from 2018 to 2023, 7844 throat swab specimens were assessed using real-time fluorescence quantitative PCR for influenza virus nucleic acid detection. For cases positive for seasonal H3N2 influenza virus, virus isolation was followed by whole genome sequencing. Evolutionary trees were built for the eight gene segments, and protein variation analysis was performed. From 2018 to 2023, influenza-like cases in Jining City represented 6.99% (237 299/3 397 247) of outpatient visits, peaking in December and January. Influenza virus was detected in 15.67% (1229/7844) of cases, primarily from December to February. Notably, no cases were found in the 2020-2021 season. Full genome sequencing was conducted on 70 seasonal H3N2 strains, revealing distinct evolutionary branches across seasons. Significant antigenic site variations in the HA protein were noted. No resistance mutations to inhibitors were found, but some strains exhibited mutations in PA, NS1, PA-X, and PB1-F2. Influenza trends in Jining City saw significant shifts in the 2020-2021 and 2022-2023 seasons. Seasonal H3N2 exhibited rapid evolution. Sustained vigilance is imperative for vaccine updates and antiviral selection.

Impact of Pre-Existing Immunity and Age on Antibody Responses to Live Attenuated Influenza Vaccine.

Live attenuated influenza vaccines (LAIV) typically induce a poor hemagglutination inhibition (HI) response, which is the standard correlate of protection for inactivated influenza vaccines. The significance of the HI response is complicated because the LAIV vaccine primarily induces the local mucosal immune system, while the HI assay measures the circulating serum antibody response. However, age and pre-existing immunity have been identified as important factors affecting LAIV immunogenicity. This study aimed to extend our understanding of LAIV-induced immunity, particularly, the impact age and pre-existing immunity have on eliciting functional and neutralising antibody responses in paediatric and adult populations vaccinated with LAIV. Thirty-one children and 26 adults were immunized with the trivalent LAIV during the 2013-2014 influenza season in Norway. Children under 9 years received a second dose of LAIV 28 days after the first dose. Blood samples were collected pre- and post-vaccination. HI, microneutralization (MN) and enzyme-linked lectin assay for neuraminidase (NA) antibodies were measured against the vaccine strains. IgG antibody avidity against hemagglutinin (HA) and NA proteins from the vaccine strains was also assessed. Significant correlations were observed between HI and MN responses to A/California/7/2009 (A/H1N1)pdm09-like strain and B/Massachusetts/2/2012-like strain, suggesting that MN is a potential immunological correlate for LAIV. However, the relationship between recipient age (or priming status) and serological response varied between vaccine strains. There was a notable increase in HI and MN responses in all cohorts except naive children against the H1N1 strain, where most recipients had responses below the protective antibody threshold. NAI responses were generally weak in naive children against all vaccine strains compared with adults or antigen-primed children. Post-vaccination antibody avidity increased only in primed children below nine years of age against the A/H1N1 strain. Overall, our findings indicate that LAIV elicits functional and neutralizing antibody responses in both naive and antigen experienced cohorts, however, the magnitude and kinetics of the response varies between vaccine strains.

Synthesis and Biological Activity of New Hydrazones Based on N-Aminomorpholine.

The data on the synthesis of N-aminomorpholine hydrazones are presented. It is shown that the interaction of N-aminomorpholine with functionally substituted benzaldehydes and 4-pyridinaldehyde in isopropyl alcohol leads to the formation of corresponding hydrazones. The structure of the synthesized compounds was studied by 1H and 13C NMR spectroscopy methods, including the COSY (1H-1H), HMQC (1H-13C) and HMBC (1H-13C) methodologies. The values of chemical shifts, multiplicity, and integral intensity of 1H and 13C signals in one-dimensional NMR spectra were determined. The COSY (1H-1H), HMQC (1H-13C), and HMBC (1H-13C) results revealed homo- and heteronuclear interactions, confirming the structure of the studied compounds. The antiviral, cytotoxic, and antimicrobial activity of some synthesized hydrazones were investigated. It is shown that 2-((morpholinoimino)methyl)benzoic acid has a pronounced viral inhibitory property, comparable in its activity to commercial drugs Tamiflu and Remantadine. A docking study was performed using the influenza virus protein models (1930 Swine H1 Hemagglutinin and Neuraminidase of 1918 H1N1 strain). The potential binding sites that are complementary with 2-((morpholinoimino)methyl)benzoic acid were found.

Age-dependent heterogeneity in the antigenic effects of mutations to influenza hemagglutinin

Human influenza virus evolves to escape neutralization by polyclonal antibodies. However, we have a limited understanding of how the antigenic effects of viral mutations vary across the human population and how this heterogeneity affects virus evolution. Here, we use deep mutational scanning to map how mutations to the hemagglutinin (HA) proteins of two H3N2 strains, A/Hong Kong/45/2019 and A/Perth/16/2009, affect neutralization by serum from individuals of a variety of ages. The effects of HA mutations on serum neutralization differ across age groups in ways that can be partially rationalized in terms of exposure histories. Mutations that were fixed in influenza variants after 2020 cause greater escape from sera from younger individuals compared with adults. Overall, these results demonstrate that influenza faces distinct antigenic selection regimes from different age groups and suggest approaches to understand how this heterogeneous selection shapes viral evolution.