Search Results (257)

The poultry industry is continually seeking efficient, practical strategies to control infectious diseases. Among these new alternatives are essential oils (EOs), naturally occurring compounds with antimicrobial properties. Their effectiveness has been demonstrated in various studies that focus on their broad antiviral properties. The present experiment evaluated the antiviral efficacy of an EOs formulation against the H7N3 subtype of avian influenza virus (AIV) by directly mixing virus and EOs (virus/EOs mixture) through an in vitro model in cultured Madin-Darby canine kidney cells (MDCKs). The experiment used a focus reduction neutralization test (FRNT) to determine the 50% inhibitory concentration (IC₅₀) by virus/EOs mixture, as well as the application of EOs 24 h before infection, through a viral inhibition test using a chicken embryo (CE) in ovo model. The results demonstrated the antiviral activity of the EOs formulation against the H7N3 in vitro model (IC₅₀ values of 20.4 and 38.3 ppm and selective index (SI) values of 9.4 and 5.1) and in ovo model (decreasing hemagglutination titers to 1 HA unit, 10^5.28 embryo infectious dose 50% (EID₅₀) per mL, and viral loads to approximately 10^11.4 copies/mL) when applied in CE, 24 h before viral infection, representing the lowest replication indicators recorded during the experiment. According to the results, the EOs formulation demonstrated antiviral activity against AIV H7N3 both as a virus/EOs mixture and through application in ovo 24 h before infection. Application 24 h before infection in CE showed a significant effect compared with the virus/EOs mixture, demonstrating an antiviral effect in the ovo infection model. This study demonstrates both the virucidal and antiviral capacity of the compounds in the EOs formulation against AIV H7N3 and their efficacy when applied 24 h before infection in the in ovo model. Full article

Galectin-3 (Gal-3) is a histologic marker of pancreatic cancer and a potential therapeutic target. This study aimed to characterize a novel sulfated agarose-derived oligosaccharide (DP9) from marine algae, Gracilaria lemaneiformis, evaluate its Gal-3 inhibitory activity, and investigate its anti-pancreatic cancer mechanisms. Through controlled acid hydrolysis, a series of odd-numbered oligosaccharides (DP3-11) were obtained, in which DP9 showed the strongest Gal-3 inhibition in hemagglutination assays. Structural analysis confirmed DP9’s unique composition including an alternating β (1→4)-D-galactose and α (1→3)-3,6-anhydro-L-galactose backbone, featuring partial 6-O-methylation on β-D-galactose and 6-O-sulfation on 3,6-anhydro-α-L-galactose residues. Molecular docking revealed DP9’s binding to Gal-3’s carbohydrate recognition domain through key hydrogen bonds (His158, Arg162, Lys176, Asn179 and Arg186) and hydrophobic interactions (Pro117, Asn119, Trp181 and Gly235), with the sulfate group enhancing binding affinity. In vitro studies demonstrated DP9’s selective anti-pancreatic cancer activity against BxPC-3 cells, including inhibition of cell proliferation; S-phase cell cycle arrest; induction of apoptosis; and suppression of migration and invasion. Mechanistically, DP9 attenuated the Gal-3/EGFR/AKT/FOXO3 signaling pathway while showing minimal cytotoxicity to normal cells. This study first demonstrated that agarose-derived odd-numbered oligosaccharides (DP9) can serve as effective Gal-3 inhibitors, which proved its potential as a marine oligosaccharide-based therapeutic agent for pancreatic cancer. Full article

The antigenic relationship between Eurasian avian-like H1N1 swine influenza viruses (EA H1N1) and human pandemic 2009 H1N1 viruses (2009/H1N1) remains a critical question for influenza surveillance and vaccine efficacy. This study systematically investigated the antigenic differences between strains A/swine/Tianjin/312/2016 (TJ312, EA H1N1) and A/Guangdong-Maonan/SWL1536/2019 (GD1536, 2009/H1N1). Cross-hemagglutination inhibition (HI) assays revealed a significant antigenic disparity, with a 16-fold reduction in heterologous versus homologous HI titers. Comparative sequence analysis identified 22 amino acid differences across the five major antigenic sites (Sa, Sb, Ca1, Ca2, and Cb) of the HA1 subunit. Using reverse genetics, a panel of mutant viruses was generated. This study revealed that a single histidine (H)-to-asparagine (N) substitution at residue 128 (H3 numbering) in the Sa antigenic site acts as a primary determinant of antigenic variation, sufficient to cause a four-fold change in HI titers and a measurable drift in antigenic distance. Structural modeling via AlphaFold3 and PyMOL software suggests that the H128N mutation may alter the local conformation of the antigenic site. It is plausible that H at position 128 could exert electrostatic repulsion with adjacent amino acids, whereas N might facilitate hydrogen bond formation with neighboring residues. These interactions would potentially lead to structural changes in the antigenic site. Our findings confirm that residue 128 is a critical molecular marker for the antigenic differentiation of EA H1N1 and 2009/H1N1 viruses. The study underscores the necessity of monitoring specific HA mutations that could reduce cross-reactivity and provides valuable insights for refining vaccine strain selection and pandemic preparedness strategies. Full article

Influenza D virus (IDV), belonging to the Orthomyxoviridae family, was first discovered in 2011 in pigs. Surveys in humans and animals have been carried out to decipher IDV ecology. In this seroepidemiological study, we investigated the circulation of IDV lineages across Italy in livestock and wildlife animals. A total of 1038 animal serum samples (from 246 bovines, 249 swine, 98 equines, and 445 wild boars) were tested using hemagglutination inhibition and virus neutralization assays. The results confirm bovines as the primary reservoir for IDV, with high seroprevalence for both D/660 (87%) and D/OK (80%) strains. Swine and equines demonstrated limited exposure, suggesting they are infrequent spillover hosts. Notably, wild boars showed high seroprevalence, especially for the D/660 lineage (80%), indicating their potential role in a wildlife transmission cycle. Continuous surveillance in both livestock and wildlife is essential to monitor the spread and evolution of IDV. Full article

The H9N2 virus has severely harmed the livestock and bird farming industry. Currently, it is mainly prevented through vaccination immunization. However, conventional vaccines often fail to induce durable immune responses and long-lasting immunoprotection. In this research, we used Simvastatin (Sim) and CpG as adjuvants for the H9N2 inactivated vaccine to evaluate the vaccine’s immunogenicity in chickens. We evaluate vaccine immunogenicity through antibody testing, T lymphocyte phenotyping, and RNA-sequencing analysis. The results indicated that the Sim + CpG/H9N2 formulation significantly enhanced specific IgY and hemagglutination inhibition (HI) antibody titers. It also increased the proportions of CD4⁺ T cells and CD8⁺ T cells, promoted immune organ development, and stimulated the formation of germinal centers. RNA-sequencing analysis revealed that Sim + CpG/H9N2 vaccination significantly upregulated immune-related genes, which were enriched in pathways associated with stress response activation, immune cell recruitment, and inflammatory signaling. Overall, these findings demonstrate that Sim + CpG/H9N2 markedly enhances the immunogenicity of the inactivated H9N2 vaccine and provides new insights into the application of vaccine adjuvants for improved immune protection. Full article

Background/Objectives: The continued evolution and cross-species transmission of clade 2.3.4.4b H5Nx highly pathogenic avian influenza (HPAI) viruses underscores the need for broadly protective vaccines in swine, a key intermediary host. This study aimed to evaluate systemic and mucosal immune responses elicited by adenoviral-vectored (Ad) vaccines encoding a centralized consensus hemagglutinin antigen (H5CC) in mice and swine. Methods: We constructed H5CC-based vaccines that were delivered using replication-defective (Ad5 and Ad6) and replication-competent (Ad28 and Ad48) human adenoviral vectors. Using a serotype-switched prime-boost strategy, vaccines were delivered intramuscularly (IM) or intranasally (IN) in mice and swine. We determined humoral, mucosal, and cell-mediated immune responses by hemagglutination inhibition (HI), microneutralization assay (MNA), ELISA, and IFN-γ ELISpot. Protective efficacy was evaluated by lethal H5N1 challenge in mice. Results: All vaccine strategies and routes induced significant levels of anti-H5 immunity. Ad5/Ad6 IM immunization elicited strong systemic IgG and MNA titers and robust T cell responses. IN delivery with Ad5/Ad6 induced superior mucosal IgA levels in lungs and nasal secretion. In swine, Ad5/Ad6 IM conferred the highest MNA titer and T cell responses, while the IN route enhanced mucosal IgA. The Ad28/Ad48 vaccines induced immunity in a similar pattern as compared to the Ad5/Ad6 strategy, but to a slightly lesser degree, in general. The commercial H1/H3 swine influenza vaccine failed to elicit cross-protective immunity. All H5CC vaccinated mice survived lethal H5N1 challenge without weight loss. Conclusions: Adenoviral-vectored H5CC vaccines elicit broad, cross-clade immunity with route-dependent immune profiles. IM vaccination is optimal for systemic and cellular responses, while IN delivery enhances mucosal immunity. These findings support the advancement of adenoviral platforms for influenza control in swine and pandemic preparedness. Full article

Influenza vaccines are the primary strategy to prevent severe influenza disease; however, their efficacy is often suboptimal, particularly in older adults (OAs). LiteVax Adjuvant (LVA), a novel adjuvant containing carbohydrate fatty-acid monosulphate ester (CMS) as the active ingredient, has demonstrated a favourable safety profile and enhanced immunogenicity when combined with a low-dose seasonal influenza vaccine in adults aged 18 to 50 years in a first-in-human phase 1 study. The present study investigates the reactogenicity and immunogenicity of CMS-based adjuvanted seasonal influenza vaccine in OAs, with a comparison to responses in younger adults (YAs). In this phase 1b, double-blind, active-controlled clinical trial, 36 YAs (18–50 years) and 48 OAs (≥60 years) were randomized (1:1:1) to receive either 0.5 mg or 1 mg LVA combined with VaxigripTetra, or VaxigripTetra alone. Solicited adverse events (AEs) were recorded using an electronic diary for 7 days following vaccination. Hemagglutination inhibition (HI) titers against four influenza strains were measured at baseline (pre-vaccination) and at 7-, 28-, and 180-days post-vaccination. All 24 YAs and 31 out of 32 OAs receiving CMS-based adjuvanted vaccines reported pain post-vaccination, compared to 8/12 YAs and 4/16 OAs receiving VaxigripTetra. Systemic AEs were more frequently reported among YAs receiving CMS-based adjuvanted vaccines (22/24) compared to those receiving VaxigripTetra (8/12). In OAs, the number of systemic AEs was similar regardless of CMS-based adjuvant administration. Most AEs were mild to moderate and resolved within 3 days. Both CMS-based adjuvanted formulations elicited increased HI titers at Day 7, peaking at Day 28, with a decline thereafter that remained above baseline at Day 180. In YAs, HI titers were comparable between the CMS-based adjuvanted and non-adjuvanted vaccines across all strains and timepoints. In contrast, CMS-based adjuvanted vaccination in OAs induced higher HI titers at Days 28 and 180 for all influenza strains tested. LVA shows an acceptable safety profile in both age cohorts and enhances humoral immune responses in older adults. The 1 mg dose of LVA was more immunogenic, highlighting its potential utility in this target population. Future research will focus on elucidating the mechanisms underlying the immunostimulatory effect of the CMS-based adjuvant. Full article

Deoxyshikonin (DS) is a derivative of shikonin, the main compound present in Lithospermi radi, the root of Lithospermum erythrorhizon Siebold and Zucc. In this study, we investigated the antiviral effects of DS using Influenza A/PR8/34, which expresses green fluorescent protein (GFP) as well as wild-type PR8/34 H1N1 Influenza A virus (IAV). Fluorescence microscopy and flow cytometry results showed that DS from 1.25 to 5 µM significantly and dose-dependently inhibited PR8-GFP IAV infection. A plaque assay confirmed the inhibitory effect of DS against H1N1 IAV infection. Consistently, immunofluorescence results showed that DS suppresses IAV protein expression. Time-of-drug-addition and hemagglutination inhibition assays revealed that DS exhibits anti-influenza virus efficacy by blocking the viral attachment and penetration into the cells and has a direct virus-eradication effect in the early stages of infection. However, DS did not repress neuraminidase activity. Our findings suggest that DS could be used not only to protect against the early stages of IAV infection, but also to treat influenza virus infections in combination with NA inhibitors. Full article

Background/Objectives: Influenza represents a significant burden on global public health, and vaccination is the most effective strategy to reduce it. The large investment in vaccination programs and the need for adjustments in vaccine serotypes are important reasons for evaluating the influenza vaccine’s efficacy every year. Establishing a relationship between immunogenicity data and efficacy is also crucial for predicting the efficacy of a vaccine during its development. Antibody response measurement is one of the most common methods for evaluating immunogenicity, particularly in vaccines and biologics. The aim of this systematic review was to define a model that relates the immunogenicity of a given vaccine to its efficacy, based on hemagglutination inhibition titer levels. Methods: To achieve this goal, information was gathered from articles linking immunogenicity with the efficacy of the influenza vaccine in the Medline and Scopus databases. Different mathematical models were developed and applied to assess the relationship between HAI titers and the effectiveness of the flu vaccine. This analysis was conducted for the various existing vaccines, for the different influenza virus strains, and for their efficacy in paediatric populations. Results: The r² obtained ranged from 0.2579 to 0.966, which points to the importance of this immunological factor in the efficacy of the influenza vaccine. Conclusions: The efficacy values for titer level 40 confirm the validity of the data provided by Hobson. Full article

Despite the widespread accessibility of vaccines and antivirals, seasonal influenza virus epidemics continue to pose a threat to public health. In this study, we constructed a recombinant replication-deficient simian adenovirus type 25 vector carrying the full-length hemagglutinin (HA) of the H1N1 influenza virus, named rSAd25-H1. Both systemic and mucosal humoral immune responses, as well as the protective efficacy, were assessed in mice immunized via the intramuscular (IM) or intranasal (IN) route. A single-dose IM or IN administration of rSAd25-H1 elicited a robust systemic IgG antibody response, including hemagglutination inhibition antibodies. As expected, only IN immunization was able to induce IgA production in serum and respiratory mucosa. Notably, a single dose of rSAd25-H1 at the highest dose (10¹⁰ viral particles) conferred complete protection against lethal homologous H1N1 challenge in mice despite the route of administration. These findings demonstrate the potential of simian adenovirus type 25-based vectors as a promising candidate for intranasal vaccine development targeting respiratory pathogens. Full article

Avian influenza A viruses (IAVs) pose a persistent threat to the poultry industry, causing substantial economic losses. Although traditional vaccines have helped reduce the disease burden, they typically rely on multivalent antigens, emphasize humoral immunity, and require intensive production. This study aimed to establish a genetically matched host–cell system to evaluate antigen-specific immune responses and identify conserved CD8+ T cell epitopes in avian influenza viruses. To this end, we developed an MHC class I genotype (B21)-matched host (Lohmann VALO SPF chicken) and cell vector (DF-1 cell line) model. DF-1 cells were engineered to express the hemagglutinin (HA) gene of clade 2.3.4.4b H5N1 either transiently or stably, and to stably express the matrix 1 (M1) and nucleoprotein (NP) genes of A/chicken/South Korea/SL20/2020 (H9N2, Y280-lineage). Following prime-boost immunization with HA-expressing DF-1 cells, only live cells induced strong hemagglutination inhibition (HI) and virus-neutralizing (VN) antibody titers in haplotype-matched chickens. Importantly, immunization with DF-1 cells transiently expressing NP induced stronger IFN-γ production than those expressing M1, demonstrating the platform’s potential for differentiating antigen-specific cellular responses. CD8+ T cell epitope mapping by mass spectrometry identified one distinct MHC class I-bound peptide from each of the HA-, M1-, and NP-expressing DF-1 cell lines. Notably, the identified HA epitope was conserved in 97.6% of H5-subtype IAVs, and the NP epitope in 98.5% of pan-subtype IAVs. These findings highlight the platform’s utility for antigen dissection and rational vaccine design. While limited by MHC compatibility, this approach enables identification of naturally presented epitopes and provides insight into conserved, functionally constrained viral targets. Full article

Background: Influenza A viruses (IAV) cause seasonal flu and occasional pandemics. In addition, the potential for the emergence of new strains presents unknown challenges for public health. Face masks and other personal protective equipment (PPE) can act as barriers that prevent the spread of these viruses. Metal ions embedded into PPE have been demonstrated to inactivate respiratory viruses, but the underlying mechanism of inactivation and potential for resistance is presently not well understood. Methods: In this study, we used hemagglutination assays to quantify the effect of zinc ions on IAV sialic acid receptor binding. We varied the zinc concentration, incubation time, incubation temperature, and passaged IAV in the presence of zinc ions to investigate if resistance to zinc ions could evolve. Results: We found that zinc ions impact the ability of IAV particles to hemagglutinate and observed inhibition within 1 min of exposure. Maximum inhibition was achieved within 1 h and sustained for at least 24 h in a concentration-dependent manner. Inhibition was also temperature-dependent, and optimal above room temperature. Serial passaging of IAV in the presence of zinc ions did not result in resistance. Conclusions: e conclude that zinc ions prevent IAV hemagglutination in a concentration and temperature-dependent manner for at least 24 h. Overall, these findings are in line with previous observations indicating that zinc-embedded materials can inactivate the IAV hemagglutinin and SARS-CoV-2 spike proteins, and they support work toward developing robust, passive, self-cleaning antiviral barriers in PPE. Full article

Background: Fowl typhoid (FT), a septicemic infection caused by Salmonella Gallinarum (SG), and H9N2 avian influenza are two economically important diseases that significantly affect the global poultry industry. Methods: We exploited the live attenuated Salmonella Gallinarum (SG) mutant JOL3062 (SG: ∆lon ∆pagL ∆asd) as a delivery system for H9N2 antigens to induce an immunoprotective response against both H9N2 and FT. To enhance immune protection against H9N2, a prokaryotic and eukaryotic dual expression plasmid, pJHL270, was employed. The hemagglutinin (HA) consensus sequence from South Korean avian influenza A virus (AIV) was cloned under the Ptrc promoter for prokaryotic expression, and the B cell epitope of neuraminidase (NA) linked with matrix protein 2 (M2e) was placed for eukaryotic expression. In vitro and in vivo expressions of the H9N2 antigens were validated by qRT-PCR and Western blot, respectively. Results: Oral immunization with JOL3121 induced a significant increase in SG and H9N2-specific serum IgY and cloacal swab IgA antibodies, confirming humoral and mucosal immune responses. Furthermore, FACS analysis showed increased CD4+ and CD8+ T cell populations. On day 28 post-immunization, there was a substantial rise in the hemagglutination inhibition titer in the immunized birds, demonstrating neutralization capabilities of immunization. Both IFN-γ and IL-4 demonstrated a significant increase, indicating a balance of Th1 and Th2 responses. Intranasal challenge with the H9N2 Y280 strain resulted in minimal to no clinical signs with significantly lower lung viral titer in the JOL3121 group. Upon SG wildtype challenge, the immunized birds in the JOL3121 group yielded 20% mortality, while 80% mortality was recorded in the PBS control group. Additionally, bacterial load in the spleen and liver was significantly lower in the immunized birds. Conclusions: The current vaccine model, designed with a host-specific pathogen, SG, delivers a robust immune boost that could enhance dual protection against FT and H9N2 infection, both being significant diseases in poultry, as well as ensure public health. Full article

The aim of this study was to determine the level of anti-hemagglutinin antibodies using the hemagglutination inhibition test (HAI) in the blood sera of patients collected during the 2023/2024 epidemic season in Poland. This data is valuable for assessing the level of population immunity to influenza viruses circulating in Poland during this epidemic season. The study material consisted of serum samples collected across the country and divided into seven age groups. The test results confirmed the presence of anti-hemagglutinin antibodies for the antigens included in the quadrivalent influenza vaccine recommended by the World Health Organization (WHO) for the 2023/2024 epidemic season: A/Victoria/4897/2022 (H1N1)pdm09, A/Darwin/9/2021 (H3N2), B/Austria/1359417/2021 (B/Victoria lineage) and B/Phuket/3073/2013 (B/Yamagata lineage). The highest values of the geometric mean (GMT = 121.0 [95% CI: 108.5–134.9]) and protective factor (70 [95% CI: 67–74]%) were recorded for the A/H3N2/influenza virus antigen. In Poland, the vaccination rate of the general population in the discussed season was only 5.52%. The obtained results can therefore be interpreted as a response of the immune system, consisting of the production of anti-hemagglutinin antibodies in patients who had previously had an infection caused by the influenza virus. Full article

Background: Rabbit hemorrhagic disease (RHD) is an acute, hemorrhagic and highly lethal infectious disease caused by rabbit hemorrhagic disease virus (RHDV), which causes huge economic losses to the rabbit breeding industry. Moreover, there is limited cross-protection between the two different serotypes of classic RHDV (GI.1) and RHDV2 (GI.2). The shortcomings of traditional inactivated vaccines have led to the development of novel subunit vaccines that can protect against both strains, and the VP60 capsid protein is the ideal antigenic protein. This study focused on developing a bivalent RHDV vaccine that can prevent infection with both GI.1 and GI.2 strains. Methodology: Baculovirus vectors containing classic RHDV and RHDV2 VP60 were co-transfected with linearized baculovirus into sf9 cells and transferred to baculovirus via homologous recombination of the VP60 gene. Infected sf9 cells were lysed, and after purification via Ni-NTA chromatography, VLPs were observed using transmission electron microscopy (TEM). In order to evaluate the immunogenicity of the chimeric RHDV VLP vaccine in rabbits, the RHDV VP60-specific antibody, IL-4, IFN-γ and neutralizing antibody titers were analyzed in serum using ELISA and HI. Results: The recombinant baculovirus system successfully expressed chimeric RHDV VLPs with a diameter of 32–40 nm. After immunization, it could produce specific antibodies, IL-4 and IFN-γ. Following the second immunization, neutralizing antibodies, determined using hemagglutination inhibition (HI) assays, were elicited. Conclusions: These data show that the chimeric RHDV VLP bivalent vaccine for immunized New Zealand rabbits can induce humoral immunity and cellular immunity in vivo, and the immunization effect of the high-dose group is similar to that of the current commercial vaccine. Full article