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Emerging severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants have raised concerns about the efficacy of vaccines. The present study aimed to compare the potential of Delta and Omicron variant-specific mRNA vaccines in inducing immune responses. B cell and T cell epitopes and population coverage of spike (S) glycoprotein of the variants were predicted using the Immune Epitope Database. The molecular docking was carried out between the protein and different toll-like receptors, as well as the receptor-binding domain (RBD) protein and angiotensin-converting-enzyme 2 (ACE2) cellular receptor using ClusPro. The molecular simulation was done for each docked RBD-ACE2 using YASARA. The mRNA secondary structure was predicted through the RNAfold. The simulation of immune responses to the mRNA vaccine construct was performed using C-ImmSim. Apart from a few positions, no significant difference was observed in the prediction of S protein B cell and T cell epitopes of these two variants. The lower amounts of Median consensus percentile in the Delta variant in similar positions signify its stronger affinity to major histocompatibility complex (MHC) II binding alleles. Docking of Delta S protein with TLR3, TLR4, and TLR7 and also its RBD with ACE2 showed striking interactions with the lower binding energy than Omicron. In the immune simulation, elevated levels of cytotoxic T lymphocytes, helper T lymphocytes, and memory cells in both the active and resting states and the main regulators of the immune system suggested the capacity of mRNA constructs to elicit robust immune responses against SARS-CoV-2 variants. Considering slight differences in the binding affinity to MHC II binding alleles, activation of TLRs, mRNA secondary structure stability, and concentration of immunoglobulins and cytokines, the Delta variant is suggested for the mRNA vaccine construction. Further studies are being done to prove the efficiency of the design construct. [ABSTRACT FROM AUTHOR]

The effectiveness of inactivated H9N2 influenza vaccines is doubtful due to changes in antigenic regions of the virus hemagglutinin (HA) protein. One strategy for the development of the efficacious vaccine is the use of nanoparticles that display more immunogenic regions of the influenza virus. In this study, chitosan (CS)-based nanoparticles were developed as a delivery system for intranasal immunization using recombinant H9N2 virus HA1 and nucleoprotein (NP), for the induction of humoral and cellular responses. CS-HA1 and CS-NP nanoparticles were prepared by the ionic gelation method and characterized for their physicochemical properties and shape. The immunogenicity and the protective efficacy were evaluated by measuring antibody titers, T cell proliferation response, CD4+/CD8+ ratio, and quantitative real-time RT-PCR following intranasal administration of the prepared nanoparticles alone or in combination in chickens compared to an inactivated H9N2 vaccine. The average size, surface charge, and spherical structure of the synthesized nanoparticles showed high quality. Serologic analysis revealed that the immunization of inactivated vaccine groups resulted in strong influenza antibodies, which were significantly (p < 0.05) higher compared to the other groups. The vaccinated chickens with CS-HA1+CS-NP developed higher specific anti-influenza antibodies than in those vaccinated with each of rHA1 and rNP. Administration of a combination of the protein-based nanoparticles has stimulated the activation of both CD4+ and CD8+T cells and induced a significantly higher T cell proliferation. The viral shedding was significantly lower in CS-HA1+CS-NP and inactivated vaccine groups compared with other challenged groups. The data demonstrate the potential of CS-HA1+CS-NP nanoparticles for eliciting specific influenza antibodies and conferring protection in chickens. [ABSTRACT FROM AUTHOR]

Utilizing subunit vaccines is one of the strategies to address influenza infection. Recent innovations have focused on high doses of vaccine antigens and immune enhancers or adjuvant to induce more robust and long-lasting immune responses. Here, an effect of the B cell-activating factor receptor (BAFF-R) to increase the magnitude and durability of immune responses of the recombinant HA1 (rHA1) protein against the H1N1 influenza virus was studied. The HA1 protein and the effector domain of BAFF-R were expressed in the pET-28a (+) vector. Eight-week-old BALB/c mice were equally grouped into five groups (n=20). The 15 and 25 μg/μL of rHA1 were mixed with 2 μg/μL of rBAFF-R and injected three times for vaccinated groups. Three control groups were received normal saline and two concentrations of rHA1. The ability of rBAFF-R in eliciting HA-specific antibody response and stimulating T lymphocyte proliferation to induce the cell-mediated immunity was assayed. Induction of protection was evaluated following the challenge with PR8 strain. Analysis of immune responses showed that the co-administration of rBAFF-R with rHA1 boosted HI responses to the antigen in mice, whilst it was not able to promote the T cell proliferation responses against influenza. Compared to rHA1alone, the rBAFF-R/rHA1 generated efficient protection for the animals. There were no significant differences in eliciting the immune responses in mice immunized with the lower dose of rHA1 than that with the higher dose. The data indicate the rBAFF-R can enhance the primary and memory immune responses to protect against influenza infection. [ABSTRACT FROM AUTHOR]

Introduction: The virulent Newcastle disease virus (NDV) strains cause an economically important infectious disease in poultry. The common vaccination program with genotype II NDV strains is routinely practiced to provide a better protection level against Newcastle disease (ND). Nevertheless, the emergence of new antigenic and genetic variants within the circulating NDVs raises the importance of improved control strategies. The genotype VII NDV is associated with many of the most recent outbreaks of the disease worldwide. Methods: We evaluated the impacts of genetic divergence between the genotypes II and VII on the immunity against NDV to choose a suitable vaccine virus candidate by focusing on the F and HN proteins. Comparative bioinformatics analyses based on B- and T-cell epitopes binding affinity, protein secondary structure and physicochemical properties predictions were applied for genotypes II and VII. Results: Although the results showed more differences in HN protein than F protein, there was no major difference between the predicted antigenicity values, epitope regions, affinity binding to MHC-I and MHC-II, secondary structures, surface accessibility, and stability of these immunogens between genotypes II and VII. Conclusion: The results suggest that genotype II-based live vaccines can induce immune responses against NDV; however, an inactivated vaccine formulated by genotype VII should be considered in combination with the traditional live vaccine to provide better protection in controlling programs against ND. [ABSTRACT FROM AUTHOR]

Background: Non-ionic surfactant, Tween-80 (TW80) is commonly used for drug delivery due to its effect on the cell membrane permeation. The change in permeability can also increase viral infectivity in cells. This study was undertaken to improve upon Newcastle disease virus (NDV) titer cultivated with embryonic chicken eggs. Methods: The toxicity of TW80 was investigated against chicken embryos at varying concentrations, and changes in the morphology and weights of the heart, liver, and spleen of 4-day old chicken embryos were analyzed. Also, the effect of non-toxic concentrations of TW80 was examined on the infectivity of NDV. The virus was titrated in the allantoic fluid, using a 50% embryo infectious dose (EID50). Results: At high concentrations of TW80, hemorrhage-induced mortality was observed in embryos at the early stages of incubation. The embryos' viability was not affected at low TW80 concentrations, indicating that its toxicity to the chicken embryos was dose-dependent. The infectivity titer of NDV was increased in the presence of TW80 compared to those inoculated with NDV only. Conclusion: The data suggest that TW80 is toxic to chicken embryos at high concentrations, but it enhances cell membrane permeability for NDV particles at low concentrations without affecting the embryos' viability. [ABSTRACT FROM AUTHOR]

The infectious bursal disease virus (IBDV) causes an acute and highly contagious immunosuppressive response in young chickens by targeting B lymphocytes in immune organs. Changes in regulatory T-cell ratio and apoptosis have been demonstrated during IBDV infection in these cells. The possible change in CD19 expression as the precursor of B cells after IBDV replication was detected in this study. Raji cells were infected with an IBDV isolate at MOIs of 1.0 and 3.0. The viral kinetics were determined using the characteristic virus-induced CPE, cell viability, and infectious titer. Induction of apoptosis and also changes in the CD19 expression within the virus infection were assessed by flow cytometry. The Raji cells were found to be susceptible to IBDV infection by producing marked CPEs dependent on MOI. The infectivity titers were determined in intra- and extracellular samples at the defined hours. The kinetics of early IBDV replication in Raji cells were nearly identical for both MOIs, but a significant difference in the infectivity titer was observed at 48 hpi. The quick apoptotic events were observed to be significantly higher in MOI 3.0, which was correlated with the lower virus titer. A significant CD19 expression change in the IBDV-infected Raji cells was revealed. The results suggested that Raji cells mimic the IBDV replication in lymphoid organs and the virus replication is related to CD19 expression frequencies in the lymphoid cells. • IBDV targets the medullary bursa in the avian host with a preference for B cells. • Raji cell line has the potential for IBDV replication and support higher viral growth titers. • Changes in Bregs expression be suitable in monitoring IBDV replication in a B cell-originated cell line. • The change in the level of CD19 marker is closely associated with IBDV infection. [ABSTRACT FROM AUTHOR]

Despite the robust induction of humoral immune responses, a limitation of many adjuvants is their weak stimulation of cellular immunity. The development of synthetic gene-encoding adjuvants for simultaneous induction of both humoral and cell-mediated immune responses is under study. In this study, we examined the impact of toll/interleukin-1 receptor (TIR) domain of toll-like receptor 7 (TLR7) as molecular adjuvants on potency of inactivated infectious bursal disease (IBD) vaccines. A total of 60 specific pathogen-free week-old chicks were randomized grouped to receive either TIR-TLR7-adjuvanted IBD-inactivated vaccine or inactivated IBD antigen along with an unvaccinated control. Serum antibody titers were measured to estimate the humoral immunity, as well as lymphocyte proliferation activity for cellular immune responses. The protection was estimated after challenge with a very virulent IBD virus (IBDV) strain at 4 weeks postvaccination. The results indicated that one dose of IBD/TIR-TLR7 vaccine induced specific antibody responses, whereas a lower response after administration of inactivated IBD antigen was observed. The stimulation of splenocytes results indicated that the TIR-TLR7 adjuvanted IBD vaccine is capable of modulating cell-mediated immune response in treated chickens. A full protection against IBDV infection was achieved by injection of one dose IBD/TIR-TLR7 vaccine in the challenge trial. This study demonstrated that codelivery of TIR-TLR7 with inactivated IBD antigen resulted in simultaneous enhancing immune responses against IBD. [ABSTRACT FROM AUTHOR]

Background: H9N2 avian influenza viruses have the potential to become the next human pandemic threat and next generation vaccine technologies are needed. Current studies introduce nanoparticles as a proper vaccine delivery vehicle for induction of protective immunity. In this study, the efficacy of chitosan nanoparticle-based H9N2 influenza vaccine with and without hemokinin-1 (HK-1) as a molecular adjuvant to induce protective immunity against the virus was examined. Methods: The H9N2 antigen was prepared in MDCK cells and inactivated with formalin. The inactivated antigen alone and in combination with HK-1 was encapsulated into chitosan nanoparticles. Groups of BALB/c mice received chitosan nanoparticle-based H9N2 antigen alone or in combination with HK-1 in a prime/boost platform via eye drop method. To evaluate the efficacy of the adjuvanted-nanovaccine candidate, systemic antibody responses were compared among the groups of animals. Results: Serological analysis indicated that mice receiving the HK-1/H9N2 nanoparticles formulation induced higher antibody titers that were sustained until the end of experiment. However, in the immunized mice, influenza specific antibody titers were comparable to that in the animals which were immunized either with inactivated antigen alone or the H9N2 nanoparticles without HK-1 adjuvant. Conclusion: The data demonstrate the synergy between HK-1 as an adjuvant and chitosan nanoparticles as a delivery antigen/adjuvant carrier in the improvement of influenza immune responses. [ABSTRACT FROM AUTHOR]

Currently, a variety of immunostimulatory molecules are used as adjuvants in combination with poor immunogenic recombinant infectious bursal disease virus (IBDV) vaccine antigen. TIR domain of Toll-like receptors (TLRs) triggers the interleukin-1 (IL-1) signaling cascade which plays a critical role in immune responses against infectious agents. For this study, the bacmid DNA pBac-VP2 of a field isolate was generated and transfected to Sf9 insect cells to produce recombinant VP2 (rVP2). In addition, based on in silico analysis, the cDNA encoding the conserved TIR domain of TLR7 (TIR-TLR7) contain the IL-1 receptor was synthesized and used as an adjuvant. We further evaluated the ability of rVP2/TIR-TLR7 vaccine candidate to induce specific immune responses in specific pathogen-free (SPF) chickens and compared the efficacy by challenging with the virulent IBDV. The results indicate that rVP2/TIR-TLR7-adjuvanted vaccine elicited humoral immune responses and protected chickens against IBDV infection. Higher levels of neutralizing IBDV antibody titers were observed in chickens intramuscularly immunized with rVP2/TIR-TLR7 than those injected with rVP2 alone. The antibody titers were higher in chickens which received booster injection. Furthermore, chickens immunized with rVP2/TIR-TLR7 in the prime and boost groups had significant protection against a virus challenge. The survival rate was 70 and 90% after the primary and booster rVP2/TIR-TLR7 vaccinations, respectively, and indicated that they were protected from virus challenge. Despite the unvaccinated control group, the immunized chickens with rVP2/TIR-TLR7 did not show any clinical signs and histopathological changes of the bursa. Our results demonstrate that TIR-TLR7 is a potential vaccine adjuvant and can induce antigen-specific immune responses induced by rVP2 for protection against IBDV infection. [ABSTRACT FROM AUTHOR]

Sambucus nigra (elder) are broadly used species to treat microbial infections. The potential antiviral activity and mechanism action of elder fruit (EF) in human epithelium cell (A549) cultures infected with H9N2 influenza virus were determined. The effect of various concentrations of EF on influenza virus replication was examined by using virus titration, quantitative real time RT-PCR, fusion and lipid raft assays following two treatment procedures: A) pre-treated H9N2 virus with each concentration of EF extract and transfection of A549 cell cultures, and B) each concentrations of EF was added to H9N2 virus infected-cell cultures following virus adsorption. In both treatments with lower doses of EF increased viral titer as well as synthesized viral nucleoprotein as indicating the herb had no inhibitory effects on virus replication. In (B) trial with higher doses, 40 and 80 µg/mL of EF, a significant decrease in virus titer and viral protein synthesis were shown in EF treated cells indicating the herb affect either entry of viruses or inhibition virus particle release. The results suggest that EF treatment of the influenza virus infected-human epithelial cells may involve in lipid raft association which function as platform for formation of viral membrane fusion and budding. Differencesin treatment time and dose of EF extract in infected cells with influenza virus have a marked effect on the efficacy of the herb. [ABSTRACT FROM AUTHOR]

Infectious laryngotracheitis virus (ILTV) infection causes economic losses in the poultry industry. Outbreaks of the infection in commercial poultry are controlled by using attenuated live vaccines. The genomic and antigenic characteristics between virulent and vaccine strains of ILTV are very similar, thus the differential diagnosis of ILTV strains is targeted in controlling programs. Here, the chicken embryonic neural stem (cENS) cell serves as a host model to study virulence characteristics of ILTVs. The susceptibility of cENS cells to different ILTV strains infection was investigated by analyzing the impact of infection on cell death, virus latency, and determining the host cell responses. We found that cENS cells are highly susceptible to vaccine strain ILTV infection. Upon infection, the strain showed faster replication kinetics in cell culture and marked cytopathic effects with affecting the expression of cellular neuropeptide Y (NPY). Virulent strain was able to enter cENS cells, but no infectious virus was produced at third passage. The establishment of latency state was confirmed by molecular detection of viral ICP4 gene and virus reactivation assay. In contrast to vaccine strain, transcription level of cellular NPY was also upregulated significantly following virulent strain infection. The difference expression pattern of NPY in ILTV strains-infected cells is most closely with the presence of CPE in culture. The neural stem cell system may provide the most relevant tool for differential diagnosis of ILTV strains. [ABSTRACT FROM AUTHOR]

Immunization with DNA vaccines as a novel alternative to conventional vaccination strategy requires adjuvant for improving vaccine efficacy. The conserved immunogenic HA2 subunit, which harbors neutralizing epitopes is a promising vaccine candidate against influenza viruses. In this study, for the first time we explore the idea of using host interferon inducible Mx protein to increase the immunogenicity of HA2 H9N2 influenza DNA vaccine. The potency and safety of the Mx adjuvanted-HA2 vaccine was evaluated in BALB/c mice by different prime-boost strategies. To assess the effect of the vaccination on the virus clearance rate, mice were challenged with homologous influenza virus. Administration of the adjuvanted vaccine and boosting with the same regimen could effectively enhance both humoral and cellular immune responses in treated mice. These data demonstrated that Mx as host defense peptide can be potentiated for improving influenza vaccine efficacy. [ABSTRACT FROM AUTHOR]

A cDNA clone for factor 10 (FX) isolated from chicken embryo inserted into the mammalian cell expression vector pCDNA3.1 was transfected into the baby hamster kidney (BHK-21) cell line. The generated BHK-21 cells with inducible expression of FX were used to investigate the efficacy of the serine transmembrane protease to proteolytic activation of influenza virus hemagglutinin (HA) with monobasic cleavage site. Data showed that the BHK-21/FX stably expressed FX after ten serial passages. The cells could proteolytically cleave the HA of low pathogenic avian influenza virus at multiplicity of infection 0.01. Growth kinetics of the virus on BHK-21/FX, BHK-21, and MDCK cells were evaluated by titrations of virus particles in each culture supernatant. Efficient multicycle viral replication was markedly detected in the cell at subsequent passages. Virus titration demonstrated that BHK-21/FX cell supported high-titer growth of the virus in which the viral titer is comparable to the virus grown in BHK-21 or MDCK cells with TPCK-trypsin. The results indicate potential application for the BHK-21/FX in influenza virus replication procedure and related studies. [ABSTRACT FROM AUTHOR]

Non-ionic surfactants have the ability to alter the cell membrane's permeability for enhancing virus replication. The impact of non-ionic surfactant Tween 80 (TW80) on the infectivity of infectious bursal disease virus (IBDV) was studied in BCL1 cells. The toxicity of different concentrations of TW80 for BCL1 cells was determined for five-time passages. The confluent monolayer of BCL1 was infected by IBDV and subsequently passaged. The adaptation was confirmed by virus titration and RT-PCR assay. Replication kinetics of the cell-adapted IBDV was evaluated in pre-treatment and simultaneous treatment with TW80 at 0.01% concentration. The IBDV infectivity patterns were determined by virus titration, FRAP assay, and transmission electron microscopy. Sequence analysis, RNA secondary structure, and potential N-glycosylation site were conducted for IBDV VP2. Despite the similar cytopathic effects found in both TW80-treated cells and similar ROS levels, the IBDV titer was higher in TW80 pre-treated cells compared to the simultaneous treatment one. Such an increase in IBDV titer did not associate with changes in the VP2 sequence and RNA secondary structure. The possible antioxidant capacity of TW80 can attenuate the ROS damage and improve the cell viability, thereby improving IBDV infectivity. • Infectious bursal disease virus isolate adapts to BCL1 cells following five subsequent passages. • The low concentration of non-ionic surfactant Tween 80 supports IBDV replication to high titers. • A high correlation estimates between the antioxidant activity and the replication of virus. • A synonymous substitution at 1019 nucleotide of VP2 detects as a silent mutation. [ABSTRACT FROM AUTHOR]

Background: In the last decade due to emerge and remerge of influenza viruses, quality improvement of vaccines to increase immune responses in target populations have been more necessary. The potential of biologic adjuvant to stimulate and induce immune system is the basis of modern researches in prevention and controlling program of infectious diseases. In this study, the effect of the coding sequence of cellular Myxovirus resistance (Mx) protein as a biological adjuvant for inducing humoral immune response against influenza virus was investigated. Methods: The experimental study was performed on Balb/c mice in Razi Vaccine and Serum Research Institute from June to November 2014. Three conserved motifs of Mx were selected following sequence alignment between human, mouse and bird species. Potential of the motifs for stimulation immune responses against influenza virus were evaluated using in silico analysis. Based on the immune informatics data Mx1 sequence was the best immune inducer and cloned into pcDNA3.1 vector. Then formulated with inactivated H9N2 influenza antigen as adjuvant and injected to mice groups. The sera of vaccinated mice were collected prior to priming and boosting injections and also at defined weeks and analyzed with serological assays. Histopathological examination was done for evaluation of the vaccine and adjuvant safety. Results: The mean weight of the Balb/c mice in all control and treatment groups was similar and ranged from 21 to 37 gr (P= 0.05). The difference in increasing antibody titers against influenza virus in immunized mice who received Mx1-adjuvanted vaccine especially in second boosting was significant (P= 0.01) compared to the vaccine alone group. More than 78% of the immunized mice receiving two-time boosting have the mean antibody titer of >6 (Log2) which was higher (P= 0.001) comparing to the mice with one booster injection. Conclusion: These data revealed that Mx1 as biological adjuvant was able to increase antibody titer and induction memory immune responses against influenza immunization without causing any side effects. [ABSTRACT FROM AUTHOR]

The full-length non-structural (NS) gene of seven H9N2 isolates (2008-2012) was amplified and genetically analyzed. The NS gene of these isolates belongs to the Y439 sublineage and with an average of 96.4 % identity clustered into two subgroups largely based on their time of isolation. The Ka/Ks ratio was calculated at 0.38 for subgroup 1 and 0.42 for subgroup 2 indicates that purifying selection dominates the evolution of the NS H9 in Iran. The third position of codons values, ranging from 0.371 to 0.392, confirms that synonymous codon usage in NS of the H9N2 viruses was less biased. To investigate the evolution of the NS gene of H9N2 viruses isolated from Asia, phylogenetic analysis was conducted. The results showed that Y439 sublineage with various clusters circulated in Korea, the Middle East, and Pakistan, whereas G1 sublineage existed in China. Homology analysis showed that the NS gene of Korea and Israel isolates grouped into distinct clusters, while most of Iranian isolates were closely related to the Pakistan viruses. Prediction of RNA pseudoknot within NS1 gene using RNA folding path showed eight patterns with different free energy levels. Estimation of free energies suggests destabilization of the pseudoknot and changes in RNA secondary structure may be subject to evolution of NS gene in China. [ABSTRACT FROM AUTHOR]

To understand human response to avian H9N2 influenza, we investigated the effects of the viral infection on A549, HepG2, and HeLa cells at low and high MOIs. To identify virus-host interplay, expression of Mx and NP genes was measured in the cells supernatants. Cell viability and apoptosis were evaluated by MTT assay, DNA fragmentation, and florescent staining. The virus titration and NP gene transcript levels indicate lower susceptibility of HeLa cell to H9N2 replication than other cells. Although H9N2 did produce a faster CPE in HepG2, high dose of the virus induced apoptosis within early stage of A549 infection. The DNA laddering was enhanced in the cell correlated with increase in virus transcripts. The undetectable to different regulation levels of Mx gene were observed in response to H9N2 infection suggesting that an insufficient antiviral defense in the noncompetent-IFN HepG2 cell promotes efficient viral replication. These results showed that the permissivity of HepG2 for H9N2 is comparable with A549; however, liver cells are not target tissue respond to the infection. These data revealed that the H9N2 virus induced apoptosis signaling via mitochondrial pathway in human alveolar epithelial cells, indicating that the induction may be associated with a dose-dependent manner. [ABSTRACT FROM AUTHOR]

Abstract: The full length hemagglutinin (HA) genes of 287 H9N2 AI strains isolated from chickens in Asia during the period 1994–2009 were genetically analyzed. Phylogenetic analysis showed that G1-like viruses circulated in the Middle East and Indian sub-continent countries, whereas other sublineages existed in Far East countries. It also revealed G1-like viruses with an average 96.7% identity clustered into two subgroups largely based on their time of isolation. The Ka/Ks ratio was calculated 0.34 for subgroup 1 and 0.57 for subgroup 2 indicates purifying/stabilizing selection, but despite this there is evidence of localized positive selection when comparing the subgroups 1 and 2 protein sequences. Five sites in HA H9N2 viruses had a posterior probability >0.5 using the Bayesian method, indicating these sites were under positive selection. These sites were found to be associated with the globular head region of HA. To identify sites under positive selection; amino acid substitution classified depends on their radicalism and neutrality. The results indicate that, although most positions in HAs were under purifying selection and can be eliminated, a few positions located in the antigenic regions and receptor binding sites were subject to positive selection. [Copyright &y& Elsevier]

Abstract: A recombinant antigen-based single serum dilution ELISA was developed for simultaneous detection and subtyping of influenza viruses. Recombinant baculovirus encoding the hemagglutinin (HA1 subunit) of H9N2 virus was generated. To evaluate the rHA1-ELISA, microplates were coated with purified HA1 protein and tested with reference control sera. Subsequently, 92 field sera collected from chickens suspected to be infected with H9N2 AIV were employed to test the efficacy of the rHA1-ELISA. The sera were tested simultaneously by HI and a commercial AIV ELISA kit. The rHA1-ELISA appeared to be highly specific and sensitive for direct detection of H9N2 antibodies in serum samples. [ABSTRACT FROM AUTHOR]

Abstract: Chickens fed 200ppb aflatoxin from 10 days of age were evaluated for their immune response to a modified live infectious laryngotracheitis vaccine. Vaccination was administered at age 4 and 12 weeks. Antibody titers to the vaccine were reduced in chickens given dietary aflatoxin. After 7 weeks, aflatoxin feeding was continued for one month in a treated group and was withdrawn in another. Serology indicated significant differences between the two treated groups relative to whether aflatoxin was fed or not. Significant reduction in body weights, antibody titers and elevated SGOT and SGPT levels were found in chickens treated with aflatoxin. The impact of aflatoxin on reduced body weight, decreased SGOT and SGPT levels and lower antibody titers was shown to be significant in the treated group fed on a ration of aflatoxin until throughout the experiment. [Copyright &y& Elsevier]

Purpose: The direct transmission of avian influenza viruses to human and increasing drug resisted strains posing new threats for public health. Therefore, development of efficient vaccines is needed to generate protective and persistent immunity to the viruses. Methods: Three motifs of Mx protein sequence in human, mouse and poultry located in interferon induced (GTP ase) domain were candidate as biologic adjuvant for enhancing the immune responses against influenza virus. Chimera proteins composed with the conserved HA2 subunit of influenza virus and the Mx motifs named HA2/Mx were modeled and evaluated by in silico analysis includes bioinformatics algorithms in order to explore biological characteristics of these peptides. Results: Amongst the predicted models, HA2/Mx1 peptide showed the better results following protein structures prediction, antigenic epitopes determination and model quality evaluation. Comparative homology modeling was performed with Swiss Model and the model was validated using ProSA. Epitope predictions revealed the construct could induce both B and T cell epitopes that expect a high immune response. Conclusion: Taken together, these data indicate that the HA2/Mx1 chimera peptide can be potentiated for developing an adjuvant-fused influenza vaccine capable of stimulating effective immune response. [ABSTRACT FROM AUTHOR]

Application of molecular biology techniques to the production of new vaccines against different strains of the Newcastle disease virus (NDV) has been the subject of recent research reports. Development of improved techniques for genome sequencing has led to the recognition of protective mechanisms and the identification of possible candidate antigens. Such procedures could generate meaningful results regarding the virulence determinants of NDV. This study proposed an in silico approach by assembling potential and conserved epitopic regions of hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins of NDV to induce multiepitopic responses against the virus. Epitope predictions showed that the hypothetical synthetic construct could induce immature B and T cell epitopes that expect a high immune response because of their location in four distinct parts of the construct, namely the head, stalk and the heptad repeated regions known as the HRA and HRB domains. Most regions of the chimeric construct were found to have high antigenic propensity and surface accessibility, which further confirmed the strategy for selection of precise continuous and discontinuous epitopes of HN and F antigens. Thermodynamic folding of mRNA structures revealed correct folding of the RNA construct, indicating good stability of the mRNA to increase the efficiency of translation in the target host. The three-dimensional structure of the native HN-F chimeric protein was successfully generated and validated as a proper model which may define reliability, structural quality and conformation. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the potential effect of flagellin as adjuvant in Newcastle disease virus (NDV) vaccine on the cellular and humoral immunity in chickens. Fifty-six specific pathogen-free chickens were assigned to seven groups of eight chickens and immunized twice with a two-week interval, intramuscularly. Group 1, received phosphate buffered saline as control (C), groups 2, 3, 4, 5, 6 and 7 were immunized with inactivated NDV [Ag], Ag + full FliC protein [AgF], Ag + truncated Flic protein [AgT], Ag + native Flic protein [AgN], commercial NDV vaccine [Vac] and Vac + N [VacN], respectively. After 45 days, spleen and bursa of Fabricius samples were collected and analyzed by flow cytometry and responses in control/vaccinated chickens were studied by immunophenotyping. Humoral response was also, evaluated by ELISA during the experiment. Results showed that immunized chickens with Ag + flagellin proteins had significantly higher frequency of circulating CD3+, CD4+ and CD8+ T cells in bursa of Fabricius in AgF, AgT and AgN, respectively, compared with other groups. Similar results were observed for spleen; however, the highest frequency of circulating CD3+, CD4+ and CD8+ T cells belonged to AgT and AgF, respectively. ELISA results showed that all flagellin-adjuvanted groups had higher antibody titers than other groups with the highest antibody response in VacN. It can be concluded that flagellin may induce both humoral and cellular immune responses against ND and is suggested for use as an efficient adjuvant. • Flagellin-adjuvanted groups had higher frequency of CD4 and CD8 T cells. • All flagellin-adjuvanted groups had higher antibody titers than other groups. • Native flagellin enhanced antibody response in commercial vaccine. [ABSTRACT FROM AUTHOR]

• The most IL-6 and TNF-α gene expression was observed in full flagellin adjuvanted group. • The recombinant full flagellin adjuvanted group showed the highest cellular activity. • The highest HI titer was observed in commercial vaccine and recombinant flagellin adjuvanted groups. The present study was designed to investigate the potential application of native (N) and recombinant (truncated modified [tmFliC] and full-length [flFliC]) flagellin proteins along with inactivated Newcastle disease virus (NDV). Fifty six SPF chickens were immunized twice with PBS (control), inactivated NDV (Ag), inactivated NDV/flFliC (AgF), inactivated NDV/tmFliC (AgT), inactivated NDV/N (AgN), commercial vaccine containing Montanide (Vac) and Vac/N (VacN), with a two-week interval. Blood was collected weekly and spleens were harvested after chickens were sacrificed. Interleukin-6 (IL-6) and tumor necrotic factor-α (TNF-α) gene expression in peripheral blood mononuclear cells were analyzed by Real-Time PCR. Antibody response was assessed by haemagglutination inhibition (HI). Cellular activity was quantified by MTT assay. Results showed that the most IL-6 and TNF-α gene expression was observed in AgF group (P < 0.01). The lowest gene expression among vaccinated groups was observed in Ag group for IL-6 and Ag and Vac group for TNF-α. The highest HI titer was observed in Vac, VacN, AgF and AgT groups. The AgF group showed the highest cellular activity (P < 0.01). In conclusion, flagellin-adjuvanted groups showed a pro-inflammatory effect and acted similarly to or better than the Vac group. Hence, flagellin can be proposed as a potential adjuvant for ND vaccine. [ABSTRACT FROM AUTHOR]