HA Molecules Research Articles

Antimicrobial Hyaluronic Acid/Poly(amidoamine) Dendrimer Multilayer on Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Prepared by a Layer-by-Layer Self-Assembly Method.

In this article, we prepared hyaluronic acid/poly(amidoamine) dendrimer (HA/PAMAM) multilayers on a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-4HB)] substrate by a layer-by-layer self-assembly method for antimicrobial biomaterials. The results of ζ potential and quartz crystal microbalance with dissipation (QCM-D) showed that HA/PAMAM multilayers could be formed on the substrate layer by layer. We used QCM-D to show that both the HA outer layer and the PAMAM outer layer exhibited good protein-resistant activity to bovine serum albumin and bacterial antiadhesion activity to Escherichia coli. By a live/dead assay and the colony counting method, we found that the PAMAM outer layer could also exhibit bactericidal activity against E. coli, while the HA outer layer had no bactericidal activity. Both the bacterial antiadhesion activity and the bactericidal activity of the samples could be maintained even after storage in phosphate-buffered saline for up to 14 days. An in vitro MTT assay showed that the multilayers had no cytotoxicity to L929 cells, and HA molecules in the multilayers could improve the biocompatibility of the film.

Synthesis of Hydroxyapatite/Collagen (HA/COL) Composite Powder Using a Novel Precipitation Technique

A new biomimetic precipitation technique was developed to synthesize hydroxyapatite/collagen nanocomposites. The componential and morphological properties of nano-composites were investigated. It was revealed that the inorganic phase in the nano-composite was carbonate-substituted hydroxyapatite with low crystallinity. Indeed both characteristic peaks for HA and Col molecule and shifts of the characteristic peaks have indicated on HA-Col bonding. Morphology studies showed that hydroxyapatite particles with the average size of 50 nm were distributed homogeneously in the polymer matrix. According to the TEM micrographs, inorganic particles were needle-like and had regular crystallographic orientation. These results suggest that the hydroxyapatite/collagen nano-composites are promising biomaterials for bone tissue engineering.

Cocktail of H5N1 COBRA HA vaccines elicit protective antibodies against H5N1 viruses from multiple clades

Pandemic outbreaks of influenza are caused by the emergence of a pathogenic and transmissible virus to which the human population is immunologically naïve. Recent outbreaks of highly pathogenic avian influenza (HPAI) of the H5N1 subtype are of particular concern because of the high mortality rate (60% case fatality rate) and novel subtype. In this study, we have engineered an influenza virus-like particle (VLP) that contains a synthetic, consensus-based HA molecule using a new methodology, computationally optimized broadly reactive antigen (COBRA). Three COBRA H5N1 HA proteins have been engineered based upon (1) human clade 2 H5N1 sequences, (2) human and avian clade 2 sequences, and (3) all H5N1 influenza sequences recorded between 2005-2008. Each hemagglutinin protein retained the ability to bind the appropriate receptors, as well as the ability to mediate particle fusion, following purification from a mammalian expression system. COBRA VLP vaccines were administered to mice and the humoral immune responses were compared to those induced by VLPs containing an HA derived from a primary viral isolate. Using a single vaccination (0.6 ug HA dose with an adjuvant) all animals vaccinated with COBRA clade 2 HA H5N1 VLPs had protective levels of HAI antibodies to a representative isolate from each subclade of clade 2, but lower titers against other clades. The addition of avian sequences from other clades expanded breadth of HAI antibodies to the divergent clades, but still not all of the 25 H5N1 viruses in the panel were recognized by antibodies elicited any one H5N1 COBRA VLP vaccine. Vaccination of mice with a cocktail of all 3 COBRA HA VLP vaccines, in a prime-boost regimen, elicited an average HAI titer greater than 1:40 against all 25 viruses. Collectively, our findings indicate that the elicited antibody response following VLP vaccination with all 3 COBRA HA vaccine simultaneously elicited a broadly-reactive set of antibodies that recognized H5N1 viruses from 11 H5N1 clades/subclades isolated over a 12-year span.

Investigation of adsorptive fractionation of humic acid on graphene oxide using fluorescence EEM-PARAFAC

In this study, the adsorptive fractionation of a humic acid (HA, Elliott soil humic acid) on graphene oxide (GO) was examined at pH 4 and 6 using absorption spectroscopy and fluorescence excitation-emission matrix (EEM)-parallel factor analysis (PARAFAC). The extent of the adsorption was greater at pH 4.0 than at pH 6.0. Aromatic molecules within the HA were preferentially adsorbed onto the GO surface, and the preferential adsorption was more pronounced at pH 6, which is above the zero point of charge of GO. A relative ratio of two PARAFAC humic-like components (ex/em maxima at 270/510 nm and at (250, 265)/440 nm) presented an increasing trend with larger sizes of ultrafiltered humic acid fractions, suggesting the potential for using fluorescence EEM-PARAFAC for tracking the changes in molecular sizes of aromatic HA molecules. The individual adsorption behaviors of the two humic-like components revealed that larger sized aromatic components within HA had a higher adsorption affinity and more nonlinear isotherms compared to smaller sized fractions. Our results demonstrated that adsorptive fractionation of HA occurred on the GO surface with respect to their aromaticity and the sizes, but the degree was highly dependent on solution pH as well as the amount of adsorbed HS (or available surface sites). The observed adsorption behaviors were reasonably explained by a combination of different mechanisms previously suggested.

A Hyaluronic Acid-Chitosan-Gadolinium Nanosphere for Specific Tumor-Targeted MRI Contrast Agent

A hyaluronic acid-chitosan-gadolinium (HA-CTS-Gd) nanosphere is prepared by HA modified CTS nanosphere and the complexation between Gd ions and functional groups in CTS and HA molecule. The nanosphere is used as a novel magnetic resonance imaging (MRI) contrast agent for targeting specific tumor. The results show that the HA-CTS-Gd nanosphere is stable in physiological environment due to the strong Gd chelating interaction between the abundant functional groups in HA and chitosan molecules, which leads to low toxicity. Moreover, the obtained nanosphere reveals a high CD44 targeting efficiency and relaxation efficiency in vitro, and it has a great agency for human colonic and mouse lymphatic tumor MRI in vivo. Thus, the novel MRI contrast agent can be taken up selec- tively by CD44 antigen and used as a potential MRI contrast agents in specific tumor.

A multi-stimuli responsive gold nanocage–hyaluronic platform for targeted photothermal and chemotherapy

Noninvasive and pinpointed intracellular drug release that responds to multiple stimulus is still a formidable challenge for cancer therapy. Herein, we reported a multi-stimuli responsive platform based on drug loaded gold nanocages @ hyaluronic acid (AuNCs-HA) for pinpointed intracellular drug release. These well-prepared nanohybrids could specifically recognize cancer cells via HA-CD44 interactions and be efficiently endocytosed by receptor-mediated process. Subsequently, the coated HA molecules could be degraded in lysosomes, resulting in the release of encapsulated drug. In addition, by taking advantage of the excellent photothermal properties, the AuNCs could accelerate the release of encapsulated drug and induce a higher therapeutic efficacy upon near-infrared (NIR) irradiation. In vitro results confirmed that the encapsulated drug could only be pinpointedly released in intracellular environments, which permitted high therapeutic efficacy against cancer cells and minimized the side effects. Importantly, as compared to that of the two therapies independently, a complete inhibition of tumor growth treated with the combination of chemotherapy and photothermal therapy was observed in vivo. Taken together, our present study provides new insights into developing pinpointed, multi-stimuli responsive intracellular drug release systems for synergistic cancer therapy.

MP21-14 UTILIZING DIETARY SUPPLEMENTS TO TARGET BIOMARKERS OF BLADDER CANCER METASTASIS

You have accessJournal of UrologyBladder Cancer: Basic Research I1 Apr 2014MP21-14 UTILIZING DIETARY SUPPLEMENTS TO TARGET BIOMARKERS OF BLADDER CANCER METASTASIS David Alonzo, Travis Yates, Kelly Hoye, and Vinata Lokeshwar David AlonzoDavid Alonzo More articles by this author , Travis YatesTravis Yates More articles by this author , Kelly HoyeKelly Hoye More articles by this author , and Vinata LokeshwarVinata Lokeshwar More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.842AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES HA and HYAL-1 hyaluronidase family molecules are potential markers for Bladder Cancer (BCa) diagnosis and predicting prognosis and promote tumor growth and metastasis. 4-Methylumbelliferone (4-MU) is an orally bioavailable dietary supplement that inhibits HA synthesis. Epithelial mesenchymal transition (EMT) is the hallmark of invasion and metastasis. Since HA promotes tumor metastasis and EMT, we evaluated the expression of EMT markers in bladder tissues and antitumor effects of 4-MU in BCa models. METHODS Quantitative PCR was used to measure mRNA expression of EMT genes (Beta-catenin, Twist, and Snail) in 66 bladder tissue specimens (27 normal; 39 tumor); follow-up: 26 + or - 4.3 months; median 20 months. The effect of 4-MU (40 – 120 μg/ml) on cell proliferation, apoptosis, intracellular signaling, and the expression of HA receptors and EMT genes were examined in BCa cell lines, 253J-Lung and HT1376. Effect of 4-MU on tumor growth was analyzed in subcutaneous xenografts. RESULTS Among the EMT genes, Snail and Twist were differentially expressed in BCa tissues when compared to normal bladder (P<0.001). Furthermore, elevated Twist expression significantly correlated with metastasis (2-fold increase; P=0.028). Beta-catenin expression negatively correlated with survival (chi square=4.3, p=0.038). At IC50 for HA synthesis, 4-MU inhibited proliferation (∼ 2.5-fold) and induced apoptosis (3-fold) in BCa cells. 4-MU induced caspase-8, -9 and -3 activation and up-regulation of Fas and FADD. 4-MU caused 4-10-fold downregulation of HA-receptors (CD44, RHAMM), and EMT promoters - Beta-catenin, Snail and Twist, but increased E-cadherin expression by 2-fold. In xenograft studies, 4-MU significantly decreased tumor growth (> 3-fold) when treatment was started either on the day of tumor cell injection or after tumors became palpable. No weight loss or serum or organ toxicity was observed in treated mice. Tumors showed reduced microvessel density (∼3-fold) and HA expression but increased TURNEL positive cells. CONCLUSIONS This study shows that expression of EMT determinants correlates with clinical outcome. Furthermore, the non-toxic dietary supplement 4-MU has potent antitumor activity and reverses EMT. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e230-e231 Advertisement Copyright & Permissions© 2014MetricsAuthor Information David Alonzo More articles by this author Travis Yates More articles by this author Kelly Hoye More articles by this author Vinata Lokeshwar More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

H7N3 live attenuated influenza vaccine has a potential to protect against new H7N9 avian influenza virus

After recent emergence of new avian influenza A(H7N9) viruses in humans many people and Governments are asking about H7 influenza vaccine which could provide cross-protection against new viruses, until H7N9 vaccine is prepared from a relevant strain. Here we scientifically justify that available H7N3 live attenuated influenza vaccine (LAIV) can be protective against H7N9 viruses due to the presence of conserved immune epitopes in its hemagglutinin. We used Immune Epitope Database analysis resource to predict B-cell and CTL epitopes distributed across H7N3 HA molecule and assessed their identity with new H7N9 viruses at near 70% and 60% of the epitopes, respectively. In addition, we tested serum samples of volunteers participated in phase I clinical trial of H7N3 LAIV for the presence of anti-H7N9 hemagglutination-inhibition and neutralizing antibodies and found seroconversions in 44.8% of vaccinated persons, which suggests the potential of H7N3 LAIV to protect against new H7N9 avian influenza viruses.

Molecular characterization of a H5N1 highly pathogenic avian influenza virus clade 2.3.2.1b circulating in Vietnam in 2011

The emergence of highly pathogenic avian influenza (HPAI) H5N1 viruses and the risk of a human pandemic have highlighted the need for advance stockpiling of vaccine. Current vaccines may be sub-optimally matched to the actual pandemic virus due to the rapid dissemination and ongoing evolution of avian H5N1 viruses. We report here the evaluation of efficacy of NIBRG-14 vaccine (clade 1 A/Vietnam/1194/2004) against the H5N1 HPAI virus strains circulating in Vietnam. The birds were either vaccinated with a single or booster dose of vaccine by subcutaneous injection; then challenged with three H5N1 HPAI viruses (clade 1, clade 2.3.2.1a and clade 2.3.2.1b) at day 21 post-vaccination (p. v.). The results showed that NIBRG-14 vaccine protected birds from clade 1 and clade 2.3.2.1a infections. Notably, we observed that NIGRG-14 vaccine did not confer protection against clade 2.3.2.1b challenge virus. To get new insights of how H5N1 clade 2.3.2.1b (A/Duck/QuangNgai/1037/11) virus can escape from the host immune response induced by the vaccine, we further analyzed the HA gene - a key virulence determinant of the virus. Amino acid sequence analysis indicated that this virus contained the sequence SPQRERRRK-R/G at the cleavage site in the HA molecule, indicating its high virulence. Additionally, we identified numerous mutations with amino acid substitutions in the hemagglutinin: M226I, I239S located at N-link glycosylation site and 2H, 45N, 53K 120D, 133A and 14N mutations at antigenic site, which can affect receptor specificity as well as viral pathogenicity. Notably, I239S and S133A mutations are unique to A/Duck/QuangNgai/1037/2011, suggesting that it may involve in the virus' ability to evade the host immune system. Taken together, phylogenetic analysis showed that continual mutations in the HA gene may have generated a novel antigenic strain and that probably changed the virulence of the virus and made the H5N1 clade 2.3.2.1b resistant to NIBRG-14 vaccine.

Influenza HA Subtypes Demonstrate Divergent Phenotypes for Cleavage Activation and pH of Fusion: Implications for Host Range and Adaptation

The influenza A virus (IAV) HA protein must be activated by host cells proteases in order to prime the molecule for fusion. Consequently, the availability of activating proteases and the susceptibility of HA to protease activity represents key factors in facilitating virus infection. As such, understanding the intricacies of HA cleavage by various proteases is necessary to derive insights into the emergence of pandemic viruses. To examine these properties, we generated a panel of HAs that are representative of the 16 HA subtypes that circulate in aquatic birds, as well as HAs representative of the subtypes that have infected the human population over the last century. We examined the susceptibility of the panel of HA proteins to trypsin, as well as human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2). Additionally, we examined the pH at which these HAs mediated membrane fusion, as this property is related to the stability of the HA molecule and influences the capacity of influenza viruses to remain infectious in natural environments. Our results show that cleavage efficiency can vary significantly for individual HAs, depending on the protease, and that some HA subtypes display stringent selectivity for specific proteases as activators of fusion function. Additionally, we found that the pH of fusion varies by 0.7 pH units among the subtypes, and notably, we observed that the pH of fusion for most HAs from human isolates was lower than that observed from avian isolates of the same subtype. Overall, these data provide the first broad-spectrum analysis of cleavage-activation and membrane fusion characteristics for all of the IAV HA subtypes, and also show that there are substantial differences between the subtypes that may influence transmission among hosts and establishment in new species.

Effects of Ca(OH)2 assisted aluminum sulfate coagulation on the removal of humic acid and the formation potentials of tri-halomethanes and haloacetic acids in chlorination

The effects of addition of calcium hydroxide on aluminum sulphate (or alum) coagulation for removal of natural organic matter (NOM) and its subsequent effect on the formation potentials of two major types of regulated disinfection byproducts (DBPs), haloacetic acids (HAAs) and trihalomethanes (THMs), have been examined. The results revealed several noteworthy phenomena. At the optimal coagulation pH (i.e. 6), the coagulation behavior of NOM water solutions versus alum dose, showed large variation and a consequent great change in the formation potentials of the DBPs at certain coagulant doses. However, with addition of a relatively small amount of Ca(OH)2, although the zeta potential of coagulated flocs remained almost the same, NOM removal became more consistent with alum dose. Importantly, also the detrimental effect of charge reversal on NOM removal at the low coagulant dose disappeared. This resulted in a steady decrease in the formation potentials of DBPs as a function of the coagulant dose. Moreover, the addition of Ca(OH)2 broadened the pH range of alum coagulation and promoted further reduction of the formation potentials of the DBPs. The enhancement effects of Ca(OH)2 assisted alum coagulation are especially pronounced at pH 7 and 8. Finally, synchronous fluorescence spectra showed that the reduction in DBPs formation potential by Ca(OH)2-assisted alum coagulation was connected to an enhanced removal of small hydrophobic and hydrophilic HA molecules. Ca(OH)2-assistance of alum coagulation appeared to increase substantially the removal of the hydrophilic HA fraction responsible for HAAs formation, prompting further reduction of HAA formation potentials.

Preparation and Recognized Characteristic of Histamine Molecularly Imprinted Polymers

HA MIP was prepared in acetonitrile-ethylene glycol mixed solvent ( 20:1，v/v), HA was used as the template, methacrylic acid (MAA) as the functional monomer, azobisisobutyronitrile (AIBN) as the initiator and ethylene glycol dimethaerylate (EGDMA) as the cross-linker. The UV spectrophotometry was used to demonstrate the interaction between HA and MAA. The adsorption characteristics of MIP to HA have been studied by equilibrium binding experiment and Scatchard analysis. The data obtained show that MIP reached equilibrium within 6 h. It is found that within the studied concentration range one HA molecule is entrapped by two MAA molecules The Scatchard chart shows the apparent maximum binding capacity (Bmax) and the dissociation contents (KD) of MIP are 170.5 μmol/g and 0.18 mmol/L, respctively. The MIP synthesized by this method have better binding ability to histamine and can be applied on the separation and detection of histamine.

Minor Changes in the Hemagglutinin of Influenza A(H1N1)2009 Virus Alter Its Antigenic Properties

BackgroundThe influenza A(H1N1)2009 virus has been the dominant type of influenza A virus in Finland during the 2009–2010 and 2010–2011 epidemic seasons. We analyzed the antigenic characteristics of several influenza A(H1N1)2009 viruses isolated during the two influenza seasons by analyzing the amino acid sequences of the hemagglutinin (HA), modeling the amino acid changes in the HA structure and measuring antibody responses induced by natural infection or influenza vaccination.Methods/ResultsBased on the HA sequences of influenza A(H1N1)2009 viruses we selected 13 different strains for antigenic characterization. The analysis included the vaccine virus, A/California/07/2009 and multiple California-like isolates from 2009–2010 and 2010–2011 epidemic seasons. These viruses had two to five amino acid changes in their HA1 molecule. The mutation(s) were located in antigenic sites Sa, Ca1, Ca2 and Cb region. Analysis of the antibody levels by hemagglutination inhibition test (HI) indicated that vaccinated individuals and people who had experienced a natural influenza A(H1N1)2009 virus infection showed good immune responses against the vaccine virus and most of the wild-type viruses. However, one to two amino acid changes in the antigenic site Sa dramatically affected the ability of antibodies to recognize these viruses. In contrast, the tested viruses were indistinguishable in regard to antibody recognition by the sera from elderly individuals who had been exposed to the Spanish influenza or its descendant viruses during the early 20th century.ConclusionsAccording to our results, one to two amino acid changes (N125D and/or N156K) in the major antigenic sites of the hemagglutinin of influenza A(H1N1)2009 virus may lead to significant reduction in the ability of patient and vaccine sera to recognize A(H1N1)2009 viruses.

Molecular characterization of highly pathogenic avian influenza A (H5N1) viruses isolated from humans in Hunan province, 2006 - 2009

To understand the possible origins, genetic re-assortment and molecular characterization of 4 highly pathogenic avian influenza A (H5N1) viruses isolated from humans in Hunan province, between 2006 and 2009. H5N1 PCR test-positive specimens were inoculated in embryonated eggs while H5N1 virus was isolated and genomes sequenced. Genome homology and genetic molecular characterization were analyzed by BLAST and MEGA 4.0. All gene segments of the 4 viruses were avian in origin. No re-assortment was found between avian influenza A (H5N1) viruses and human seasonal influenza viruses. Viruses that isolated from domestic poultry shared high similarity with the 4 human viruses in gene homology. Data from the whole genome phylogenetic analysis showed that the 4 viruses were in clade 2.3.4, while 2 viruses belonged to genotype V, and another 2 were new genotypes. Results from molecular characterization showed that amino acid sequences of HA cleavage site of the 4 viruses were PLRERRKR/G. All 4 viruses had A160T mutation in HA, a 20 amino acid deletion in the neuraminidase (NA) stalk at position 49 - 68, and a 5 amino acid deletion in the non-structural protein 1 (NS1). Most sites in the HA molecules showed that the viruses preferentially bound to avian influenza virus receptor. However, T192I mutation that might enhance the α 2, 6-linked sialic acid human influenza receptor binding had emerged in HN/1/09 and HN/2/09. D701N mutation of PB2 that increased the virulence in mice was found in HN/1/08. Analysis on drug resistance gene amino acid showed that all 4 viruses were sensitive to amantadine and oseltamivir. Highly pathogenic avian influenza A (H5N1) viruses isolated from humans in Hunan province from 2006 to 2009 were avian in origin, and the 4 viruses belonged to different genotypes. Some mutations that related to virulence and receptor binding positions had emerged in some of the strains.

Genetic drift evolution under vaccination pressure among H5N1 Egyptian isolates

BackgroundThe highly pathogenic H5N1 is a major avian pathogen that intensively affects the poultry industry in Egypt even in spite of the adoption of vaccination strategy. Antigenic drift is among the strategies the influenza virus uses to escape the immune system that might develop due to the pressure of extensive vaccination. H5N1 mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences such an eventuality will entail.MethodsH5N1 was isolated from the pooled organ samples of four different affected flocks in specific pathogen free embryonated chicken eggs (SPF-ECE). A reverse transcriptase polymerase chain reaction (RT-PCR) was performed to the haemagglutingin and neuraminidase. Sequencing of the full length haemagglutingin was performed. Sequence analyses of the isolated strains were performed and compared to all available H5N1 from Egyptian human and avian strains in the flu database. Changes in the different amino acid that may be related to virus virulence, receptor affinity and epitope configuration were assigned and matched with all available Egyptian strains in the flu database.ResultsOne out of the four strains was found to be related to the B2 Egyptian lineage, 2 were related to A1 lineage and the 4th was related to A2 lineage. Comparing data obtained from the current study by other available Egyptian H5N1 sequences remarkably demonstrates that amino acid changes in the immune escape variants are remarkably restricted to a limited number of locations on the HA molecule during antigenic drift. Molecular diversity in the HA gene, in relevance to different epitopes, were not found to follow a regular trend, suggesting abrupt cumulative sequence mutations. However a number of amino acids were found to be subjected to high mutation pressure.ConclusionThe current data provides a comprehensive view of HA gene evolution among H5N1 subtype viruses in Egypt. Egyptian H5N1-AIVs are constantly undergoing genetic changes and reveal a complex pattern of drifts. These findings raise the concerns about the value of using influenza vaccines in correlation with the development of antigenic drift in influenza epidemics.

The Genetic Drift of Indonesian Avian Influenza A H5N1 Viruses During 2003-2008

The avian influenza A H5N1 outbreaks started in 2003 and Indonesia introduced a vaccination campaign in 2004 to control the disease. In 2007, anecdotal reports about reduced vaccine effectiveness were received from commercial farmers. This paper describes the evolution of viruses in Indonesia up till 2008 and focus on viruses from vaccinating farms reporting vaccine failure were compared to viruses isolated from outbreak areas with no vaccination program. Result of the study revealed that viruses from vaccinated chickens had more extensive mutation at the HA molecule compared to chicken and other avian species without vaccination. Substitutions occurred at the HA gene level as well as at NA, M1 and NS1 genes. Viruses isolated and characterized form 2008 vaccinated flocks had substitutions that were unique and different with the old viruses. The recommendation arising from this study to the avian influenza disease control program in Indonesia is that continuous monitoring of genetic character of viruses and the vaccine seed strain should be updated periodically and matched with the virus circulated in the field.

H9N2 influenza virus acquires intravenous pathogenicity on the introduction of a pair of di-basic amino acid residues at the cleavage site of the hemagglutinin and consecutive passages in chickens

BackgroundOutbreaks of avian influenza (AI) caused by infection with low pathogenic H9N2 viruses have occurred in poultry, resulting in serious economic losses in Asia and the Middle East. It has been difficult to eradicate the H9N2 virus because of its low pathogenicity, frequently causing in apparent infection. It is important for the control of AI to assess whether the H9N2 virus acquires pathogenicity as H5 and H7 viruses. In the present study, we investigated whether a non-pathogenic H9N2 virus, A/chicken/Yokohama/aq-55/2001 (Y55) (H9N2), acquires pathogenicity in chickens when a pair of di-basic amino acid residues is introduced at the cleavage site of its HA molecule.ResultsrgY55sub (H9N2), which had four basic amino acid residues at the HA cleavage site, replicated in MDCK cells in the absence of trypsin after six consecutive passages in the air sacs of chicks, and acquired intravenous pathogenicity to chicken after four additional passages. More than 75% of chickens inoculated intravenously with the passaged virus, rgY55sub-P10 (H9N2), died, indicating that it is pathogenic comparable to that of highly pathogenic avian influenza viruses (HPAIVs) defined by World Organization for Animal Health (OIE). The chickens inoculated with the virus via the intranasal route, however, survived without showing any clinical signs. On the other hand, an avirulent H5N1 strain, A/duck/Hokkaido/Vac-1/2004 (Vac1) (H5N1), acquired intranasal pathogenicity after a pair of di-basic amino acid residues was introduced into the cleavage site of the HA, followed by two passages by air sac inoculation in chicks.ConclusionThe present results demonstrate that an H9N2 virus has the potential to acquire intravenous pathogenicity in chickens although the morbidity via the nasal route of infection is lower than that of H5N1 HPAIV.

Thermal, structural and morphological assessment of PVP/HA composites

Composites of poly(vinyl pyrrolidone)/hydroxyapatite (PVP/HA), at variable proportions (100/0; 80/20; 50/50; 20/80 wt%) were prepared and characterized by Fourier transformer-infrared spectroscopy (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and thermogravimetry/differential thermogravimetry (TG/DTG). PVP carbonyl stretching was slightly shifted to lower frequency in composites indicating the formation of hydrogen bonding with HA hydroxyl groups. At the first cycle of heating, the calorimetric curves revealed a broad peak the intensity of which was reduced insofar as the amount of PVP decreased in the composites. This peak was attributed to the PVP enthalpy relaxation. According to the TG/DTG curves, PVP degraded into two steps sharply perceivable in the composites. The first decay was ascribed to the release of the pyrrolidone pendant groups and the following one concerned the burning of the hydrocarbon chains. The HA molecules seem to exert a catalytic action on the PVP degradation.

Antigenic variations of human influenza virus in Shiraz, Iran

Purpose: Influenza virus is a major cause of human respiratory infections and responsible for pandemics and regional outbreaks around the world. This investigation aims to determine the prevalent influenza genotypes during 2005-2007 outbreaks in Shiraz, the capital city of Fars province, southern Iran and compare the results obtained with those of previous study. Materials and Method: Of the 300 pharyngeal swabs collected from influenza patients, 26 were found to be positive by culture and hemagglutination (HA) assays. Typing and subtyping of the isolates carried out by using multiplex RT-PCR and phylogenetic analysis performed on isolated HA genes using neighbour-joining method. Result: Out of 26 positive isolates 12 and 14 were H1N1 and H3N2 respectively. The phylogenetic and amino acid sequence analyses of our H1N1 isolates showed 99-100% genetic resemblance to A/NewCaledonia/20/99 (H1N1) vaccine strain. Most of the Iranian H3N2 isolates varied form A/California/7/2004 vaccine strain in 20 amino acids of which positions 189,226 and 227 were located in antigenic sites of HA1 molecule. These substitutions were not observed in any of the H3N2 subtypes from the same region reported previously. Conclusion: The H3N2 subtype strains prevalent during the 2005/7 influenza outbreak in southern Iran demonstrated a drastic antigenic variation and differed from A/California/7/2004 vaccine strain. The H1N1 subtypes showed a notable resemblance to A/NewCaledonia/20/99 vaccine strain and therefore were predicted to be capable of conferring sufficient immunity against H1N1 subtypes.

Generation, Characterization and Epitope Mapping of Two Neutralizing and Protective Human Recombinant Antibodies against Influenza A H5N1 Viruses

BackgroundThe development of new therapeutic targets and strategies to control highly pathogenic avian influenza (HPAI) H5N1 virus infection in humans is urgently needed. Broadly cross-neutralizing recombinant human antibodies obtained from the survivors of H5N1 avian influenza provide an important role in immunotherapy for human H5N1 virus infection and definition of the critical epitopes for vaccine development.Methodology/Principal FindingsWe have characterized two recombinant baculovirus-expressed human antibodies (rhAbs), AVFluIgG01 and AVFluIgG03, generated by screening a Fab antibody phage library derived from a patient recovered from infection with a highly pathogenic avian influenza A H5N1 clade 2.3 virus. AVFluIgG01 cross-neutralized the most of clade 0, clade 1, and clade 2 viruses tested, in contrast, AVFluIgG03 only neutralized clade 2 viruses. Passive immunization of mice with either AVFluIgG01 or AVFluIgG03 antibody resulted in protection from a lethal H5N1 clade 2.3 virus infection. Furthermore, through epitope mapping, we identify two distinct epitopes on H5 HA molecule recognized by these rhAbs and demonstrate their potential to protect against a lethal H5N1 virus infection in a mouse model.Conclusions/SignificanceImportantly, localization of the epitopes recognized by these two neutralizing and protective antibodies has provided, for the first time, insight into the human antibody responses to H5N1 viruses which contribute to the H5 immunity in the recovered patient. These results highlight the potential of a rhAbs treatment strategy for human H5N1 virus infection and provide new insight for the development of effective H5N1 pandemic vaccines.