Haitham Amer

Cairo University, Virology, Faculty Member

King Saud University, Botany and Microbiology, Faculty Member

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Dr. Amer is currently working as a dean of Faculty of Veterinary Medicine, Egyptian Chinese University, Egypt. He is also a professor of Virology at Faculty of Veterinary Medicine, Cairo University (FVM-CU) and served as a former vice dean for graduate studies and scientific research, and chairman of the Virology department at FVM-CU. Dr. Amer received his PhD in virology from Cairo University in 2006. The main scope of his PhD was the use of baculovirus expression vector system (BEVS) for production of recombinant viral proteins and virus-like particles for use as possible candidates in vaccines and diagnostics. During his master and PhD, he shared in the establishment of BEVS and hybridoma technology for the first time in his university.
Dr. Amer also served as a postdoctoral fellow in the molecular immunology department, Robert Koch Institute, Germany, where he succeeded in the development of new system for accurate mRNA quantification of the Xcr-1 gene using Taqman real-time PCR. Dr. Amer has contributed to 17 research grants (3 as PI, and 4 as Co-PI) funded by foundations in Egypt, Germany, USA, and Saudi Arabia. He shared in conducting pilot studies in the fields of molecular virology, immunology and vaccinology that were reflected in the form of scientific publications (47), thesis (20), presentations in national and international conferences/seminars (30), GenBank submissions (297), and awards (12).
The current research projects of Dr. Amer are focusing on: 1) studying the genetic makeup of the prevalent Egyptian strains of animal and poultry viruses; 2) development of improved tools/kits for diagnosis of virus infections; 3) the use of modern biotechnology techniques for construction and evaluation of new vaccine candidates.
Dr. Amer is currently serving as a general secretary of the Egyptian Society of Virology (since 2022), and the editor-in-chief of International Journal of Veterinary Sciences and Medicine (Q1 Veterinary Sciences), and Veterinary Medical Journal Giza (Since 2022). He is a member of the Institutional Animal Care and Use Committee of Cairo University and the arbitrators for promotion of professors and associate professors (Pre-clinical Veterinary Sciences – Microbiology and Parasitology), Supreme Council of Universities. Dr. Amer also established a new bylaw for the postgraduate studies (Credit hour system) at Faculty of Veterinary Medicine, Cairo University.

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-ILT (2020)

Infectious laryngotracheitis (ILT) is a respiratory disease that causes significant economic loss... more Infectious laryngotracheitis (ILT) is a respiratory disease that causes significant economic losses in the poultry industry worldwide. In this study, ILT outbreaks were reported on 30 farms located in eight Egyptian governorates between January 2018 and May 2019. Gross examination of diseased chickens revealed congestion and hemorrhage of laryngeal and tracheal mucosa with fibrinohemorrhagic casts and/or caseous material in the lumens. Histopathological examination showed epithelial sloughing, syncytium formation, heterophilic exudation, and development of eosinophilic intranuclear inclusion bodies. Infectious laryngotracheitis virus (ILTV) antigen was detected in the tracheal epithelium, infiltrated inflammatory cells, and syncytial cells, using immunohistochemistry. PCR targeting a portion of the thymidine kinase gene was further utilized to confirm the presence of ILTV DNA. The complete coding sequences of three envelope glycoprotein genes, gG, gD, and gJ, and a partial sequence of the infected cell polypeptide 4 (ICP4) gene from samples representing all of the farms and disease outbreaks were determined. Five prototype strains with unique sequences were chosen for detailed molecular characterization. Sequence comparisons and phylogenetic analysis of the partial ICP4 gene revealed that two strains were chicken embryo origin (CEO)-vaccine-like strains, and three were tissue culture origin (TCO)-vaccine-like strains. Analysis of the gJ gene sequence indicated that all of the strains were CEO vaccine-like strains. It was predicted that the latter three strains were recombinants of CEO-and TCO-vaccine-like strains. In conclusion, immunohistochemistry coupled with multigenomic PCR sequencing proved to be efficient for identification and typing of ILTV strains during disease outbreaks. Both CEO-vaccine-like and recombinant virus strains were circulating in Egypt during the 2018 and 2019 outbreaks.

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Structural Virology

For further information see our web site at www.rsc.org vi Preface backbone and side-chain placem... more For further information see our web site at www.rsc.org vi Preface backbone and side-chain placement, NMR also provides dynamic (ensemble) information and crystallography provides a 'snapshot' and is often considered static. Solution approaches, such as limited proteolysis combined with mass spectrometry and small-angle scattering approaches (Chapter 3), also provide dynamic information. In cryo-ET and cryo-electron microscopy (cryo-EM) (Chapter 5), macromolecules are frozen in their native state, allowing for discrete selection of dynamic states to be visualized, albeit at lower resolution. Generally, NMR spectroscopy is utilized for small protein molecules that are flexible, X-ray crystallography for medium-sized proteins and complexes that are compact, whereas very large macromolecular assemblages or membranous protein structures are determined by cryo-EM. The largest issue separating cryo-EM and cryo-ET from crystallography, in addition to size and the limitations of crystal formation, is resolution. Cryo-EM has generally been considered a low-resolution technique, giving reconstructions around 15-30 Å , but with advances in sample handling, instrumentation, image processing and model building, near-atomic resolution structures are now being achieved. For cryo-ET the resolution achieveable is still low. In reality, hybrid approaches, combining NMR, X-ray crystallography and cryo-EM, cryo-ET and solution data, are often adopted, which provides a powerful means of filling gaps which can arise in the structural characterization of large macromolecules. For example, in studies where large viruses cannot be crystallized, subcomponents can be crystallized to obtain high-resolution information, which can then be used to interpret the structure at lower resolution obtained by cryo-EM or cryo-ET. Or atomic structures obtained from homologous viral proteins/virus capsids can be used for 3D homology model building. These approaches permit the pseudo-atomic visualization of interaction interfaces between protein-protein subunits, protein-nucleic acids and protein-lipid in virus capsids and also the visualization of virus capsid-host interactions.

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Hepatitis C Virus I Cellular and Molecular Virology

$Fig. 1 Density gradient and electron microscope analysis of recombinant HCV particles. (a, b) Co-sedimentation of viral RNA and structural proteins. (a) Concentrated culture medium collected from JFH1/E2HA RNA-transfected cells was fractionated using a 10-60% sucrose density gradient. HCV RNA titer in each fraction was determined. (b) Density gradient fractions were further concentrated and analyzed by western blotting for core, El or E2-hemagglutinin. P, cell lysate prepared from JFH1/E2HA RNA-transfected Huh7 cells; N, cell lysate from untransfected Huh7 cells. Arrowheads indicate positions of HCV proteins. (c—f) Electron micrograph of spher- ical structures shown by immunogold labeling. Grids were incubated with a concentrated JFH1 virus stock and then with the E2 monoclonal antibody CBH5 (Hadlock et al. 2000). Bound antibodies were detected with Protein A coupled to gold particles 10 nm in diameter. (c—e) Three representative examples showing the same structure. (f) Control grid coated with concen- trated cell-free supernatant derived from mock-transfected cells. In rare cases, we observed gold particles attached to unstructured protein aggregates. Scale bar, 50 nm (Reprinted from Wakita et al. (2005))$

$Fig. 1 The hybrid nature of HCV particles. Schematic representation of the structure of an enveloped virus (a) and a lipoprotein (b). The structure of HCV was proposed to be something in between, since several lines of evidence suggest that infectious particles circulate in the bloodstream as a hybrid lipo-viro-particle (LVP). (c) HCV particles display a broad buoyant density profile: the density of virions inversely correlates with their infectivity. The association of HCV to host lipoproteins may explain the atypically low buoyant density (<1.10 g/mL) of the most infectious material, that is referred to as LVP. In contrast, the most dense fractions are poorly infectious and can be precipitated by anti-human IgG, suggesting that they might represent immune complexes a) Enveloped virus$

$they link secondary structure elements (Table 2). In 4MWF, C1 is bonded to C6, while C6 is free in 4NX3 since the first two cysteine residues were deleted in that construct. All of the disulfide bond discrepancies are in loop regions, most notably around HVR-3. The reasons for these differences are currently unclear. The E2 protein sequences in the two structural studies were from different HCV genotypes; produced in HEK293T cells, which are known to yield functional envelope glyco- proteins in form of HCVpp; and have various deletions. Both production methods yielded functional eE2 as the full-length ectodomains can inhibit HC Vpp or HC Vcc infection (Kong et al. 2013; Khan et al. 2014). It is worth noting that eEE2 produced in a Drosophila expression system resulted in a different disulfide bonding pattern as determined by mass spectrometry (Krey et al. 2010), although disulfide bond shuffling can result during this procedure. Moreover, it is possible that E2 has different disulfide bonding patterns on the surface of the viron. E2 has been detected as non-covalently associated with El in the ER, whereas El/E2 appear to be covalently bound on secreted virus particles (Drummer et al. 2003; Flint et al. 2004; Vieyres et al. 2010). In fact, mutagenesis studies have suggested that C2, C3, Cll, and C12 are critical for E1/E2 hetero-dimerization (McCaffrey et al. 2012). Furthermore, limited disulfide bond reduction is compatible with HCV entry as well as antibody and CD81 binding (Fenouillet et al. 2008). A HLA Ae is Slee A Ke. K Mes orien | (RTO \chtintee oT oe Bee Paw$

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Proteomics

$based protein purification strategies, such as the use of an antibody specific to the protein(s) of interest. Another antibody-based approach involves immunoprecipitation of phosphorylated proteins using an anti- phosphotyrosine or anti-phosphoserine antibody (Pandey and Mann, 2000). Alternatively, or in addition to immunoprecipitation, phosphorylated proteins can be affinity purified by immobilized metal affinity chromatography (Ahn and Resing, 2001). After affinity purification, the phosphoproteins can be separated by one or two-dimensional electrophoresis and identified by mass spectrometry as described below. This is an efficient means of identifying post-translational modifications. Other chromatography strategies are less specific, such as the fractionation of proteins by charge or hydrophobicity. The objective in these cases is not to identify highly charged or hydrophobic proteins per se, but rather to provide a reproducible means of reducing the complexity of a whole cell lysate and at the same time concentrating the proteins that are fractionated. By generating a number of 2D protein gel images following a series of general, reproducible chromatographic separations, it may be possible to visualize a large fraction of the proteome of an organism of interest (Fig. 2.2).$

$One attempt to overcome these disadvantages has been to use multidimensional liquid chromatography (LC) followed directly by tandem mass spectrometry to separate, fragment and identify proteins (Link et al., 1999). In this process, a denatured and reduced protein mixture is digested with a protease to create a collection of peptides (Fig. 2.6). The peptide mixture is applied to a cation exchange column and a fraction of these peptides are eluted based on charge onto a reverse-phase column. The Current proteomics studies rely almost exclusively on 2D gel electrophoresis to resolve proteins before MALDI-TOF or ESI-MS/MS approaches. A drawback of the 2D gel approach is that it is relatively slow and work intensive. In addition, the in-gel proteolytic digestion of spots followed by mass spectrometry is a one-at-a-time method that is not well suited for high throughput studies. Therefore, considerable effort is being directed towards alternate methods for higher throughput protein characterization.$

$recombination-based cloning systems are available. One such system is based on the bacteriophage A site-specific recombination system. Some phages, such as the A phage, undergo both a lytic and a lysogenic cycle. In the lysogenic cycle, the phages do not multiply but, instead, their DNA integrates into the host chromosome (Ptashne, 1992). Lysogeny occurs when, immediately after infection, the A DNA circularizes and the Int protein promotes the integration of the circular DNA into the chromosome (Fig. 4.5). The Int protein is a recombinase that catalyzes the site-specific recombination between an attachment sequence on the phage DNA (called attP for attachment phage) and an attachment sequence on the E. coli chromosome (called attB for attachment bacteria). An E. coli host protein, Integration Host Factor (IHF), is also essential for the integration of DNA (Landy, 1989). The integration reaction is highly sequence specific and is conservative, i.e., there is no net gain or loss of nucleotides. The site-specific recombination reaction is a type of non-homologous recombination because the attB and attP sites are mostly dissimilar. The sites have a common core sequence of 15 base pairs-GCTTTTTTATACTAA. Because the region of homology is small, the reaction would not occur without the Int protein, which recognizes both the attB and attP sites. The sites resulting from recombination between attB andattP are called attL and attR (Fig. 4.5\Landy, 1989).$

$Figure 7.9. Schematic diagram of a surface plasmon resonance biosensor. One of the binding partners is immobilized on the sensor surface. With the BIACORE instrument. the soluble molecule is allowed to flow over the immobilized molecule. Binding of the soluble molecule results in a change in the refractive index of the solvent near the surface of the sensor chip. The magnitude of the shift in refractive index is relatec quantitatively to the amount of the soluble molecule that is bound. Surface plasmon resonance (SPR) biosensors have become an established method to measure molecular interactions. SPR biosensor experiments involve immobilizing one reactant on a surface and monitoring its interaction with another molecule in solution. SPR is an optical phenomenon used to measure the change in refractive index of the solvent near the surface that occurs during complex formation or dissociation (Jonsson et al., 1991) (Fig. 7.9). The SPR signal is expressed as resonance units (RU) and is proportional to the mass of the molecule in solution interacting with the immobilized ligand. Therefore, the standard experiment involves immobilizing the low molecular weight ligand and detecting the change in signal that occurs when the partner molecule is passed over the immobilization surface in a continuous flow (Schuck, 1997). One of the advantages of SPR is that binding reactions are monitored in real time without the need to label ligands. Hence, SPR can be used to study interactions between proteins, carbohydrates, nucleic acids, lipids and small molecules.$

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RNA Interference

Cover Illustration: A model of the small RNA transcriptional silencing complex is shown with the ... more Cover Illustration: A model of the small RNA transcriptional silencing complex is shown with the transcription bubble and RNAPII (dark blue), Argonaute 1 (green), and the antisense strand of the small RNA (red) bound to nascent mRNA (also red). An epigenetic regulatory complex composed of Ezh2, DNMT3a, and HDAC-1 is also shown (red, blue and green), remodeling the histone. (Computer graphics courtesy to Paula J. Morris).

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Rotaviruses

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Baculovirus and Insect Cell Expression

The insect cell culture/baculovirus system has three primary applications: (1) recombinant protei... more The insect cell culture/baculovirus system has three primary applications: (1) recombinant protein synthesis, (2) biopesticide synthesis, and (3) as a model system (e.g., for studying apoptosis). The fundamental techniques involved in these applications are described throughout this book. In this chapter, the most widely techniques are summarized and the reader is directed to detailed information found elsewhere in this book. Furthermore, many useful tips and the author's personal preferences that are rarely published are discussed in this chapter along with quantitative methods to characterize cell growth, baculovirus infection, and metabolism.

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A practical guide to clinical virology

ISBN 0 471 91978 0 (World excluding Scandinavia and Finland) ISBN 82 419 0038 4 (Scandinavia and ... more

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Avian Influenza (Monographs in Virology)

Bibliographic Indices. This publication is listed in bibliographic services, including Current Co... more Bibliographic Indices. This publication is listed in bibliographic services, including Current Contents® PubMed/MEDLINE Disclaimer. The statements, options and data contained in this publication are solely those of the individual authors and contributors and not of the publisher and the editor(s). The appearance of advertisements in the book is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

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Life Itself: Its Origin and Nature. Francis Crick

Fundamental Virology

Real-time PCR

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Genome: The Autobiography of a Species

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Papers by Haitham Amer

Evaluating two approaches for using positive control in standardizing the avian influenza H5 reverse transcription recombinase polymerase amplification assay

Molecular and Cellular Probes, 2020

Highly pathogenic avian influenza H5N1 virus causes heavy losses in poultry farms worldwide. Mole... more Highly pathogenic avian influenza H5N1 virus causes heavy losses in poultry farms worldwide. Molecular diagnostic techniques like RT-PCR and real-time RT-PCR are considered the gold standard for identification of H5 influenza viruses in clinical samples. These techniques are hampered by the need of well-equipped laboratories, large space requirement, and relatively long time-to-result. Recombinase polymerase amplification (RPA) assay represents an excellent alternative to PCR since it is more simple, rapid, economic, and portable. Reverse transcription RPA (RT-RPA) assay was recently developed for sensitive and specific detection of H5N1 virus in 6-10 min. To ensure the accuracy of the developed assay, two approaches for using a positive control were evaluated in this study. These approaches included: 1) all-in-one (internal positive control; IPC), 2) two-tubes-per-one-sample (external positive control; EPC). Sigma virus (SIGV) RNA and turkey mitochondrial DNA were tested as positive controls in both approaches. For all-in-one approach, both targets (H5 and IPC) were strongly inhibited. In contrast, very good amplification signals were obtained for the two types of EPC with no effect on the analytical sensitivity and specificity of H5 RT-RPA assay in two-tubes-per-one-sample approach. The performance of EPC-based H5 RT-RPA was further validated using 13 tracheal swabs. The results were compared to real-time RT-PCR and proved superior specificity in detecting H5N1 but not H5N8 viruses. Inclusion of EPC did not affect the aptitude of both assays in terms of sensitivity, specificity and reproducibility. In conclusion, the two-tubes-per-one-sample approach was more reliable to control the false negative results in H5 RT-RPA assay.

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Molecular characterization and genetic diversity of the infectious laryngotracheitis virus strains circulating in Egypt during the outbreaks of 2018 and 2019

Archives of Virology, 2020

Infectious laryngotracheitis (ILT) is a respiratory disease that causes significant economic loss... more Infectious laryngotracheitis (ILT) is a respiratory disease that causes significant economic losses in the poultry industry worldwide. In this study, ILT outbreaks were reported on 30 farms located in eight Egyptian governorates between January 2018 and May 2019. Gross examination of diseased chickens revealed congestion and hemorrhage of laryngeal and tracheal mucosa with fibrinohemorrhagic casts and/or caseous material in the lumens. Histopathological examination showed
epithelial sloughing, syncytium formation, heterophilic exudation, and development of eosinophilic intranuclear inclusion bodies. Infectious laryngotracheitis virus (ILTV) antigen was detected in the tracheal epithelium, infiltrated inflammatory cells, and syncytial cells, using immunohistochemistry. PCR targeting a portion of the thymidine kinase gene was further utilized to confirm the presence of ILTV DNA. The complete coding sequences of three envelope glycoprotein genes, gG,
gD, and gJ, and a partial sequence of the infected cell polypeptide 4 (ICP4) gene from samples representing all of the farms and disease outbreaks were determined. Five prototype strains with unique sequences were chosen for detailed molecular characterization. Sequence comparisons and phylogenetic analysis of the partial ICP4 gene revealed that two strains were chicken embryo origin (CEO)-vaccine-like strains, and three were tissue culture origin (TCO)-vaccine-like strains. Analysis of the gJ gene sequence indicated that all of the strains were CEO vaccine-like strains. It was predicted that the latter three strains were recombinants of CEO- and TCO-vaccine-like strains. In conclusion, immunohistochemistry coupled with multigenomic PCR sequencing proved to be efficient for identification and typing of ILTV strains during disease outbreaks. Both CEO-vaccine-like and recombinant virus strains were circulating in Egypt during the 2018 and 2019 outbreaks.

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The emergence of subgenotype ON-1 of Human orthopneumovirus type A in Riyadh, Saudi Arabia: A new episode of the virus epidemiological dynamic

Journal of Medical Virology, 2020

Lower respiratory tract infections caused by Human orthopneumovirus are still a threat to the ped... more Lower respiratory tract infections caused by Human orthopneumovirus are still a threat to the pediatric population worldwide. To date, the molecular epidemiology of the virus in Saudi Arabia has not been adequately charted. In this study, a total of 205 nasopharyngeal aspirate samples were collected from hospitalized children with lower respiratory tract symptoms during the winter seasons of 2014/15 and 2015/ 16. Human orthopneumovirus was detected in 89 (43.4%) samples, of which 56 (27.3%) were positive for type A and 33 (16.1%) were positive for type B viruses. The fragment that spans the two hypervariable regions (HVR1 and HVR2) of the G gene of Human orthopneumovirus A was amplified and sequenced. Sequence and phylogenetic analyses have revealed a genotype shift from NA1 to ON-1, which was prevalent during the winter seasons of 2007/08 and 2008/09. Based on the intergenotypic p-distance values, ON-1 was reclassified as a subgenotype of the most predominant genotype GA2. Three conserved N-glycosylation sites were observed in the HVR2 of Saudi ON-1 strains. The presence of a 23 amino acid duplicated region in ON-1 strains resulted in a higher number of O-glycosylation sites as compared to other genotypes. The data presented in this report outlined the replacement of NA1 and NA2 subgenotypes in Saudi Arabia with ON-1 within 7 to 8 years. The continuous evolution of Human orthopneumovirus through point mutations and nucleotide duplication may explain its ability to cause recurrent infections. K E Y W O R D S lower respiratory tract infections, molecular epidemiology, ON-1, phylogenetic analysis, RSV

format_quoteIn a study of 205 samples, Human orthopneumovirus was detected in 43.4%, emphasizing its impact on pediatric respiratory diseases.format_quote

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Preparation of Hybridomas Producing Monoclonal Antibodies against Aflatoxin B1 as a Tool to Control Hepatocellular Carcinoma The holding company of vaccines and biological products

International Journal of Pharmcology, Phytochemistry and Ethnomedicine, 2019

Hybridomas that secreted antibodies against aflatoxin B1 for multiple uses were prepared using a ... more Hybridomas that secreted antibodies against aflatoxin B1 for multiple uses were prepared using a unique immunization schedule. Aflatoxin B1-BSA conjugate was used for immunization of Balb/c mice. Spleen cells were harvested from the hyper immunized mice to be fused with myeloma cell line (P3NS1) using polyethylene glycol 3000, 50% concentration as a fusogenic agent. The produced hybridomas were selected using HAT selective medium that was replaced by complete HT medium. From the 10 th day after fusion, wells that contain colonies of hybridomas covering 30% or greater of the wells surface were screened for production of monoclonal antibodies against aflatoxin B1 using ELISA. 21 hybridomas were found to be reactive to aflatoxin B1. All were found to belong to IgG2a isotype except one was found to belong to IgM isotype. The prepared monoclonal antibodies and their application to immunoassays represent a useful and rapid quantitative measurement with high affinity and low detection limits in order to purify environmentally occurring levels of this carcinogen specially in areas at high risk for liver cancer.

format_quoteThree Balb/c mice were selected post-immunization due to high antibody titers (≤ 1/1600) confirmed via ELISA, validating immunization success.format_quote

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Epidemiology of respiratory viruses in Saudi Arabia: toward a complete picture

Archives of Virology, 2019

Acute lower respiratory tract infection is a major health problem that affects more than 15% of t... more Acute lower respiratory tract infection is a major health problem that affects more than 15% of the total population of Saudi Arabia each year. Epidemiological studies conducted over the last three decades have indicated that viruses are responsible for the majority of these infections. The epidemiology of respiratory viruses in Saudi Arabia is proposed to be affected mainly by the presence and mobility of large numbers of foreign workers and the gathering of millions of Muslims in Mecca during the Hajj and Umrah seasons. Knowledge concerning the epidemiology, circulation pattern, and evolutionary kinetics of respiratory viruses in Saudi Arabia are scant, with the available literature being inconsistent. This review summarizes the available data on the epidemiology and evolution of respiratory viruses. The demographic features associated with Middle East respiratory syndrome-related coronavirus infections are specifically analyzed for a better understanding of the epidemiology of this virus. The data support the view that continuous entry and exit of pilgrims and foreign workers with different ethnicities and socioeconomic backgrounds in Saudi Arabia is the most likely vehicle for global dissemination of respiratory viruses and for the emergence of new viruses (or virus variants) capable of greater dissemination.

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Animal Health Research Reviews Bovine-like coronaviruses in domestic and wild ruminants

Animal Health Research Reviews, 2018

Coronaviruses (CoVs) produce a wide spectrum of disease syndromes in different mammalian and avia... more Coronaviruses (CoVs) produce a wide spectrum of disease syndromes in different mammalian and avian host species. These viruses are well-recognized for their ability to change tissue tropism, to hurdle the interspecies barriers and to adapt ecological variations. It is predicted that the inherent genetic diversity of CoVs caused by accumulation of point mutations and high frequency of homologous recombination is the principal determinant of these compe-tences. Several CoVs (e.g. Severe acute respiratory syndrome-CoV, Middle East respiratory syndrome-CoV) have been recorded to cross the interspecies barrier, inducing different disease conditions in variable animal hosts. Bovine CoV (BCoV) is a primary cause of gastro-enteritis and respiratory disease in cattle calves, winter dysentery in lactating cows and shipping fever pneumonia in feedlot cattle. Although it has long been known as a restrictive cattle pathogen, CoVs that are closely related to BCoV have been recognized in dogs, humans and in other ruminant species. Biologic, antigenic and genetic analyses of the so-called 'bovine-like CoVs' proposed classification of these viruses as host-range variants rather than distinct virus species. In this review, the different bovine-like CoVs that have been identified in domesticated ruminants (water buffalo, sheep, goat, dromedary camel, llama and alpaca) and wild ruminants (deer, wild cattle, antelopes, giraffes and wild goats) are discussed in terms of epidemiology, transmission and virus characteristics. The presented data denote the importance of these viruses in the persistence of BCoV in nature, spread to new geographical zones, and continuous emergence of disease epidemics in cattle farms.

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DNA vaccine RSV G (2018)

Acta virologica, 2018

Development of potent vaccine for human respiratory syncytial virus (HRSV) that confers better pr... more Development of potent vaccine for human respiratory syncytial virus (HRSV) that confers better protection than natural infection remains a global challenge. Vaccination with naked DNA is considered successful approach for the control of many viral diseases. In this study, the potential of DNA vaccination using full-length attachment gene of HRSV type A Saudi strain cloned in pcDNA3.1 + vector (pcDNA/GA) was evaluated in BALB/c mice. The expression efficiency of pcDNA/GA was first confirmed in HEp-2 cells on RNA and protein levels. Mice immunization with either pcDNA/GA or the positive control formalin-inactivated vaccine (FI-RSV) has generated significant serum antibody concentration in ELISA (7.31±0.418 and 9.76±0.006 µg/ml, respectively) with superior neutralizing activity. Similarly, both immunogens evoked robust HRSV-specific CD8+ T-cell response in ELISPOT assay compared to mice immunized with pcDNA3.1 + vector or saline (negative controls). Challenge of the immunized mice with the wild-type HRSV did not provoke clinical symptoms or mortality in any mice group. On the 7 th day post-challenge, mice were euthanized and lungs were extirpated for evaluation of viral load, histopathological changes and cytokine profile. A significant diminish in the viral load and histology score were concluded in lungs of pcDNA/GA immunized mice compared to those immunized with FI-RSV and negative controls. The pulmonary cytokine profile of pcDNA/GA immunized mice displayed notable upregulation of Th1-associated cytokines while that of FI-RSV immunized mice exhibited high levels of Th2-associated cytokines. In conclusion, the DNA vaccine candidate pcDNA/GA has proven prominent efficacy and safety in mouse model, which encourages further evaluation in clinical trials.

format_quotepcDNA/GA vaccine showed significant efficacy, reducing viral load and favoring Th1 responses over Th2 responses in BALB/c mice, suggesting enhanced protection.format_quote

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