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The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Viruses have no intrinsic means to generate energy so they must rely totally on the metabolic machinery of host cells to synthesize new viral components. During viral replication, the nucleic acid of the virus which composes its genome becomes active within the infected cell and serves as a template to make copies of itself and to produce new viral proteins. These newly synthesized proteins and genomic elements assemble into new infectious virions that are released by cell lysis or by budding from the host cell. In some cases the viral genome may incorporate into the host cell DNA leading to persistent infections that may lead to many changes in the host cell including cancer. The genetic information in the virus genome and in the host cell determines the outcome of the virus-cell interaction.
Order Hepelivirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Figure 16.2 shows the genomic structure of HEV and rubella virus as the most dangerous and the most studied representatives of the Hepelivirales order. Both genomes are monopartite and linear, where HEV genomes are of 7.2 kb and rubella virus genome of 9.7 kb in length. The virion RNAs are infectious and serve as both the genome and viral messenger RNA. The 5’ ends are capped, and the 3’ termini are polyadenylated. The HEV genome consists of three partially overlapping ORFs, where ORF 2 encodes the capsid protein translated by leaky scanning from the bicistronic ORF3–2 subgenomic RNA. The 72 kDa capsid protein comprises 660 aa and contains a hydrophobic stretch of 14–34 aa at the N-terminus, which functions as a signal sequence for its secretion (Jameel et al. 1996). The ORF2 has three potential glycosylation sites at the Asn positions 132, 310, and 562 (Xing et al. 2011) and is involved in virion assembly, attachment to the host cell, and immunogenicity.
Introduction to Vaccination
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Nezih Pişkinpaşa, Ömer Faruk Karasakal
In microorganisms there are some genes that encode antigenic and other important components. These genes are integrated into the genomes of mutant microorganisms by some molecular techniques, and recombinantly these types of vaccines are obtained. These vaccines can also be incorporated into a genetic component, as well as multiple components. The method may vary according to the study. For example, recombinant mutant vaccines can be obtained by combining the gD gene of herpes simplex (HSV), the HA gene of the influenza virus, and the rabies virus glycoprotein gene of the vaccinia virus genome (Nascimento and Leite 2012).
Epidemiological characteristics of acute hepatitis A, 2013–2016: a cross-sectional study in Morocco
Published in Infectious Diseases, 2023
Adnane Karami, Raouia El Fihry, Asmaa Haddaji, Fatima-Zahra Jadid, Imane Zaidane, Hajar Chihab, Ahd Ouladlahsen, Mohamed Tahiri, Pascal Pineau, Khadija Akarid, Soumaya Benjelloun, Sayeh Ezzikouri
In natural infection, HAV appears to elicit the production of antibodies directed predominantly towards a conserved immunodominant neutralisation region. A series of overlapping conformation-dependent epitopes are distributed over the capsid proteins VP1 and VP3 (Viral protein 1 and 3, respectively) [11]. Sufficient genetic diversity exists in HAV to define several genotypes and subgenotypes [12]. The entire nucleic acid sequences of several HAV strains have been determined by molecular cloning [13,14], and a large number of HAV isolates have been characterised by sequencing of short genome segments [15,16]. Virus genome regions most commonly used to define genotypes include the C terminus of the VP3 region, the N terminus of the VP1 region, the 168-bp junction of the VP1/P2A region, the 390-bp region of the VP1-P2B regions, and the entire VP1 region [17,18]. When sequence variation within the VP1/VP2A junction is used, distinct genotypes display 24% nucleotide variations between isolates while subgenotypes have 7.5% nucleotide variation [19]. Six HAV genotypes have been identified. Three (I, II, III) are of human origin, and three (IV, V, VI) are of simian origin [20]. There is currently little or no information about isolates circulating in many developing countries, including Morocco.
Success of nano-vaccines against COVID-19: a transformation in nanomedicine
Published in Expert Review of Vaccines, 2022
Manoj Kumar Sarangi, Sasmita Padhi, Gautam Rath, Sitansu Sekhar Nanda, Dong Kee Yi
In November 2021, “omicron” (B.1.1.529), a novel mutant of SARS-CoV-2 with the highest infectivity yet, was identified in South Africa. It joined previous variants in the pandemic including alpha (α) for B.1.1.7 (UK), beta (β) for B.1.351 (South Africa), gamma (γ) for P.1 (Brazil), and delta (δ) for B.1.617.2 (India) [14]. Since the publication of the initial virus genome, a historic number (in the hundreds) of laboratories worldwide have attempted to develop vaccines, and clinical trials for promising candidates have been completed within an expedited period [15,16]. The implementation of smart technologies with no prior clinical approval resulted in conventional vaccine technologies (based on viral protein fragments or attenuated/inactivated virions) being outcompeted in terms of either development speed or immunoprotective efficiency [17]. Most of these newer vaccine candidates used nanoscale vector systems (Table 1) [18], with many prevailing within this nanoscale (Figure 1) [19]. The acceptance of these non-viral or viral NPs in both concept and practice marked an extraordinary revolution in vaccine therapy, with some members of the scientific community applauding nanomedicine and nanoscience as saviors of humanity. Decades of untiring effort and investment in research and development are now gaining recognition due to the successful mass rollouts of nanoscale vaccines. However, the trivial exaltation of nanomedicine could have been circumvented, followed by consideration, caution, and retrospective thinking about managing the epidemiology of the pandemic.
Understanding and managing the impact of the COVID-19 pandemic and lockdown on patients with epilepsy
Published in Expert Review of Neurotherapeutics, 2022
Giovanni Assenza, Lorenzo Ricci, Jacopo Lanzone, Marilisa Boscarino, Carlo Vico, Flavia Narducci, Biagio Sancetta, Vincenzo Di Lazzaro, Mario Tombini
The development of the vaccines started as soon as the virus genome was published in early January 2020[37]. Recent researches suggest that the willingness of people getting immunization for COVID-19 varies from 55% to 90%[38,39]. Also in the past, vaccine hesitancy has steadily grown, partly due to fear of side effects arising from vaccination[40], in particular among PwE concerned about the implications for the epileptic disorder and ASMs interactions. Anyway, preliminary results suggest that neurological adverse effects of the COVID-19 vaccines are very rare. Cases of demyelinating disease were reported in the viral vector vaccine[40]. Fever was one of the most frequent effects on all platforms, particularly in the mRNA platform. To this regard, a potential risk of febrile seizures or worsening of seizures exist as previously observed with others vaccines as those for diphtheria-tetanus-pertussis and mumps and rubella [41].