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Order Tymovirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Marconi et al. (2006) fused two peptides chosen from glycoprotein E2, corresponding to aa 790–860 and aa 854–894, of classical swine fever virus (CSFV) of the Flaviviridae family of the order Amarillovirales (Chapter 22) to the N-terminus of the PVX coat via 2A peptide from FMDV and preceded by the His6 tag. The relatively long, each >40 aa residues, peptide encoding sequences were correctly retained in the PVX construct after three sequential passages in N. benthamiana plants and were replicated with high fidelity during PVX infection. The chimeric virions were able to induce an immune response in rabbits (Marconi et al. 2006).
Regulation of Antiviral Immunity by Mitochondrial Dynamics
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Mohsin Khan, Hasan Imam, Saiful Anam Mir
Classical swine fever virus (CSFV) is an enveloped RNA virus belongs to Flaviviridae family, which is associated with hepatitis C and dengue virus (Gou et al., 2017). In CSFV infected cells, oxidative stress is induced and mitochondrial transmembrane potential is disturbed. CSFV infection induces mitochondrial fission and mitophagy to inhibit host cell apoptosis (Gou et al., 2017). Expression of PINK and Parkin and their mitochondrial translocations are increased during CSFV infection. In CSFV infected cells, Mfn2 was ubiquitinated and degraded via PINK1 and Parkin pathways. During infection of CSFV, Drp1 translocation into mitochondria induces mitochondrial fission that results in mitochondrial fragmentation (Gou et al., 2017). Silencing of Drp1 and parkin during CSFV infection upregulate apoptotic signals, preserves mitochondrial proteins and reduces viral replication (Gou et al., 2017). All these events clearly indicate that mitochondrial fission and mitophagy induced by CSFV are required to increase viral persistence and cell survival.
Genetic engineering strategies for construction of multivalent chimeric VLPs vaccines
Published in Expert Review of Vaccines, 2020
Xinnuo Lei, Xiong Cai, Yi Yang
To elicit a high-level B cell response, foreign antigens are usually inserted into the surface exposure region of chi–VLPs [47,48], as such, the conformational location of both N/C-ter of Cap (embedded inside or facing to the surface of chi-cVLP) generally determines the feasibility and efficiency of this strategy. Currently, the most successful chi VLPs were designed and constructed with this strategy. As shown in Figure 1, N/C-ter of Cap of the four representative VLPs, HBV, HPV, PCV2, and tobacco mosaic virus (TMV) are partially exposed on the surface of cVLPs, which were able to be utilized for cVLPs development. Back in 1995, Gordon et al. fused 189 aa residues derived from P. falciparum circumsporozoite protein (CSP) to the N-ter of hepatitis B surface antigen (HBsAg). The chimeric HBsAg was expressed in yeast to produce stable chi–VLPs, referred to as RTS,S, which was later developed as the first malaria vaccine (Mosquirix®) against Plasmodium falciparum [49]. A counter example is a chi–VLP created based on PCV2, the study revealed that insertion of T-cell or B-cell epitopes of classical swine fever virus (CSFV) into the N-ter truncated PCV2 Cap failed to induce the production of neutralizing antibodies (NAbs) against CSFV [46]. The possible explanation is that N-ter of the PCV2 Cap is buried inside the cVLPs as shown in 3D structure by cryogenic electron microscopy (Cryo-EM) [50]. As a result, the inserted CSFV epitopes at the N-ter of the Cap could be hardly exposed on the surface of PCV2 cVLPs and presented to B cells that could produce NAbs.
Gold nanoparticles for preparation of antibodies and vaccines against infectious diseases
Published in Expert Review of Vaccines, 2020
The capsid (Cap) protein of a pathogenic porcine circovirus was conjugated to 23-nm GNPs [116]. In vitro studies showed that GNPs contributed to Cap protein phagocytosis. Mice immunized twice subcutaneously with GNP/Cap showed high production of virus-neutralizing antibodies. Similar results were obtained with classical swine fever virus antigen [117].
Signal peptide peptidase: a potential therapeutic target for parasitic and viral infections
Published in Expert Opinion on Therapeutic Targets, 2022
Christopher Schwake, Michael Hyon, Athar H. Chishti
Several other notable human viruses utilize host SPP during their infective cycle. (Z-LL)2 ketone inhibition resulted in Ebola virus glycoprotein particle entry blockage through cathepsin B/L-mediated entry [82]. (Z-LL)2 ketone was shown to directly inhibit recombinant cathepsin B and L that utilize cysteine residue mediated catalysis [82], a finding consistent with the fact that (Z-LL)2 ketone was first developed as a cysteine protease [20]. A closely related filovirus, Lake Victoria Marburgvirus Musoke (MARV), was not inhibited effectively with (Z-LL)2 ketone presumably due to its CatB/CatL-independent cell entry [83]. (Z-LL)2 ketone was also effective at inhibiting cell entry of pseudotyped particles containing MERS-CoV and SARS-CoV glycoproteins through inhibition of cathepsin L [82], which is required for SARS and MERS entry [84]. Fewer studies have examined the role of SPP in other viral infections. The Bunyamwera Orthobunyavirus glycoprotein is processed by both signal peptidase and signal peptide peptidase [85]. This observation served as an important example of viral protein precursor cleavage in the genus Orthobunyavirus, which could lead to the development of targeted interventions of SPP-mediated processing in future studies. In classical swine fever virus (CSFV), SPP was found to play a crucial role in increasing capsid protein quantity [86]. During infection, the 26S proteasome degraded viral capsid proteins; however, further cleavage of the C-terminal residues by SPP prevented host degradation of the capsid protein by the proteasome [87]. The C-terminal processing of CSFV core protein was directly blocked through inhibition with (Z-LL)2-ketone. Incubation with (Z-LL)2-ketone resulted in a 100-fold reduction in virus viability [86]. The foamy virus envelope protein was found to act as a substrate for SPPL3 and SPPL2a/b [88]. More studies will be needed to determine the importance of host SPP processing steps during viral infection of these pathogens, thus permitting this pathway as a novel mechanistic therapeutic target for pharmacological intervention. Specifically, inhibition of viral glycoprotein processing may be an effective broad antiviral strategy in the future (Table 3).