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Order Lefavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Besides their use as the previously described display tools, the baculoviruses served as the source of polyhedrin, which could be regarded as a special class of highly structured carriers. As mentioned briefly earlier, the polyhedrin is synthesized in massive amounts and forms a protective crystal around the viruses, which allows them to remain viable for many years outside the insect larvae (Rohrmann 1986). The x-ray crystallographic examination of polyhedrins started in early 1980s (Rohrmann 1986). The chimeric AcMNPV polyhedrin proteins carrying an influenza hemagglutinin epitope not only showed influenza-specific antigenic and immunogenic properties but also presented the foreign epitope on the surface of the chimeric occlusion bodies (McLinden et al. 1992). Furthermore, chimeras of the AcMNPV polyhedrin and Trichoplusia ni granulosis virus (TnGV) granulin were constructed (Eason et al. 1998). The results clearly showed that the size and structure of occlusions was affected by the primary structure of the product, although the involvement of other viral proteins in the virion occlusion body assembly and shape complicated interpretation and further application of this system (Chen et al. 2013).
Recombinant Antibodies
Published in Siegfried Matzku, Rolf A. Stahel, Antibodies in Diagnosis and Therapy, 2019
Melvyn Little, Sergey M. Kipriyanov
DNA can be efficiently expressed in cultures of insect cells infected with baculovirus using expression vectors containing the promoter of the gene for polyhedrin. Invertebrate cells are capable of signal peptide cleavage, N- and O-linked glycosylation, proper cellular compartmentalization and extracellular secretion. The expression of recombinant mAb in insect cells offers several advantages with respect to post-translational modifications, stability, yields and applicability. An anti-human CD29 human::mouse chimeric antibody was recently produced in Sf9 cells with a yield of 10-15 mg/109 cells, higher than the level achieved by the parental mouse hybridoma (Poul et al., 1995). The chimeric heavy and light chains were correctly processed and assembled into a normal immunoglobulin that was secreted into the culture medium. The chimeric antibody was found to be glycosylated and reproduced in vitro the functional properties of the parental mAb, including binding affinity and inhibition of lymphocyte proliferation.
Induction of adaptive immune response by self-aggregating peptides
Published in Expert Review of Vaccines, 2018
Jesus Zepeda-Cervantes, Luis Vaca
Some viral proteins self-assemble and can be used to synthesize VLPs. Particularly, we have reported some peptides derived from AcNPV that self-aggregate [65]. AcNPV belongs to the family Baculoviridae [66]. Recombinant baculoviruses are used for different applications, being the most prominent the production of heterologous proteins [67]. In nature, baculoviruses are occluded into occlusion bodies called ‘polyhedra’ which protect occluded baculoviruses from the environment for years. Polyhedrin is the main protein found in the polyhedra [68]. We have synthesized NPs by using the first 110 amino acids of polyhedrin (PH(1–110)). Our in silico analysis suggested that PH(1–110) contains two repeats formed each of two β-sheets followed by an α-helix. Apparently, these structure repeats allow self-aggregating of polyhedrin. The GFP fused in the C-terminus of PH(1–110) does not affect the NPs formation, but when GFP is fused to the C- terminus of PH(110–245) prevents the self-aggregation, resulting in soluble proteins. Most interestingly, PH(1–110) forms polyhedra-like structures but not canonical polyhedra, as it would the full-length sequence of polyhedrin (1–245 amino acids) [65]. These structures can be observed after 3 days of infection (Figure 1).
Development of thermostable vaccine adjuvants
Published in Expert Review of Vaccines, 2021
Particulate formulations stored in solution can suffer from physical instabilities such as aggregation due to their thermodynamically unfavorable state and chemical breakdown of their various components over time, which can be exacerbated by temperature perturbations [105,106]. Several innovative approaches have been reported to impart thermostability to nano/microparticle formulations in solution. A recombinant single-molecule human papillomavirus (HPV) vaccine candidate exploiting the highly thermostable thioredoxin from the hyperthermophilic archaeon P. furiosus as an antigen-presenting nanoparticle scaffold was reported to maintain structural stability for 24 h at 100°C as well as immunogenicity in mice following lyophilization and multiple freeze-thaw cycles [107]. A follow-up study upgraded the original monomeric vaccine into a multiepitope heptameric nanoparticle, though it was less stable, maintaining structural stability for 10 min at 80°C. When tested in mice, the multiepitope nanoparticle vaccine elicited neutralizing antibodies against 10 different HPV viral types including 3 not represented in the vaccine [108]. Similarly, an engineered protein nanoparticle scaffold designed for multimeric display facilitated increased thermostability (and immunogenicity) of a recombinant respiratory syncytial virus (RSV) antigen compared to the recombinant antigen alone [109]. Although the vaccines in these studies were tested with separately added commercial adjuvants, the platforms do offer the possibility of recombinantly expressing protein/peptide-based adjuvants within the system [107]. A related approach involved fusion of a model antigen to the first 110 amino acids of polyhedrin from Autographa californica multiple nucleopolyhederovirus to produce a protein construct that self-aggregates into nano- and microparticles, although in this case no exogenous adjuvants were employed. Nevertheless, the nanoparticle construct appeared to have inherent adjuvant properties since long-lasting antigen-specific IgG titers in mice were maintained following storage as a vacuum centrifuged dry powder at room temperature or in solution stored at −20°C or −70°C for up to 1 year [110].