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Leveraging Genome Sequencing Strategies for Basic and Applied Algal Research, Exemplified by Case Studies
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Ariana A. Vasconcelos, Vitor H. Pomin
An example of the production of human therapeutic proteins in transgenic algae has been shown in the work of Tran et al. (2009), where it was possible to synthesize and assemble a human monoclonal antibody (mAb) in chloroplasts of eukaryotic green alga C. reinhardtii. The antibody, 83K7C, is derived from a human immunoglobulin (IgG1) that has its action against the protective antigen of anthrax 83 (PA83). Studies have shown that this antibody blocks the effects of anthrax toxin in animal models (Tran et al. 2009). The 83K7C expressed in the alga was bound to PA83 in vitro with similar affinity to the 83K7C antibody expressed in mammalian cell culture. This work showed that C. reinhardtii chloroplasts have the ability to synthesize and assemble complex and functional human antibodies (Tran et al. 2009).
Anthrax
Published in Meera Chand, John Holton, Case Studies in Infection Control, 2018
The principles of clinical management of cases of cutaneous anthrax are the same as those for any severe necrotizing soft tissue infection: to prevent toxin formation and organism multiplication (antibiotics)to remove the infectious nidus where possible (surgical debridement, usually only in cutaneous disease)to neutralize existing toxin (anthrax immune globulin, anti-anthrax toxin monoclonal antibodies, for example, Raxibacumab)
Bacillus
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Jessica Minnaard, Ivanna S. Rolny, Pablo F. Pérez
After secretion and dissemination, PA binds to cell surface receptors, that is, anthrax toxin receptor 1 (TEM8) and anthrax toxin receptor 2 (CMG2). The latter has the higher binding affinity in vivo.36 The binding of LF or EF to PA requires the proteolytic activation of PA. Indeed, PA83 (83 kDa) splits into PA63 and PA20 by furin or furin-like proteases, with PA63 being the receptor for LF and EF. After the proteolytic cleavage of PA83, PA63 oligomerizes on the plasma membrane of the target cell, binds LF or EF, and is further internalized by receptor-mediated endocytosis.
Efficacy assessment of a triple anthrax chimeric antigen as a vaccine candidate in guinea pigs: challenge test with Bacillus anthracis 17 JB strain spores
Published in Immunopharmacology and Immunotoxicology, 2021
Masoud Abdous, Sadegh Hasannia, Ali Hatef Salmanian, Seyed-Shahryar Arab
It has been argued that compared to recombinant vaccines, the production and consumption of veterinary and human anthrax vaccines is associated with several problems [16]. Numerous animal studies have suggested that in addition to PA, other components of the anthrax toxin such as LF and EF induce the production of toxin neutralizing antibodies and play an important role in vaccination and protection [17]. For this reason, considerable efforts are being directed toward developing new vaccines [4]. Many studies have demonstrated that chimeric antigens with highly reactive epitopes are more effective than single antigen vaccines. Even though a single monoclonal antibody (mAb) that neutralizes one of the anthrax virulence components (PA, LF, EF and capsule), particularly PA, may be sufficient to provide significant protection, a mixture of more than one mAb against different targets or epitopes could maximize the protective efficacy. Such combinatorial therapy would not only broaden the spectrum of protection but may also synergize protective efficacy [17]. In order to complete our previous works, this study was conducted to evaluate the immunogenicity of a triple chimeric protein known as ELP containing the domains selected from EF, LF and PA antigens as an anthrax vaccine candidate in a guinea pig model (Figure 1).
Vaccines against anthrax based on recombinant protective antigen: problems and solutions
Published in Expert Review of Vaccines, 2019
Olga A. Kondakova, Nikolai A. Nikitin, Ekaterina A. Evtushenko, Ekaterina M. Ryabchevskaya, Joseph G. Atabekov, Olga V. Karpova
Virulent strains of B. аnthracis contain two plasmids: pXO1 and pXO2. The рХO1 plasmid carries genes responsible for the synthesis of three protein components of exotoxin – protective antigen (PA), edema factor (EF) and lethal factor (LF) [4]. The pXO2 plasmid encodes genes necessary to synthesize the poly-γ-D-glutamic acid of the capsule [5]. Three-component protein exotoxin and poly-D glutamic acid capsule are the major virulence factors of B. anthracis. Anthrax toxin consists of three nontoxic proteins (PA, LF, EF) that assemble in binary or ternary combinations to form toxic complexes at the surface of mammalian cells [6]. PA is the main subunit of the tripartite complex, providing for the transport of LF and EF into the cytosol, where they exert their toxic effects. LF is a zinc-dependent metalloprotease specific for mitogen-activated protein kinase kinases (MAPKKs, MEKs or MKKs) [7]. EF is a potent calmodulin-dependent adenylate cyclase [8]. Binary complexes PA/LF and PA/EF are also referred to as lethal and edema toxins (LT and ET) [9]. LT is generally acknowledged to cause pathological effects, leading to fatal outcomes [10]. Protective antigen is a central toxin component playing a key role in protecting against encapsulated and unencapsulated B. аnthracis strains. PA-specific antibodies can prevent PA-mediated transportation of LF and EF and neutralize both lethal and edema toxins. The majority of epitopes capable of generating antibodies with toxin-neutralizing activity are mapped on PA [11–13].
Quorum sensing pathways in Gram-positive and -negative bacteria: potential of their interruption in abating drug resistance
Published in Journal of Chemotherapy, 2019
Shafiul Haque, Dinesh K. Yadav, Shekhar C. Bisht, Neelam Yadav, Vineeta Singh, Kashyap Kumar Dubey, Arshad Jawed, Mohd Wahid, Sajad Ahmad Dar
A small peptide (Ala-Trp-Leu-Ser-Gln-leu-His-Ser-Tyr-Asn) has been reported as a polyvalent inhibitor of anthrax toxin and restricts host receptors of B. anthracis that assist entry into the host cell.241 Similarly, synthetic carbohydrate-based compounds, like p-nitro-o-Cl-Ph mannoside, have shown inhibition of fimbriae and FimH-facilitated adhesion to guinea pig intestinal cells with >700-fold higher affinity than methyl mannoside.242 3-sialyl lactose inhibits colonization of H. pylori present in the monkey GI tract.243 Cranberry juice inhibits fimbriae-mediated adhesion of E. coli to the wall of urinary tract.244 Similarly, the pilicide BibC10 restricts the formation of pili and surface adhesion fibers in E. coli and inhibits the usher–chaperone pathway by interacting with PapD.245