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Immunomodulatory Therapies
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Genetic vaccines, which include DNA or RNA vaccines, use the DNA or RNA associated with tumor antigens to produce the antigen at the tumor site, thereby stimulating an immune response. These vaccines use viral or plasmid DNA vectors to deliver an expression cassette containing the coding region for the specific antigen. This genetic material is taken up by resident cells, resulting in endogenous production of the specific antigen. Research on these types of vaccines is also increasing, with over 40 clinical trials underway at the time of writing. For example, one trial involves the use of a neoantigen DNA vaccine in pancreatic cancer patients following adjuvant chemotherapy and surgical resection.
Mechanisms of Antibiotic Resistance in Acinetobacter spp. — Genetics of Resistance
Published in E. Bergogne-Bénézin, M.L. Joly-Guillou, K.J. Towner, Acinetobacter, 2020
Elisha and Steyn (1991b) argued that the resistances encoded by this transposon might be of little clinical significance. However, Tn21 contains recombinational-hot-spots into which additional antibiotic resistance genes can insert. Wohlleben et al. (1989) described Tn21 as a natural expression cassette for antibiotic resistance genes. Its presence in Acinetobacter, albeit flanking genes of little clinical importance, is cause for concern as resistance genes of considerable clinical significance could be acquired easily.
Structural Determination of the Polycystin-2 Channel by Electron Cryo-Microscopy
Published in Jinghua Hu, Yong Yu, Polycystic Kidney Disease, 2019
The first component of the BacMam system (Invitrogen) is a bacmid donor vector that contains an expression cassette flanked by left and right arms of transposon Tn7, so the gene of interest can be integrated into the baculovirus genome bearing a Tn7 attachment site via site-specific transposition. The expression cassette contains a human cytomegalovirus immediate-early enhancer and promoter (CMV promoter), a multiple cloning site for cloning, a gentamicin resistance gene for later bacmid selection, and a polyadenylation signal from simian virus 40 (SV40) for efficient transcription termination. The donor vector also contains a pUC origin of replication and an ampicillin-resistant gene for vector propagation and selection in E. coli.
Use of genetically modified lactic acid bacteria and bifidobacteria as live delivery vectors for human and animal health
Published in Gut Microbes, 2022
Romina Levit, Naima G. Cortes-Perez, Alejandra de Moreno de Leblanc, Jade Loiseau, Anne Aucouturier, Philippe Langella, Jean Guy LeBlanc, Luis G. Bermúdez-Humarán
Heat-shock proteins are a conserved group of proteins (among which are the groESL and DnaKJ-GrpE chaperone complexes) synthesized in response to different stress stimuli such as heat-shock, low pH, UV irradiation, or salts stress. The SICE system is based on the use of the groESL heat shock protein operon promoter from L. lactis. This episomal system is composed of a vector that carries an expression cassette under the transcriptional control of a stress-inducible promoter.49 In this system, the expression of the protein of interest is induced after administration to the host, since the GM bacterium finds different conditions than those of the culture and suffers different types of stress. Heat stress due to the body temperature of the host higher than the optimal growth temperature of the bacteria; and in the case of oral administration, the acid stress during passage through the stomach added to biliary stress in the duodenum are examples of stresses able to induce expression in this system, and allow the in situ production of the molecule of interest. The main advantage of this system is that it does not require the presence of regulatory genes or the induction in cultures before use.50,51
Locked and loaded: engineering and arming oncolytic adenoviruses to enhance anti-tumor immune responses
Published in Expert Opinion on Biological Therapy, 2022
An autonomous expression cassette is composed of an enhancer/promoter region to activate transcription, a transgene (usually a cDNA, sometimes a gene), and a polyadenylation (polyA) signal. Many times, these enhancers/promoters are promiscuous strong viral or cellular elements that will activate in nearly any cell (e.g. from cytomegaloviruses (CMV), Rous sarcoma virus (RSV), EF-1a, etc.). In other cases, these may be cell-specific or ‘cancer-specific’ enhancers/promoters (telomerase, surviving, probasin, etc.). Natural or artificial introns may be inserted between the transcriptional start site and the start methionine to increase mRNA trafficking out of the nucleus to increase the expression [75]. If introns are used, it should be careful not to disrupt normal Ad splicing in the insertion region as described above.
SPLICELECT™: an adaptable cell surface display technology based on alternative splicing allowing the qualitative and quantitative prediction of secreted product at a single-cell level
Published in mAbs, 2020
Christel Aebischer-Gumy, Pierre Moretti, Romain Ollier, Christelle Ries Fecourt, François Rousseau, Martin Bertschinger
In the simplest cases, the protein of interest can be directly tagged, for example, with green fluorescent protein (GFP).5 However, protein function and structure may be altered by the presence of the tag. Therefore, direct tagging is usually not applicable for therapeutic proteins. Other methods rely on the co-expression of a fluorescent protein (e.g., GFP) with the gene of interest, either through an internal ribosome entry site (IRES), using polycistronic vectors or by co-transfection.6–14 However, limitations in the secretory pathway, protein folding or different efficiencies in translation may affect the correlation of expression of the reporter protein and the gene of interest. These limitations are partially overcome by using a transmembrane reporter protein co-expressed with the protein of interest, such as using an IRES in the expression cassette,14–18 or due to a non-optimal start codon,19 even if an expression bias, which could be caused by uncorrelated expression of reporter and gene of interest due to different folding kinetics, may still be possible. In general, the reporter protein needs to be carefully selected in order to avoid toxic effects for the host cell20 or co-purification with the gene of interest.