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Topic Review
Biography
Topic Review
Viral Vectors for Gene Delivery
Over the course of millions of years, viruses have evolved and adapted to changes in the biological environment which has allowed them to survive and replicate in host cells. Using this feature of viruses, gene therapy research has developed new approaches utilizing viruses and their different genomes as carriers and vectors for the delivery of genes, nucleic acids, and other genetic material to cell target sites.
940
24 Aug 2022
Topic Review
Viral Vectors
Viral vectors can generate high levels of recombinant protein expression providing the basis for modern vaccine development. A large number of different viral vector expression systems have been utilized for targeting viral surface proteins and tumor-associated antigens.
494
23 Apr 2021
Topic Review
Viral Vectored Vaccines
Viral Vectored Vaccines are vaccines that use a viral vector as a carrier to deliver a protein (or antigen) from a pathogen (namely viruses and bacteria) in order to elicit an immune response against this pathogen. The DNA or RNA sequence for this protein antigen is inserted into the genome of the virus vector. The resultant recombinant virus expresses the necessary components of the viral vector so that functional virus particles can be made to express the foreign protein antigen. Viral vectored vaccines are classified by the virus vector they use and whether they can reproduce inside cells to produce new virus particles (i.e., are replication competent) or whether they can only enter cells but do not produce new virus particles (i.e., are replication incompetent or single-cycle replication). Different viral vector backbones can serve different needs for developing preventive and therapeutic vaccines depending on the context and diseases they aim to prevent or treat, respectively.
1.1K
30 Dec 2020
Topic Review
Viral Vector-Based Melanoma Gene Therapy
Gene therapy applications of oncolytic viruses represent an attractive alternative for cancer treatment. A broad range of oncolytic viruses, including adenoviruses, adeno-associated viruses, alphaviruses, herpes simplex viruses, retroviruses, lentiviruses, rhabdoviruses, reoviruses, measles virus, Newcastle disease virus, picornaviruses and poxviruses, have been used in diverse preclinical and clinical studies for the treatment of various diseases, including colon, head-and-neck, prostate and breast cancer as well as squamous cell carcinoma and glioma. The majority of studies have focused on immunotherapy and several drugs based on viral vectors have been approved. However, gene therapy for malignant melanoma based on viral vectors has not been utilized to its full potential yet.
518
30 Jun 2021
Topic Review
Viral Vector-Based Gene Therapy
Gene therapy is a technique involving the modification of an individual’s genes for treating a particular disease. The key to effective gene therapy is an efficient carrier delivery system. Viral vectors that have been artificially modified to lose their pathogenicity are used widely as a delivery system, with the key advantages of their natural high transduction efficiency and stable expression. With decades of development, viral vector-based gene therapies have achieved promising clinical outcomes. Long-term gene therapy involves the administration of a specific genetic material (i.e., DNA or RNA) via a carrier, referred to as a “delivery vector,” which facilitates the entry of the foreign genetic material into target cells. The delivery vectors are of two types: viral vectors and non-viral vectors. The commonly used viral vectors are adeno-associated viruses (AAVs), adenoviruses (Ads), or lentiviruses (LVs).
419
09 May 2023
Topic Review
Viral Vaccine Platforms
The emergence of SARS-CoV-2 variants with decreased susceptibility to the neutralizing antibody responses induced by currently available COVID-19 vaccines raises the possibility of breakthrough infections. Thus, alternative or complementary approaches are needed to develop vaccines able to induce a lasting immunological response. In the case of global public health emergencies, governmental vaccine design can benefit from a range of platform technologies, including conventional vaccines such as inactivated and live-attenuated vaccines, the innovative new class of DNA- and RNA-based vaccines and promising protein-based vaccines. Compared with conventional vaccines, molecular-based platforms may offer a more versatile tool against new emergent viruses, allowing fast, low-cost, and scalable vaccine manufacturing. Essentially, these platforms rely on the use of a system to deliver and present a new antigen (or a synthetic gene) to rapidly target an emergent pathogen. Currently, there are four different platforms used to develop viral vaccines: whole virus, nucleic acid-based, viral vectors, and protein and virus-like particles (VLPs). The choice of platform takes into account many factors, including the way the immune system responds to the specific viral infection, vaccination strategies and policies, and the best technology or approach to create the specific vaccine.
622
29 Apr 2022
Topic Review
Viral Transmissibility of SARS-CoV-2
The emergence of coronavirus disease 2019 (COVID-19), caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global health calamity unprecedented in the modern world. The disease spread worldwide, and to date, there have been over 230 million confirmed cases of COVID-19, including approximately 4.7 million deaths. Mutant variants of the virus have raised concerns about additional pandemic waves and threaten to reverse our progress thus far to limit the spread of the virus.
532
27 Apr 2022
Topic Review
Viral Purification in Vaccine Processing
Viral vectors and viral vaccines are invaluable tools in prevention and treatment of diseases. About 14% of vaccines approved by the FDA involve enveloped viruses, while out of the 15 gene therapy products approved worldwide in 2019, six of them use enveloped viruses, and 39% of gene therapy clinical trials are using enveloped viruses. Enveloped viruses are encased in a lipid bilayer which, in most cases, fuses with the target host cell membrane to infect cells. These enveloped viruses are produced in various systems, including traditional embryonated chicken eggs or more advanced cell culture technologies such as MRC-5 cells, Vero cells and HEK293-derived cell lines. The manufacturing of viral vector and viral vaccine products has always been paved with challenges related to the downstream processing. Purification process unit operations usually start with harvest and clarification, followed by intermediate purification steps, before polishing and formulation steps. Although techniques have greatly improved over the years to generate purer high-quality products and reproducible processes while maintaining or decreasing the cost of goods, regulatory agencies are increasingly stringent regarding product identity and characterization of the end products and level of acceptable impurities as a way to ensure public safety and maintain public trust in this class of medicine.
998
09 Aug 2021
Topic Review
Viral Non-Coding RNAs as Transcriptional Weapons
Viral non-coding RNAs are gaining much value and interest for the potential impact played in host gene regulation, acting as fine tuners of host cellular defense mechanisms. Several viruses are able to produce v-ncRNAs that are frequently expressed at high copy numbers in infected cells. V-ncRNAs are capable of interacting with different host cell pathways leading to the modulation of different biological processes including: 1. regulation of viral and host gene expression; 2. cell survival; 3. viral infection/replication; 4. cell transformation; 5 virus proliferation/propagation . On the other hand, host cells regulate their own ncRNAs expression in order to activate defense mechanisms against virus infection.
501
15 Dec 2022
Topic Review
Viral Myocarditis - From Pathophysiology to Treatment
The pathophysiology of viral myocarditis and its sequelae leading to severe heart failure with a poor prognosis is not fully understood and represents a significant public health issue globally. Most likely, at a certain point, besides viral persistence, several etiological types merge into a common pathogenic autoimmune process leading to chronic inflammation and tissue remodeling, ultimately resulting in the clinical phenotype of dilated cardiomyopathy.
533
05 Jan 2022
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