Viral vector, a key raw material for cell therapy
一、Introduction
Gene transfection is a key step in cell therapy, which refers to the delivery of plasmid DNA containing target genes to cells and their expression in cells, and has been widely used in gene structure and function analysis, gene expression and regulation, gene therapy and transgenic animals. According to the different delivery systems, it can be divided into viral vectors and non-viral vectors. As a good tool for gene delivery, viral vector has its irreplaceable advantages, such as high efficiency of viral vector mediated transfection and small damage to cells. Viral vectors commonly used in cell therapy mainly include retroviral vectors and lentiviral vectors. Non-viral methods include chemical transfection, biological method and physical method. At present, the common means of cell therapy industrialization is still viral vector as its delivery mode.
二、RNA virus vector
There are two main RNA viral vectors currently in common use: gamma Retroviral vector (RV) and Lentivirus vector (LV). Both gamma retroviruses and lentiviruses belong to the retrovirus family. Such viruses are well suited for gene delivery because most of their genome can be replaced by targeted transgenes, and once infected with a host cell, their RNA genome is reverse-transcribed into cDNA, which is then stably integrated into the host genomic DNA [1]. Lentiviral vector is a gene therapy vector developed on the basis of HIV-1 (human immunodeficiency virus type I), which can efficiently integrate foreign genes into the genome of dividing and non-dividing cells [2]. Due to its wide host range, long expression time, low immune response and high biosafety, it has become an ideal gene therapy vector. However, the production mode and purification process of lentiviral vectors are complicated, which limits the production scale to some extent. γ retrovirus vectors can carry large fragments of foreign genes, construct stable virus-producing cell lines by microgram level plasmids, and enter target cells with high transduction rate, which have absolute advantages in the industrialization of cell therapy products. However, both gamma retrovirus vectors and lentiviral vectors can have the potential danger of random insertion, but so far, in the application of cell therapy, gamma retrovirus vectors and lentiviral vectors have no safety incidents, to avoid the above risks, scientists designed self-inactivated gamma RV (SIN-gamma RV) vectors, in clinical trials, The vector has been shown to be absolutely safe, with no cases of poor integration or leukemia [3].
三、DNA virus vector
DNA virus vectors mainly include Adenovirus (ADV) vectors, Adeno-associated Virus (AAV) vectors and Herpes Simplex Virus V (HSV) vectors [4]. ADV is an uncoated double-stranded DNA virus whose vector does not integrate into the host cell genome and is the most commonly used vaccine vector. AAV is a single strand DNA parvovirus. AAV vector has the characteristics of wide trend, low immunogenicity and easy production, which is conducive to clinical application. It is also non-pathogenic and rarely integrates into host chromosomes, leading to long-term expression of the transgene [5]. HSV is an enveloped double-stranded DNA virus that can cause latent ganglion infection. The clinical application of HSV vector based gene therapy has focused on cancer therapy, mainly due to its inherent oncolytic ability.
四、Summary
Viral vectors use the molecular mechanism of virus to transmit its genome into other cells for infection, and have the unique advantages of high transduction efficiency and stable transfection ability for cells compared with non-viral vectors. Therefore, viral vectors are often used in basic research, cell and gene therapy, or vaccine development. Whether it is basic research, clinical trials or industrial scale-up, we need to choose the most appropriate viral vector for the purpose of the study.
Reference：
1. Watanabe N, McKenna M. Generation of CAR T-cells using γ-hiv-vector. Methods in cell biology 2022, 167: 171-183.doi.org/10.1016/bs.mcb.2021.06.014
2. Milone M, O'Doherty U. Clinical use of lentiviral vectors. Leukemia 2018, 32(7): 1529-1541.doi.org/10.1038/s41375-018-0106-0
3. Hacein-Bey-Abina S, Pai S, Gaspar H, Armant M, Berry C, Blanche S, et al. A modified gamma -retrovirus vector for X-linked severe combined immunodeficiency. The New England journal of medicine 2014, 371 (15) : 1407-1417.doi.org/10.1056/nejmoa1404588
4. Lundstrom K. Viral Vectors in Gene Therapy: Where Do We Stand in 2023? Viruses, 2023, 15 (3). Doi.org/10.3390/v15030698
5. Li C, Samulski R. Engineering adeno-associated virus vectors for gene therapy. Nature reviews Genetics 2020, 21(4): 255-272.doi.org/10.1038/s41576-019-0205-4
Disclaimer: Shenzhen Cell Valley is committed to the research of cell and gene therapy, in order to promote emerging technologies, so that more people understand the new development of biomedicine. The content of this article is only used for information exchange, and the platform remains neutral on the content, statements and opinions of the article, and does not represent the position and views of Shenzhen Cell Valley. The relevant information in this article should not be used as a diagnosis or treatment, is not a substitute for professional medical advice, and the company's website will not assume any responsibility. The final interpretation of the content of the above statement belongs to the company's website, this statement will apply to the company's website all the time to share the article, thank you for your cooperation! Copyright description: The copyright of the article belongs to Shenzhen Cell Valley, individuals are welcome to forward to the circle of friends, media or institutions without authorization, reproduced in any form to other platforms, will be regarded as infringement. For reprinting, please contact email: contact@sz-cell.com
Gene transfection is a key step in cell therapy, which refers to the delivery of plasmid DNA containing target genes to cells and their expression in cells, and has been widely used in gene structure and function analysis, gene expression and regulation, gene therapy and transgenic animals. According to the different delivery systems, it can be divided into viral vectors and non-viral vectors. As a good tool for gene delivery, viral vector has its irreplaceable advantages, such as high efficiency of viral vector mediated transfection and small damage to cells. Viral vectors commonly used in cell therapy mainly include retroviral vectors and lentiviral vectors. Non-viral methods include chemical transfection, biological method and physical method. At present, the common means of cell therapy industrialization is still viral vector as its delivery mode.
二、RNA virus vector
There are two main RNA viral vectors currently in common use: gamma Retroviral vector (RV) and Lentivirus vector (LV). Both gamma retroviruses and lentiviruses belong to the retrovirus family. Such viruses are well suited for gene delivery because most of their genome can be replaced by targeted transgenes, and once infected with a host cell, their RNA genome is reverse-transcribed into cDNA, which is then stably integrated into the host genomic DNA [1]. Lentiviral vector is a gene therapy vector developed on the basis of HIV-1 (human immunodeficiency virus type I), which can efficiently integrate foreign genes into the genome of dividing and non-dividing cells [2]. Due to its wide host range, long expression time, low immune response and high biosafety, it has become an ideal gene therapy vector. However, the production mode and purification process of lentiviral vectors are complicated, which limits the production scale to some extent. γ retrovirus vectors can carry large fragments of foreign genes, construct stable virus-producing cell lines by microgram level plasmids, and enter target cells with high transduction rate, which have absolute advantages in the industrialization of cell therapy products. However, both gamma retrovirus vectors and lentiviral vectors can have the potential danger of random insertion, but so far, in the application of cell therapy, gamma retrovirus vectors and lentiviral vectors have no safety incidents, to avoid the above risks, scientists designed self-inactivated gamma RV (SIN-gamma RV) vectors, in clinical trials, The vector has been shown to be absolutely safe, with no cases of poor integration or leukemia [3].
三、DNA virus vector
DNA virus vectors mainly include Adenovirus (ADV) vectors, Adeno-associated Virus (AAV) vectors and Herpes Simplex Virus V (HSV) vectors [4]. ADV is an uncoated double-stranded DNA virus whose vector does not integrate into the host cell genome and is the most commonly used vaccine vector. AAV is a single strand DNA parvovirus. AAV vector has the characteristics of wide trend, low immunogenicity and easy production, which is conducive to clinical application. It is also non-pathogenic and rarely integrates into host chromosomes, leading to long-term expression of the transgene [5]. HSV is an enveloped double-stranded DNA virus that can cause latent ganglion infection. The clinical application of HSV vector based gene therapy has focused on cancer therapy, mainly due to its inherent oncolytic ability.
四、Summary
Viral vectors use the molecular mechanism of virus to transmit its genome into other cells for infection, and have the unique advantages of high transduction efficiency and stable transfection ability for cells compared with non-viral vectors. Therefore, viral vectors are often used in basic research, cell and gene therapy, or vaccine development. Whether it is basic research, clinical trials or industrial scale-up, we need to choose the most appropriate viral vector for the purpose of the study.
Reference：
1. Watanabe N, McKenna M. Generation of CAR T-cells using γ-hiv-vector. Methods in cell biology 2022, 167: 171-183.doi.org/10.1016/bs.mcb.2021.06.014
2. Milone M, O'Doherty U. Clinical use of lentiviral vectors. Leukemia 2018, 32(7): 1529-1541.doi.org/10.1038/s41375-018-0106-0
3. Hacein-Bey-Abina S, Pai S, Gaspar H, Armant M, Berry C, Blanche S, et al. A modified gamma -retrovirus vector for X-linked severe combined immunodeficiency. The New England journal of medicine 2014, 371 (15) : 1407-1417.doi.org/10.1056/nejmoa1404588
4. Lundstrom K. Viral Vectors in Gene Therapy: Where Do We Stand in 2023? Viruses, 2023, 15 (3). Doi.org/10.3390/v15030698
5. Li C, Samulski R. Engineering adeno-associated virus vectors for gene therapy. Nature reviews Genetics 2020, 21(4): 255-272.doi.org/10.1038/s41576-019-0205-4
Disclaimer: Shenzhen Cell Valley is committed to the research of cell and gene therapy, in order to promote emerging technologies, so that more people understand the new development of biomedicine. The content of this article is only used for information exchange, and the platform remains neutral on the content, statements and opinions of the article, and does not represent the position and views of Shenzhen Cell Valley. The relevant information in this article should not be used as a diagnosis or treatment, is not a substitute for professional medical advice, and the company's website will not assume any responsibility. The final interpretation of the content of the above statement belongs to the company's website, this statement will apply to the company's website all the time to share the article, thank you for your cooperation! Copyright description: The copyright of the article belongs to Shenzhen Cell Valley, individuals are welcome to forward to the circle of friends, media or institutions without authorization, reproduced in any form to other platforms, will be regarded as infringement. For reprinting, please contact email: contact@sz-cell.com
