久久久精品欧美一区二区三区,国产欧美久久久精品影院,亚洲AV福利天堂一区二区三亚洲欧洲日韩国产AⅤ在线,亚洲成av人在线视,四虎国产精品永久地址99自拍三区一级国产片,亚洲男人的天堂久久无在线观看免费黄视频,亚洲一级特黄大片在线播放,国产成人精品区在线观看

Gene Therapy
Home > Application > Gene Therapy > Lentivirus

Lentivirus

Lentivirus (LV) is a sub-type of retrovirus, with particle size of 80-120nm, consisting of a single-stranded RNA sequence, which is transcribed into DNA and can be integrated into the host genome, resulting in persistent infection. Most lentiviral vectors are derived from HIV-1 and retain the ability to integrate into the genome of infected cells. LV is very popular in clinical applications due to its ability to more efficiently transduce non-proliferating or slowly proliferating cells. Recently, multiple clinical trials have used third-generation self-inactivated LV to introduce genes into hematopoietic stem cells for the treatment of primary immunodeficiency or hemoglobinopathies. The most common application of LV is the delivery of introduced genes via chimeric antigen receptors (CARs) or cloned T cell receptors to generate immunity against tumors.

 

For the upstream production of lentivirus, although studies have shown that it is feasible to prepare stable lentiviral vector packaging/production cell lines, which has the potential to improve batch-to-batch consistency, ensure supply and reduce costs, because it can simplify the operation and supply chain of LV production, but often require a long time for cell line development, so the strategy of transient transfection of plasmid DNA based on HEK293T cells is still the main choice for large-scale production of lentiviral vectors. For cell culture, in the development phase, adherent culture is dominant given the need for only small batch volumes, the adherent properties of HEK293T cells and the easy availability of consumables. But as scale-up required higher and more consistent batch sizes, production shifted to suspension culture in rocking or stirred tank bioreactors, and the choice of media and supplements was directly related to production methods. The expansion of the cells is related to the activity and the success of the downstream process. Because the media can affect the stability of the vector and form the feed solution entering the downstream, it needs to be carefully optimized.

 

Lentivirus

 

 

Compared with Adenovirus (AV) or Adeno Associated Virus (AAV), the greater challenge of LV downstream processing is that it is enveloped virus, and its inherent complexity and sensitivity require rapid processing, such as its sensitive to freeze-thaw cycles, salt, pH, shear and buffer osmotic pressure, and the particles have lower thermal stability, with a half-life of 7-8 hr at 37 °C. The downstream process of LV can also be divided into 3 main stages, including harvest and clarification; intermediate purification, which includes one or more concentration and purification steps; polishing, formulation and optionally sterile filtration.

 

LV is extracellular product that is released by the producer cells into the culture fluid, so the quality of the harvest fluid is highly dependent on cell viability, which determines the content of host cell-derived impurities. Clarification is aimed at removing cells and cellular debris, and depth filtration is an easy and economical option for this step, after optimization, it can achieve yields approaching 100%. In order to improve the overall biological safety of the final product and comply with regulatory standards, nuclease treatment is usually required to digest nucleic acids, which is also beneficial to reduce the viscosity of the feed liquid and facilitate subsequent steps. It is usually carried out after the clarification step, but it has also been reported carried out after a further reduction in volume at a more subsequent stage.

 

Chromatography is a key technology in the purification scheme, aiming at the removal of proteins, nucleic acids, low molecular weight impurities and lipids, etc. Anion exchange chromatography operated in bind-elute mode and multi-mode chromatography operated in flow-through mode have been reported, used alone or in combination for the purification of LV, but as mentioned earlier, due to the sensitivity of LV to conditions such as salt and pH, the conditions of the chromatography buffer should be carefully optimized. The use of immobilized metal affinity chromatography and size exclusion chromatography has also been reported, but generally limited to smaller scales. TFF is a fast and robust feed fluid concentration and buffer exchange technology. For LV, MWCO 750kD hollow fiber filter can be selected. A 0.22 μm filter can be used for the sterile filtration of the drug substrate before filling, but considering the large particle size of LV, it is reported that the loss of this step can reach 30-50%, and a strategy to reduce the loss is to perform it before the final TFF step, or use a closed system to achieve fully aseptic processing and skip this step.


Related Products
Contact Us
  • Tel.: +86 021 6434 0155
  • E-Mail: marketing@duoningbio.com
  • Address: Building 30, No. 1525 Minqiang Road, Songjiang District, Shanghai
Message

Copyright ? Shanghai Duoning Biotechnology Co., Ltd. All Rights Reserved Sitemap | Technical Support: Reanod

WeChat
WeChat

Message-

Duoning Biotechnology

+86 021 6434 0155

四虎成人精品在永久免费| 国产精品亚洲综合一区在线观看| 国产精品自在线拍国产手青青机版| 日韩一区二区三区免费播放| 超碰97人人做人人爱国产| 久久久无码精品亚洲日韩| 婷婷四房综合激情五月在线| 国产呦精品一区二区三区网站| 免费高清a级毛片在线播放| 国产精品激情综合久久| 国产欧美日韩精品一区二区三区蜜桃不卡| 夜夜想夜夜玩夜夜爽| 中文字幕在线免费视频| 两个领导斗把我夹在中间| 国产一区二区三区不卡| 被按摩师玩弄到潮喷在线播放| 一本色道久久88综合日韩精品| 国产亚洲色婷婷久久99精品| 国产AV中文字幕乱码高清| 亚洲国产成人超福利久久精品| 国产精品高清一区二区三区| 精品人妻无码专区在中文字幕| 高潮呻吟久久av无码午夜鲁丝片| 国产精品55夜色66夜色| 中文字幕乱视频在线观看| 亚洲精品免费日日日夜夜夜夜| 国产精品亚洲成在人线| 超碰97人人模人人爽人人| 久久国产天堂福利天堂| 熟妇女人妻丰满少妇中文字幕| 亚洲无码视频在线观看| 最近日本电影hd免费观看| 人妻免费久久久久久久了| 国产精品爽爽VA在线观看无码| 免费 无码 国产在线观看p午夜亚洲av中文字字幕| 热99re久久精品国产99热| 亚洲成A人片在线观看无码3D| 人妻少妇精品无码专区二区| 亚洲中文久久精品无码浏不卡| 亚洲六月丁香六月婷婷花| 精品一区二区在线欧美日韩|