ABSTRACT
Background & Aim: The new UCOE models we have recently developed, tested on many cell groups (including mouse ES and human iPS cells) and human mAb recombinant production studies as well, shows a powerful resistance to DNA methylation- mediated silencing and provides a higher and stable transfection profile. By the urgent need of vaccine development for COVID-19 during the pandemic, in this study we aimed to produce a potential recombinant vaccine by using the new generation UCOEs models of our own design. Methods, Results & Conclusion(s): Existing new-generation UCOE models and standard plasmid vectors to be used as control group were provided. Then, the sequences related to the PCR method were amplified for sufficient stock generation and cloning experiments. Verification in the plasmid vector was carried out in gel electrophoresis. Transfection of 293T cells was performed with clone plasmids carrying antigen genes and plasmids carrying genetic information of lentivirus units for the production of lentiviral vectors. Afterwards, 293T cells produced lentiviral vectors carrying antigen genes. Harvesting of these vectors was carried out during 48th and 72nd hours. Afterwards, CHO cells were transduced with appropriate quantity of lentiviral vectors. Isolation and purification of targeted proteins from the relevant medium were performed by HPLC and Q-TOF methods. A part of the spike and nucleocapsid gene sequences of COVID-19 were firstly cloned into our UCOE models. These UCOEs plasmids were then transferred into 293T cells along with plasmids carrying the genes that will form the lentivirus vectors (LVs). After harvesting and calculation of LV vector titers, the cloned vectors were then transfected into the CHO cells which the targeted recombinant production of the antigen proteins will be carried out. Antigenic structures were then isolated from the culture medium of CHO cells in following days for confirmation. Using HPLC and qTOF mass spectrometer methods, these structures in the medium were confirmed to be the units of spike and nucleocapsid proteins of the COVID-19 virus. In order to produce large amount of the recombinant antigens, the culture was then carried out with bioreactors in liters. At the final stage, these recombinantly produced antigen proteins were tested on rats to measure their immunogenic responses, and the study recently been completed successfully as a potential recombinant vaccine against COVID-19.Copyright © 2023 International Society for Cell & Gene Therapy
ABSTRACT
Background: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a novel and highly pathogenic coronavirus and is the causative agent of COVID-19, an ongoing pandemic that has posed a serious threat to public health and global economy. Thus, there is a pressing need for therapeutic interventions that target essential viral proteins and regulate virus spread and replication. To invade the host cell, the receptor-binding domain (RBD) of SARS-CoV-2 Spike protein binds to the host cell's ACE2 receptor, followed by cleavage events that allow the Spike protein to fuse with the host cell membrane. Thus, the essential role of Spike protein in ACE2 receptor binding and viral fusion makes it a prime target for therapeutic interventions. Method(s): We performed molecular docking and molecular dynamics (MD) simulation-based virtual screening against SARS-CoV-2 RBD/ACE2 interface using a commercial library of 93,835 drug-like compounds. Compounds with promising docking poses and scores were selected for further MD simulation refinement, from which ten lead compounds were identified. Antiviral potencies of ten lead compounds were evaluated against lentiviral vectors pseudotyped with SARS-CoV-2 Spike to down select to a single lead compound, SAI4. ELISA-based assays were employed to determine the binding affinities of SAI4 to recombinant SARS-CoV-2 RBD. Antiviral potential of SAI4 was validated against genuine SARS-CoV-2 in a BSL3 setting. Result(s): We identified SAI4 as a candidate small molecule, which inhibited SARS-CoV-2 pseudovirus entry with IC50 value of ~18 muM. We determined that SAI4 binds RDB with a Kd of ~20 muM. Using cells engineered to express ACE2 and cells that express physiological levels of ACE2, we found that SAI4 inhibited SARS-CoV-2 pseudovirus entry at both engineered and physiological ACE2 levels. We validated the antiviral potential of SAI4 against genuine SARS-CoV-2 and HCoV-NL63. Lastly, we demonstrated antiviral potential of SAI4 against four SARS-CoV-2 variants of concern (alpha, beta, gamma, and delta). Conclusion(s): Using virtual screening, we identified SAI4 as the promising hit compound which displayed inhibitory activities against SARS-CoV-2 entry and its four variants of concern. Thus, our study will pave the way for further development of small molecules for therapeutic targeting of SARS-CoV-2 entry to combat the COVID-19 pandemic.
ABSTRACT
Background & Aim: The recent supply chain crisis highlights a need to establish alternative manufacturing (MFG) protocols ensuring continuity of existing and new cell therapy (CT) clinical trials. Our academic CT program, and likely others, experienced purchasing delays and restrictions caused by diversion of critical supplies to meet COVID-19- related research demands and/or reduced vendor capacity due to resource constraints, including attrition of skilled workforce. Mitigation strategies aimed at creating process redundancies overcome production challenges resulting from a scarcity of goods. Here, we validated an alternative ex vivo culture system to clinically MFG lentiviral vector (LV) modified CAR T cells due to limited availability of cell expansion culture bags for the Wave bioreactor, a critical unit of operation that we have used to successfully MFG thousands of gene-modified T cell products for 30+ clinical trials. Methods, Results & Conclusion: The disposable G-REX culture vessels were compatible and seamlessly integrated with our closed system platform. Mesothelin CAR T cells were manufactured in parallel via the G-REX or conventional Wave bioreactor using consented patient starting material. Critical quality attributes of the final T cell products, including viability, transduction efficiency, phenotype and function were assessed. Transduction efficiencies assessed by flow cytometry and/or molecular qPCR were lower in products generated in the G-REX compared to the wave using the same multiplicity of infection. However, at least 50-fold expansion was achieved, with cell viabilities greater than 90% and with comparable cellular phenotypes. The Meso CAR T cells generated by either process were capable of eliciting CAR-mediated cytotoxicity and effector cytokine production. Strikingly, 2-4 billion T cells were harvested from a starting seed number of just 50 million T cells in the 1L G-REX, which may be sufficient to meet most protocol- specified cell therapy doses, suggesting that a full apheresis collection may not be needed. Notably, this process required just 1/3 of the starting material, 1/5 of the media and decreased manual effort through culture duration compared to the Wave. Additionally, the reduced reliance on specialized capital equipment combined with a small footprint enables simultaneous MFG of several immunotherapy products. These advantages propose consideration in replacement of current expansion platform as well as validating an alternative process for MFG CAR T cells.