Question (2028)
Question
I packaged abm’s lentivector into virus, performed transduction and antibiotic selection. Following selection all my cells died. What should I do?
ABM community
Verified customer
Asked on Mar 24 2025
Answer
We recommend first checking the following parameters:
1. Cell density. If density is too low, this can also result in cell death.
We recommend the following experiments:
Initial Experiment
•Transduce lentivirus into the 293T cell line - one of the easiest cell lines to transduce. If the transduced cells survive selection, then troubleshooting should focus on post-virus production steps. If the transduced cells didn't survive selection, the troubleshooting should focus on virus packaging steps.
Virus Packaging Troubleshooting
•Attempt lentivirus packaging using a GFP expressing control vector. If packaging is successful with the control, then repeat packing of the lentivirus in question with a GFP batch control to ensure no errors with the first production. If no GFP signal is observed after transfection or ~72h after a test transduction of a GFP control lentivirus on 293T cells, then the packaging process needs to be assessed. Packaging process assessment includes reagent quality, cell health, and packaging protocol details.
Post-Virus Production Troubleshooting
•Assess if the correct antibiotic concentration is used. This can be done by performing a drug-killing curve. To set up a drug-killing curve, we recommend using the same culture size and seeding density for your actual selection, and adding a different puromycin concentration to each sample, with the range between 0-1 ug/ml. If the cells are not killed at the 1ug/ml, you may try increasing the range higher concentrations. It is important to identify the concentration that results in >95% cell death in 1-4 days to establish the minimal concentration to use for the selection process.
•Assess if the correct MOI is used to transduce the target cells. This can be done by using a GFP control lentivirus to transduce the target cells at a range around literature-recommended MOIs to determine the optimal MOI for transduction.
•Assess if a transduction enhancer such as the ViralEntry Transduction Enhancer (Cat.No. G515) is necessary. Some cell lines are more difficult to transduce than others and by using a transduction enhancer can lead to increased target cell permeability.
1. Cell density. If density is too low, this can also result in cell death.
We recommend the following experiments:
Initial Experiment
•Transduce lentivirus into the 293T cell line - one of the easiest cell lines to transduce. If the transduced cells survive selection, then troubleshooting should focus on post-virus production steps. If the transduced cells didn't survive selection, the troubleshooting should focus on virus packaging steps.
Virus Packaging Troubleshooting
•Attempt lentivirus packaging using a GFP expressing control vector. If packaging is successful with the control, then repeat packing of the lentivirus in question with a GFP batch control to ensure no errors with the first production. If no GFP signal is observed after transfection or ~72h after a test transduction of a GFP control lentivirus on 293T cells, then the packaging process needs to be assessed. Packaging process assessment includes reagent quality, cell health, and packaging protocol details.
Post-Virus Production Troubleshooting
•Assess if the correct antibiotic concentration is used. This can be done by performing a drug-killing curve. To set up a drug-killing curve, we recommend using the same culture size and seeding density for your actual selection, and adding a different puromycin concentration to each sample, with the range between 0-1 ug/ml. If the cells are not killed at the 1ug/ml, you may try increasing the range higher concentrations. It is important to identify the concentration that results in >95% cell death in 1-4 days to establish the minimal concentration to use for the selection process.
•Assess if the correct MOI is used to transduce the target cells. This can be done by using a GFP control lentivirus to transduce the target cells at a range around literature-recommended MOIs to determine the optimal MOI for transduction.
•Assess if a transduction enhancer such as the ViralEntry Transduction Enhancer (Cat.No. G515) is necessary. Some cell lines are more difficult to transduce than others and by using a transduction enhancer can lead to increased target cell permeability.
ABM Scientific Support
Answered on Mar 24 2025