PackGene provides end-to-end lentiviral vector design and packaging services with superior quality driven by a blend of proprietary technologies and reagents. Our advances in lentivirus packaging optimize recombinant lentivirus production, especially for third-generation lentiviral vector systems. Benefits of this optimization include improvements in titer, purity, viability, and consistency in producing your custom lentivirus. Recombinant lentivirus is derived from modifications of the HIV-1 genome and stands as the most widely used viral vector for effective gene delivery in mammalian cells. In contrast to plasmid DNA vectors that only facilitate transient and episomal expression, lentiviral vectors enable permanent transgene expression by integrating foreign genes into the host cell’s genome. The design of a recombinant lentivirus involves both substituting a portion of the lentivirus genome with a target gene and enhancing the virus’s capability to infect a broad range of cell types, including neurons, liver cells, heart muscle cells, tumor cells, endothelial cells, and stem cells. The use of recombinant lentiviruses for transgene expression in mammals can be well tolerated and induces minimal immune responses. Thus, cell transfection with lentiviruses is appropriate for both in vitro and in vivo applications.
PackGene’s lentiviral products are versatile, with the capability to drive the expression of coding or non-coding genes like shRNA and microRNA. We provide 3rd-generation systems containing a modified 3’ LTR with a “self-inactivating nature”. This means that our 3rd-generation viruses are capable of infecting target cells but do not continue to infect other cells nor do they use host cells to produce new viral particles.
Efficient and prompt
delivery time as quick as 8 to 12 business days
Accurate titer measurements
post-transduction qPCR eliminates any overestimation concerns
Professional technical support
a response to any inquiries or requests will be delivered within 1 business day
Enhanced Safety
One-stop solution
from vector design and virus packaging to thorough analysis and testing
Secure shipping
Dry ice and cold chain logistics to maintain optimal efficacy
| In vitro grade | In vivo grade | |
| Application | Cell culture | In vivo study |
| Quantity | 5E7 TU and up | 5E7 TU and up |
| Functional titer (post-transduction qPCR) |
≥1E+8TU/mL | ≥1E+8TU/mL |
| Physical titer (p24 or qPCR) |
≥ 2E+9 GC/mL ≥ 1E+10 LP/mL |
≥ 2E+9 GC/mL ≥ 1E+10 LP/mL |
| Purification | Crude | Sucrose gradient |
| QC (see add-on QC below) |
Post-transduction qPCR, fluorescence images if contain fluorescence | Post-transduction qPCR, fluorescence images if contain fluorescence |
| Timeline | Start from 7 business days | 3-4 weeks |
- Lentivirus will be offer at a concentration of >1E8 TU/mL
- Yield is not guaranteed for constructs with elements detrimental to the viral packaging process. This includes but is not limited to, toxic genes, genes that disrupt viral packaging, genes that disrupt cell or lentiviral RNA integrity, sequences prone to rearrangement or secondary structures, nucleoproteins, transmembrane proteins, receptor genes, and gene segments with over 6.5kb between LTRs.
Need control virus?
Off-the-shelf (CMV.Gene.EF1.GFP-T2A-Puro.WPRE) are offered at 2E7 TU per vial at ≥1E+8TU/mL. with both in vitro and in vivo grade available.
Accurate titer measurements by post-transduction qPCR
| Category | QC test | Description | Release standard |
| Titer | qPCR | qPCR quantifies the number of viral genome copies providing an accurate measure of the viral titer | Report titer |
| Post-transduction qPCR | Infection of cells followed by quantitative qPCR to determine the titer of lentiviruses |
Report transduction unit |
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| Transduction test | Gradient dilution of infected cells and count of fluorescent cells |
Provide bright field and fluorescent microscopy images |
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| p24 Elisa* | ELISA test for the p24 protein, a core capsid protein of HIV that is used to measure lentivirus titer |
Report titer |
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| Contamination | Mycoplasma test* | Measure mycoplasma DNA by PCR | Guaranteed negative |
| Bioburden* | Plate count method: Quantification of live microorganisms (fungi, bacteria, etc.) using colony-forming units (CFUs) | No growth on the agarose plate |
|
| Safety | Endotoxin LAL* | Measure endotoxin level by gel clot assay | Report |
* QC with additional charges
Learn more about our lentivirus QC tests
Post-transduction qPCR: This test uses quantitative polymerase chain reaction (qPCR) to determine the amount of viral RNA present in cells after they have been transduced with lentivirus. This assay is used to determine the efficiency in which a lentivirus delivers its genetic material into host cells.
Transduction test: In this test, a sample of cells are infected with the lentivirus, and transfection efficacy is determined by measuring either transgene expression or the expression of a reporter gene such as GFP (Green Fluorescent Protein). This assay is used to evaluate the efficiency with which the lentivirus drives transgene expression in target cells.
| Bright-field | Fluorescent field | Bright-field | Fluorescent field | ||
| 96-well plate, 1.5E+04 cells/well, virus 18µL, 72hrs after transduction |  |
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96-well plate, 1.5E+04 cells/well, virus 1.8E-03µL, 72hrs after transduction |  |
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| 96-well plate, 1.5E+04 cells/well, virus 1.8µL, 72hrs after transduction |  |
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96-well plate, 1.5E+04 cells/well, virus 1.8E-04µL, 72hrs after transduction |  |
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| 96-well plate, 1.5E+04 cells/well, virus 1.8E-01µL, 72hrs after transduction |  |
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96-well plate, 1.5E+04 cells/well, virus 1.8E-05µL, 72hrs after transduction |  |
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| 96-well plate, 1.5E+04 cells/well, virus 1.8E-02µL, 72hrs after transduction |  |
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96-well plate, 1.5E+04 cells/well, virus 1.8E-06µL, 72hrs after transduction |  |
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p24 ELISA: The p24 antigen is a component of the HIV virus particle and can be used as a marker for virus quantity. In this test, ELISA is used to measure the concentration of p24 viral particles in a lentivirus preparation. This assay is used to quantify the titer of a lentiviral sample.
Mycoplasma test: Mycoplasma contamination is a common and serious issue in cell culture and can substantially reduce cell growth and lentivirus production. A mycoplasma test is conducted to ensure that the cell cultures used in lentivirus production are free from mycoplasma contamination.
Bioburden: This test measures the total number of living microorganisms present in the lentivirus product or on the surfaces of production equipment. The bioburden test is important for assessing the sterility and overall cleanliness of the production process.
Endotoxin LAL: The Limulus Amebocyte Lysate (LAL) test is used to detect and quantify bacterial endotoxins, which are components of the outer membrane of Gram-negative bacteria. Endotoxins can be potent immunostimulatory molecules, and their presence in lentivirus preparations can induce inflammatory responses in patients. Therefore, the Endotoxin LAL test is crucial for confirming that the lentivirus product is safe for in vivo applications or clinical use.
PackGene, a prominent provider in the field of gene therapy, offers a diverse range of lentiviral vectors that have been designed for several gene manipulation applications. Available vectors are tailored to facilitate gene overexpression or to drive the expression of shRNA.
Gene Overexpression Lentiviral Vectors: These vectors are engineered to increase the expression of a specific gene within a target cell. They are commonly used to study the function of a gene, to model a disease, or in various therapeutic applications.
PackGene’s overexpression vectors contain a strong promoter to drive high levels of transgene expression. We will first clone your gene of interest into any of our pre-designed vectors before packaging that vector into lentivirus. Following transduction, your gene will be integrated into the host cell’s genome, which results in sustained expression of the gene. This approach is valuable for understanding gene function, protein interactions, and potential therapeutic interventions where increased expression of a particular gene may be beneficial.
PackGene’s ready-to-use LVV transfer plasmid backbones are listed below. You may also design your own LVV transfer plasmid, and we will synthesize it for you.
| Vector ID | Promoter | GOI capacity | Promoter for Selection marker | Selection marker |
| XL03C | CMV | 3.3Kbp | EF1 | CopGFP-2A-Puro |
| XL10C | CMV | 4Kbp | EF1 | mRuby2 |
| XL11C | CMV | 4Kbp | EF1 | mCitrine |
| XL12C | CMV | 4Kbp | EF1 | EYFP |
| XL22C | CMV | 3.2kp | EF1 | mCherry-2A-Neo |
| XL23C | EF1 | 4.2kb | T2A | CopGFP |
shRNA Lentiviral Vectors: Short hairpin RNA (shRNA) vectors are used for gene silencing applications. PackGene’s shRNA vectors are designed to express shRNA sequences that are processed into small interfering RNA (siRNA) within the cell. These siRNA molecules guide cellular machinery to target mRNA to facilitate mRNA, degradation and thus reduce expression of the target gene. shRNA lentiviral vectors are crucial tools in gene function studies, allowing researchers to knock down the expression of specific genes and to observe the resulting phenotypic changes. They are also used in therapeutic research, particularly in diseases where the downregulation of a gene product may be beneficial.
| Vector ID | Promoter | Promoter for Selection marker | Selection marker |
| XL03B | U6 promoter | EF1a | EGFP-2A-Neo |
| XL04B | U6 promoter | CMV | CopGFP-2A-Puro |
| XL05B | U6 promoter | CMV | Puro |
| XL06B | U6 promoter | PGK | Puro-lRES-mCherry |
| XL07B | H1 promoter | CMV | CopGFP |
| XL08B | H1 promoter | CMV | CopGFP-2A-Puro |
| XL09B | H1 promoter | CMV | Puro |
| XL012B | U6 promoter | CMV | Neo |
miRNA Lentiviral Vectors: MicroRNA (miRNA) are small, non-coding RNAs that play critical roles in regulating gene expression at the post-transcription level. PackGene’s miRNA lentiviral vectors are engineered to overexpress or inhibit the activity of specific miRNAs. They enable the study of miRNA function in various biological processes and diseases, offering insights into miRNA-mediated regulation of gene expression. These vectors are valuable for both basic research and in the development of miRNA-based therapeutic strategies. Manipulation of miRNA function may be especially revealing in areas like cancer, where miRNAs are known to play pivotal roles in disease progression and the response to treatment.
To design a miRNA LVV transfer plasmid, we recommend a H1 or U6 promoter followed by your miRNA sequence, then include a strong promoter and a selection marker as needed.
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What are the differences between in vitro grade and in vivo grade lentivirus?
How much plasmid do I need to provide for lentivirus packaging?
You only need to provide 1-4 µg of plasmid. We will handle the plasmid preparation necessary for lentivirus packaging. You don't need to purchase an additional plasmid prep service unless you wish to receive more plasmid from us. Please note, the timeline in our quote already includes the plasmid preparation.
What QC tests do you conduct on your lentivirus?
Lentivirus quality control (QC) encompasses various tests to ensure the integrity and safety of lentiviral vectors for research and therapeutic applications.Our release QC testing primarily focuses on post-transduction titer, which provides a true functional titer(infectious titer) to prevent overestimation.
Post-transduction qPCR involves infecting cells with lentivirus followed by quantifying viral titers using quantitative PCR (qPCR), providing essential information about lentiviral transduction efficiency.
Transduction tests are performed by infecting cells with lentivirus and diluting them to count fluorescent cells. Bright field and fluorescent microscopy images are then analyzed to evaluate transduction efficiency.
Additional QC tests include p24 ELISA to measure the core capsid protein of HIV for accurate lentivirus titration, PCR-based mycoplasma testing to ensure absence of contamination, bioburden testing to quantify live microorganisms, and endotoxin testing using the Limulus amebocyte lysate (LAL) assay to confirm absence of endotoxin contamination.
These comprehensive QC tests ensure that lentiviral vectors are of high quality, free from contaminants, and suitable for downstream research and therapeutic applications.
What are the benefits of using the 3rd generation lentivirus system?
How should lentivirus be stored, and what is their shelf life?
What is the genome capacity between the 5' LTR and 3' LTR of lentivirus?
How is the lentivirus titer determined?
We employ a different approach. Our titer measurement focuses on the post-transduction titer determined by qPCR, which helps to eliminate any concerns regarding overestimation, providing infectious titers that are significantly higher (100-1000 times) than the physical titer measured by p24, ensuring greater accuracy and consistency for experimental applications.
Additionally, if the lentivirus carries a fluorescent protein, we can further validate the post-transduction titer by examining bright-field and fluorescent microscopy images obtained from serial dilutions of the virus.
What is the difference between physical titer and infectious titer?
Do you offer assistance design lentivirus plasmid?
Yes. We offer piVector Designer, an online-tool to help you design the lentivirus plasmid. The plamid backbones of various application we provided in piVector Designer is experimentally validated by us, and we provide a vast library of gene elements including promoter, reporter/marker, regulatory elements and polyA. Also, our Ph.D. level techincal support team will evaluate
