MMLV retroviral vectors serve as efficient viral vector tools for introducing genes permanently into a wide variety of dividing cells. It particularly came into prominence as a gene delivery method for generating iPS cells. VectorBuilder has developed a series of proprietary technologies and reagents that greatly improved MMLV packaging protocols in terms of titer, purity, viability and consistency, especially for the MMLV vector systems used in our vector cloning services. As a result, we have a growing base of highly satisfied customers who come back to us time after time for their MMLV vector cloning and packaging needs.
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How do I obtain MMLV packaging services?

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Types of MMLV retrovirus offered

We offer packaging services for VSV-G pseudotyped MMLV retrovirus.

Price and turnaround

Due to our technological advantage, our MMLV packaging services have the highest quality in the industry and are also faster and more affordable than those from other suppliers. Prices and turnaround time for different scales of MMLV packaging are shown below:

サイズ 使用実験系 タイター& 容量* 価格(税抜き) 作業日数**
パイロット 培養細胞 >107 TU/ml, 10x 25 ul, HBSS buffer


7-14 日
中容量 培養細胞 >107 TU/ml, 10x 100 ul, HBSS buffer 89,000円 7-14 日
大容量 培養細胞 >108 TU/ml, 10x 100 ul, HBSS buffer 139,000円 7-14 日
超純粋大容量 培養細胞 in vivo >108 TU/ml, 10x 100 ul, HBSS buffer 201,500円 7-14 日

* Our titer guarantee only applies to vectors for which the region being packaged into virus (from 5’ MoMuLV LTR to 3’ MoMuLV LTR) is below MMLV cargo limit (8 kb). For sizes over this range, it may still be possible to package the vector into virus, but the titer may be reduced. Additionally, we are not able to guarantee titer for the following vectors:

  • vectors containing sequences that could adversely affect the packaging process such as toxic genes (e.g. proapoptotic genes), genes that compromise the integrity of packaging cells or virus (e.g. membrane proteins that cause cell aggregation), and sequences prone to rearrangements or secondary structures (e.g. repetitive or highly GC-rich sequences);
  • customer-supplied vectors as we have no control over their quality.

** Turnaround time is defined as the time from when an order is accepted to when it is shipped. It does not include waiting time for any materials that the customer needs to supply (e.g. viral vectors).


If you choose pilot, medium or large scale MMLV packaging, each order includes the following deliverables:

  • Aliquots of custom MMLV at selected scale
  • Free: aliquots of control virus*
  • Free: Polybrene (5 mg/ml, 200 ul)

If you choose ultra-purified large scale MMLV packaging (in vivo grade), each order includes the following deliverables:

  • Aliquots of custom MMLV at selected scale
  • "Add-on" purchase (optional): aliquots of ultra-purified control virus*
  • Free: Polybrene (5 mg/ml, 200 ul)
* The control virus is designed to match the biological application of the custom virus and to be used for testing transduction. For example, if the custom virus overexpresses a gene, then the control virus provided will overexpress EGFP. Detailed information of the control virus is shown below:
Vector System Control Vector Name Control Vector ID Custom Virus Packaging Scale Control Virus Amount Price (USD)
MMLV gene expression system pAV[Exp]-CMV>EGFP VB170316-1032yra Pilot >107 TU/ml, 100 ul in HBSS Free
Medium >107 TU/ml, 2x 100 ul in HBSS Free
Large >107 TU/ml, 2x 100 ul in HBSS Free
Ultra-purified large >108 TU/ml, 10x 100 ul in HBSS TBD
Production, purification and titration

For our MMLV packaging, the transfer vector carrying the gene of interest (GOI) is co-transfected with our proprietary envelop vector encoding VSV-G and packaging vector encoding Gag and Pol into packaging cells. After a short incubation period, the supernatant is collected, followed by the removal of cell debris by centrifugation, filtration and PEG concentration of the viral particles. For ultra-purified (in vivo grade) MMLV, viral particles are further purified and concentrated by sucrose cushion centrifugation. We use a qPCR-based approach to measure the functional titer of MMLV.

Quality control

For each MMLV produced by VectorBuilder, quality control includes titer measurement, sterility test for bacteria and fungi, and mycoplasma detection. If the transfer vector encodes a fluorescent protein, we would transduce cells with the virus for detection of the corresponding fluorescence. Additionally, for ultra-purified MMLV, we routinely check virus quality by endotoxin assay.

Customer-supplied vectors

If customer-supplied MMLV vectors are needed, please send us the vectors following the Materials Submission Guidelines. Please strictly follow our guidelines to set up shipment to avoid any delay or damage of materials. All customer-supplied materials undergo mandatory QC by VectorBuilder which may incur a 12,500JPY surcharge per material. Please note that production may not be initiated until customer-supplied materials are received and pass QC.


Please refer to our Vector FAQ for commonly asked technical questions. To get additional information on our offerings, please contact VectorBuilder service team following the contact information here.