Hi Anna, we also have problems to generate our iPS cells. We use stemcca viruses and we use the MOI 2. The efficiency is very low. now we are using plasmids to generate iPS from blood cells, and it is working better. If you want I can send you this protocol.

Good look,

Virginia

Do you make the iPS cells yourself?  Can you infect the precursor cell at high efficiency, and then make it into iPS once it already has the transgene? 

Thanks for answers, but my question is not about the reprogramming cells to the ipsc. I am doing transduction to ipsc, to express GFP in already established ipsc cells using lentivirus, and here I have a problem with transduction efficiency.

If efficiency of your lentiviral transduction is low try:

 1). Enhance concentration of viral particles.

You can use Lenti-X Concentrator (Takara).

 2). Culture hiPSC cells without MEF feeder layer

Better efficiency of lentiviral transduction you get in feeder free system. Try to grow hiPSC cells on Matrigel in MEF conditioned medium (optimize of human aktivin A level, passage hiPSC with Tryple, or accutase).

 2). Use hexadimethrine bromide (Polybrene) to enhance transduction efficiency

or

 3). Lenti-X Accelerator (Takara)

If your cells are sensitive on polybrene use Lenti-X Accelerator, which is a magnetic bead-based technology designed to accelerate lentiviral transduction experiments.

If efficiency of your transduction is still zero, this means that you have problem with promotor. In this situation you should change promotor.

Xia X, Zhang Y, Zieth CR, Zhang SC.,

Transgenes delivered by lentiviral vector are suppressed in human embryonic stem cells in a promoter-dependent manner.

Stem Cells Dev. 2007 Feb;16(1):167-76.

Protocol for Transduction of Human Embryonic Stem Cells (hESCs) using Lentiviral Vectors

http://www.sigmaaldrich.com/technical-documents/articles/biofiles/protocol-for-transduction.html