lentiviral transduction of suspension cell - (Jun/04/2007 )

I produced some lentivirus and used that to transduce differentiated U937
cells (which is adherent). I works fine.
However when I tried to transduced undifferentiated U937(which is suspension
cell). It does not work.
First time, I just add the virus to the cell in suspension.
Then I tried the spin infection
protocal. Spin the virus together with the cell at 1800rpm for 2hrs in 10 ml
ficol tube. But it still does not work.
Every time I can see green virus like particle (because my target gene is GFP
tagged ) . Mixing directly, I can see the green VLP in the medium. Using
spin infection, I can see the green VLP attaching on the cell. But the gene
is not expressed! and I think the cells are not infected .


Help, please , thank you!

Virus is invisible, what you saw was cell debris. If virus titer is too low, you may not see the weak GFP signal.