[Help] frustrated! the lentivirus titer is very low----- - (Sep/26/2006 )

I used the plentiTOPO system from invitrogen to produce lentivirus. The GFP control vector seemed to be good for virus production, but only <20 cells(MCF-7) could be infected. My interest virus could not be detected untill now. I think the virus titer is too low to be detected.

Who can help me adress this problem? I have worked on it for two months!!!!

Thanks a lot!

there r many things to it. U need to explain more abt how u r doing the whole virus prep. I am also using the same lenti system from invitrogen.

How do u transfect? How is ur transfection efficiency?

what r the features in ur vector? This can make a huge difference in titres.