why HEK293 or HEK293T is used to produce retrovirus? - retrovirus problem! (Mar/01/2006 )

hello everyone,
would anyone tell me why HEK293 or HEK293T is the first choice ( i am not sure it's the only choice) when the retrovirus is needed. Usually, 3 vectors encoding viral Gag, Pol and Env is introdued into 293 or 293T by transient transfection. and about 2- 3 days later, the supernatant will be collected and filted as the retrovirus stock. does any special role 293 or 293T play in retrovirus production? could they be replaced by any other cell lines?
thanks a million for your answer.

I'm working on HIV (which is a retrovirus) and am indeed using HEK293T for production of HIV.

Why we're using these cells is that they are very easy to transfect and transfection efficiency is very high. Another advantage in the case of HIV (maybe not all retroviruses) is that HEK293 lacks the receptors for the virus, so once the virus is produced, it will not infect other cells, so you're not losing it. Also, the cells are capable of producing a lot without dying.

I've tried producting HIV (recombinant) by transfecting severall other cells (MT-4, Hela with CD4, and some others) and not one cell line is capable of the same amount of production that HEK293 is.

Varius, thank you very much for your information.
by the way, i have a few other questions. will 293T be lysed after production of too many retrovirus? have you ever noticed any morphology change when 293t or 293 was transfected with retroviral vectors? do you know there's any difference between 293t, 293 and 293a in terms of transfection efficiency? if 293a could be used to produce retrovirus?
i really appreciate your assistance.

I haven't worked with 293a, only with 293T. When I do my transfection on tuesday, I can harvest my virus at friday, so that's about three days of virus production and I haven't seen any signs of lysis in my cells, but on friday they are 100% confluent for a more than a day, so that's not too healthy either...
As I do my transfections with the calcium-phosphate method, the morphology of the cells changes, even though the cells survive it, it's still a stressfull situation having DNA and CaPO4 in high concentration in the medium (and even with PBS-washes you can't remove all the precipitated Calcium).

I don't know the difference between 293(T) and 293a, so you might try to find out what the difference between these two is, but I assume you can produce retrovirus using 293a.

I am producing retrovirus using Pho Amp cells which I believe they are derived from 293 cells but in this case it is an amphotrophic virus which am producing. I understand that this charactersitic is viven by the envelope protein that the packaging cell line produces as, in my case, th retroviral vector that I transfect does not contain neithe gag, pol or env.
Correct me if am wrong.