In my previous lab, it was a pain transfecting THP1 cells. I think eventually we opted to purchase an electroporator (70% efficient) and that worked relatively well for our experiments. Some companies sell transfection reagents specifically for these types of cells, but we saw barely any difference using them (~30% efficient). I would opt for an electroporator if your institute has one, if not, it may be a good investment for your lab if you think you'll go into primary cells eventually. Good luck!

Hello Gabriela,

THP-1 easily get infected with HIV. Why you want to transfect them with HIV molecular clone? At any rate, we get very good transfection efficiencies using Neon transfection system (Invitrogen, now Thermo Fisher Scientific). 

That's the system we used! The Neon.

Thanks dos your help! I know many colleagues easily infects them but it doesn't work in our hands. We tried differenciated and non differenciated cells and vsv-g peusodotyped virus. Nothing worked. Do you have any extra tip? I think it might be a problem with our seed. Thanks again!

We had the same issue, productive infection was...not so productive. I think it taught me that HIV-1 is terrible at infecting cells. But how do you isolate your virus? we used to use sucrose cushions and then discovered that it de-envelopes the virus...now we just filter culture supernatants of cells expressing HIV-1 and then do a p24 ELISA for viral titre.

We just use clarified supernatants from 293T cells. We use a GFP virus and measure % of infection by flow cytometry. We barely got 5% at best....

Hello Gabriela,

In my experience, virus produced from 293T cells is not as good at infecting the THP-1 monocytes as the virus obtained from PBMCs or CEMx174. At any rate, infection of cells can always be enhanced by using high MOI and reagents such as polybrene. Hopefully you are using M- or dual-tropic HIV strains to infect the THP-1 cells.