Fig. 4.

Incorporation of Flag-tagged alkaline phosphatase in replicating HIV. (A) 293ET cells were transfected with Flag-GRB2 (FGRB2) as control and FPLAP in combination with GFP or HIV. AP activity was determined after 2 days in SN. (B and C) Supernatants from 293ET cells expressing HIV and FPLAP or GFP were collected, pre-incubated with Flag M2 antibody and magnetic beads for 2 h at 4 °C and subsequently used for infection of CEMx174-T2 (MT2) cells. After 5 days, MT2 cells infected with plain supernatant or with captured virus were analyzed by flow cytometry for percentage of MT2 cells displaying green fluorescence (B) or mean fluorescence intensity (MFI) (C). Results from three independent infections + standard deviation (SD) are shown. RLU, relative light units. ***p < 0.001; Student's t-test, paired, two-tailed.