Fig. 4

Transfer of fluorescent Envelope from donor to target cells through cell-to-cell spread. a Jurkat cells co-transfected with Env-isfGFP-∆V1V2 and NL4-3 were used as donor cells and primary CD4 T cells were used as target cells. Gates indicate the portion of target cell transferred with Env after co-culture. b and c Co-cultured cells were attached onto poly-lysine treated cover glass, fixed and observed under fluorescent confocal microscope. Bar = 5 μm. d Jurkat cell co-transfected with Env-isfGFP-∆V1V2 and Gag-iCherry were used as donor cells. Gates indicate the percentage of target cells carrying transferred Gag or Env after co-culture. Control condition examines donor and target cells maintained in separate wells and fixed before flow cytometry, Leu3a condition tests the inhibitory potential of Env-blocking anti-CD4 antibody Leu3a