FIG. 4.

Generation of persistently infected NT2 cells. NT2 cells were infected with rMVHcRed-CAMH at an MOI of 0.1. (A) Syncytium formation was apparent after 24 h. (B) After further cultivation, most of the cells died (4 days postinfection [d.p.i.]). (C) A small percentage of the cells survive and are persistently infected (7 d.p.i.). (D) These persistently infected cells can be grown and passaged but do not form syncytia (21 d.p.i.). The expression of HcRed (E) by piNT2-HcRed cells was compared with the expression of the viral N protein (F) after staining with MAb F227 and secondary antibodies by flow cytometry. Persistently infected NT2 cells were transduced with shM (G, H)- and shL (I, J)-producing lentiviral particles and incubated for 12 days. The phase-contrast pictures and fluorescence overlays with red (infection) and green (lentiviral vectors) are shown, respectively. The arrow in J points to a yellow cell (transduced and still infected).