FIG. 1.

The R71T variation in Nef does not alter its ability to modulate cell surface expression of various human receptor molecules. HeLa-CIITA cells (27) and Jurkat cells were transfected with a bicistronic vector coexpressing GFP and the R71 (R) or T71 (T) forms of the NL4-3, 012wm-93(1), BT-94(1) 167rw-95(1), 001gh-93(1), and 057dr-94(1) Nef proteins. Values were determined as described previously (4, 23) and represent severalfold (X-fold) down-modulation of CD4, CD28, MHC-I, and MHC-II or up-regulation of Ii on cells expressing high levels of GFP and hence Nef. Shown are average values ± standard deviations derived from one representative transfection with the five pairs of R71- and T71-Nefs. Similar results were obtained in an independent experiment.