Fig 1.

Preserved downregulation of HLA-I by modified Nef proteins in HIV-1-infected cells. CD4⁺ T1 cells were infected with the HIV-1 strains listed in Table 2, with the addition of the murine CD24 reporter gene in the vpr locus. (A) Flow cytometry was performed by gating on the reporter-expressing (infected) cells, with staining for A*02. (B) Results after gating on the infected cells are shown for the indicated viruses, comparing the mutant versions of Nef without (closed lines, filled) and those with (closed lines, unfilled) the M20A mutation, which ablates HLA-I downregulation. Isotype control staining also is shown (dotted lines, unfilled). The percentages of downregulation of HLA-A*02 by WT Nef compared to the corresponding M20A mutant version for Nef-WT, SL9i, SL9r, KF11i, and TW10i were 58% ± 9%, 61% ± 15%, 65% ± 7%, 50% ± 4%, and 62% ± 4%, respectively, based on a minimum of three independent experiments. FITC, fluorescein isothiocyanate; PE, phycoerythrin.