Fig. 5.
Nef:host cell protein interaction motifs are critical for Nef-mediated CD28 downregulation. Infected CD4+ Sup-T1 cells were stained for CD28 and analyzed by flow cytometry. Cells infected with VSV-G pseudotyped NL4.3 lacking Vpu (dVpu, orange) or Vpu and Nef (dVpu dNef, green) were used as controls. a Representative dot plots illustrating CD28 (APC) and infection (GFP) in live (Zombie RedTM−) cells. b Mean (± SE) relative cell surface CD28 MFIs of cells infected with NL4.3 lacking Vpu and encoding the indicated mutations in nef (n ≥ 4). c Relative mean (± SE) total CD28 within live cells infected with NL4.3 encoding various Nef mutations (n ≥ 5). d Western blot illustrating expression of the mutated Nef proteins. (Mr: molecular weight; UI: uninfected; SE: standard error; MFI: geometric mean fluorescent intensity; *p ≤ 0.05; ***p ≤ 0.001; ****p ≤ 0.0001)