Figure 5.

Neutralization of endosomal acidification enhanced MHCI presentation of F-HIV but had no effect for C-HIV. (A–D) IDCs and MDCs were preincubated with mock or NH₄Cl (60 mM). The different groups of DCs were incubated overnight, washed, and cocultured with (A, B) an HIV-1 gag p17 SL9 (SLYNTVATL) specific CD8⁺ T-cell clone or (C and D) an HIV-1 p24 LI13 (LNKIVRMYSPTS) specific CD4⁺ T-cell clone. T-cell responses were assessed by IFN-γ ELISPOT assay. (E and F) IDCs were exposed to F-HIV or C-HIV and cultured for 2, 6, and 24 h and then stained with a lysosensor that becomes more fluorescent in acidic environments (green), p24 antibody (red), and DAPI (cell nuclei, blue). (E) The colocalization between p24 and acidic compartments was assessed and (F) representative cells are shown. Scale bar, 10 μm. Each symbol represents an individual sample/replicate and data are shown as mean +SEM of 2–12 samples from four independent experiments performed. *p<0.05, **p<0.005, ***p<0.0001, two-sided paired t-test.