HIV-1 Capture and Antigen Presentation by Dendritic Cells: Enhanced Viral Capture Does Not Correlate with Better T Cell Activation

During HIV-1 infection, dendritic cells (DC) facilitate dissemination of HIV-1 while trying to trigger adaptive antiviral immune responses. We examined whether increased HIV-1 capture in DC matured with LPS results in more efficient Ag presentation to HIV-1-specific CD4(+) and CD8(+) T cells. To block the DC-mediated trans-infection of HIV-1 and maximize Ag loading, we also evaluated a noninfectious integrase-deficient HIV-1 isolate, HIVNL4-3 Delta IN. We showed that higher viral capture of DC did not guarantee better Ag presentation or T cell activation. Greater HIVNL4-3 uptake by fully LPS-matured DC resulted in higher viral transmission to target cells but poorer stimulation of HIV-1-specific CD4(+) and CD8(+) T cells. Conversely, maturation of DC with LPS during, but not before, viral loading enhanced both HLA-I and HLA-II HIV-1-derived Ag presentation. In contrast, DC maturation with the clinical-grade mixture consisting of IL-1 beta, TNF-alpha, IL-6, and PGE(2) during viral uptake only stimulated HIV-1-specific CD8(+) T cells. Hence, DC maturation state, activation stimulus, and time lag between DC maturation and Ag loading impact HIV-1 capture and virus Ag presentation. Our results demonstrate a dissociation between the capacity to capture HIV-1 and to present viral Ags. Integrase-deficient HIVNL4-3 Delta IN was also efficiently captured and presented by DC through the HLA-I and HLA-II pathways but in the absence of viral dissemination. HIVNL4-3 Delta IN seems to be an attractive candidate to be explored. These results provide new insights into DC biology and have implications in the optimization of DC-based immunotherapy against HIV-1 infection. The Journal of Immunology, 2012, 188: 6036-6045.