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Enhanced anti-HIV-1 T cell responses stimulated by dendritic cells loaded with consensus subtype B, wild-type or autologous gag mRNA
Presented by Ellen Van Gulck, Belgium.
Van Gulck E.1, Heyndrickx L.1, Coppens S.1, Van Tendeloo V.2, Berneman Z.2, Vanham G.1
1Institute of Tropical Medicine, Microbiology, Antwerp, Belgium, 2Antwerp University Hospital, Medicine, Antwerp, Belgium
Objectives: Therapies that suppress HIV-1 replication following therapy discontinuation are very important. Dendritic cells (DC) vaccines using inactivated autologous virus have demonstrated ability to augment immunity to HIV infection. We previously shown that DC, from therapy naïve HIV-1-infected persons, electroporated with autologous gag mRNA could trigger ex vivo HIV-specific T cell responses. We hypothesize that dendritic cells from HAART treated person’s electroporated with autologous gag mRNA can also boost and broaden the HIV-specific immune response in vitro.
Methods: Monocyte derived DC from HAART treated and therapy naive subjects were electroporated with consensus subtype B (hHxB-2) gag, wild-type gag (wt-gag) or with autologous gag mRNA. These DC were coculutered for 1 week with autologous peripheral blood lymphocytes (PBL). Potential expansion of specific T cells was measured by comparing ELISPOT responses of PBL before and after co-culture, using a pool of overlapping peptides, spanning the HxB-2 Gag.
Results: DC from naïve and HAART treated HIV-1-seropositive subjects, electroporated with hHxB-2 gag mRNA could efficiently expand autologous effector memory T cells which secrete IFN-g IL-2 and perforin. The expansion after 1 week stimulation is higher in HAART treated subjects as compared to naïve subjects, matched for CD4 T cell count (n= 12). DC from HAART treated subjects electroporated with either wt-gag or autologous gag mRNA could also expand efficiently HIV-specific T cells, secreting IFN-g, IL-2 and perforin (n=9). Epitope mapping of p24 showed that PBL stimulated with gag mRNA-electroporated DC broadened the immune response: more Gag epitopes elicited IFN-g in co-cultured as compared to non-stimulated ex vivo PBL (n=6).
Conclusions: DC’s loaded with hHxB-2, wt or autologous gag mRNA are potent stimulators of virus specific T cell reactivity in vitro. Further on PBL stimulated with hHxB-2 gag electroporated DC present a broad repertoire of HIV-1 epitopes. These results support use of gag mRNA-electroporated DC as an immunotherapy in HIV-1 infection.
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