PMC

Enhanced cross-reactive cellular immune responses with intramuscular electroporation. After three immunizations, the total T-cell immune response in pEY2E1-B immunized macaques against four peptide pools of the HIV-1 group M peptides were determined by IFNγ ELISpot. The data are shown as stacked group means ± SEM.

Enhanced memory responses to HIV-1 immunogens with IM electroporation and plasmid IL-12. Five months after the last immunization, ELISpot assays were performed to determine antigen-specific memory responses to gag and env in the IM and EP immunized groups with and without co-immunization with the IL-12 plasmid. The data are shown as group mean responses ± SEM.

Induction of p24 and gp160 antibodies. Serum was collected every two weeks over the course of the study. For each time point, gag and env antibody titers were determined by p24 and gp160 ELISA, respectively, in the IM and EP immunized groups with and without co-immunization with the IL-12 plasmid. The data are shown as group mean responses ± SEM.

Enhanced cellular immune responses to HIV-1 consensus immunogens with IM co-injection of plasmid encoded IL-12 followed by EP. IFNγ ELISpots were performed two weeks after the (a) first immunization, (b) second immunization, and (c) third immunization (as seen in comparison to the other three). Responses to env are depicted as black bars and gag are depicted as white bars with the data shown as stacked group mean responses ± SEM.

CD4⁺ and CD8⁺ T cell proliferation. Cryo-preserved samples collected two weeks following the final immunization were stimulated with gag peptides and p24 protein in vitro for 5 days to determine the proliferative capacity of gag-specific T cells. Representative dot plots are shown for each group. Proliferative responses are shown as group mean responses ± SEM with CD4 depicted as white bars and CD8 are depicted as black bars.

Induction of gag-specific polyfunctional CD8⁺ T cells. PBMCs were stimulated in vitro with a gag peptide pool mix for 5 hours. Cells were then stained for intracellular production of IFNγ, TNFα and IL-2. Animals with detectable gag-specific IFNγ⁺ CD8⁺ T cells (a) were further analyzed for polyfunctional populations (b-d). Pie charts show the proportion of gag-specific CD8⁺ T cells that have 3 functions (red), 2 functions (green) or 1 function (blue). Cells incubated with complete media alone were used to determine background responses for each polyfunctional population and was subtracted from the gag-specific response. The threshold for detection was set at 10 events or 0.05%.