CD8+ T cell IFN-γ ELISpot
AIDS
AIDS
All samples assessed were from week 28, 2 weeks post 3rd vaccination apart from 1 participant from the Ad26/MVA group at week 50, 2 weeks post 4th vaccination.Where sufficient cells remained after VIA setup, 7 days expanded CD8+ T cells from post 3rd vaccination were assessed for IFN-γ ELISpot responses to Gag, Pol, and Env potential T cell epitope (PTE) peptide pools obtained through the NIH HIV Reagent Program, Division of AIDS, NIAID, NIH, Germantown, USA, contributed by DAIDS/NIAID (cat. numbers 11554, 11552, and 11551, respectively). ELISpot responses were determined to peptide subpools that were grouped by sequence order within the protein. These data determined the targeting of which HIV-1 proteins may be associated with the observed CD8+ T cell-mediated inhibition of HIV-1 replication. Seven days of expanded CD8+ T cells were washed three times to remove IL-2 and rested in RPMI 1640 medium with 20% (vol/vol) fetal calf serum without IL-2 for 24 h prior to ELISpot analysis (For an ELISpot assay testing frozen, thawed, and overnight rested PBMC from clinical trial participants to be considered valid, ELISpot responses to mock stimulus must be less than 50 SFU per million PBMC and PHA responses greater than 500 SFU per million PBMC. This was also the case for bispecific antibody/IL2 expanded and then rested CD8 T cells in all participants in the present study apart from participant 0675 (mock SFU 119 per million cells). The bispecific antibody/IL2 expansion results in activation of CD8+ T cells. Washing and 24 h resting of expanded CD8+ T cells ameliorates this activation in most but not all participants.