iPsiRNA transfection alters DC peptide antigen presentation. TNF-α secretion by a CTL clone specific for an RU1-derived peptide epitope generated exclusively by the cP and not the iP and presented in the context of HLA-B51 was assessed. B51⁺ DCs were used as targets as either iDCs or mDCs. Maturation was induced using a CC (TNF-α, IL-6, IL-1β, and PGE₂) for 48 hours after electroporation of the DCs with siRNAs targeting the iP subunits (iPsiRNA) or control siRNA (CsiRNA). Tissue-culture supernatants were harvested 16 hours after the addition of the CTL clone (+Clone) and TNF-α concentration was determined by ELISA and expressed as mean OD₄₅₀ (± SEM). The results are representative of 3 independent experiments, each with similar results.