In an attempt to enhance the immunological efficacy of DNA-based vaccines, we have investigated a new biological means for delivering target gene DNA directly to professional antigen presenting cells (APC), such as the dendritic cells (DC), which are ultimately responsible for the antigen presentation and the primary activation of the immune system. For this purpose we investigated influenza virosomes (IRIV) with assembled DNA as a possible biological carrier for targeting the APC in vivo and in vitro. By cytofluorimetric analysis of the draining lymph nodes of Balb/c mice which had received (by intranasal (in.) administration) FITC-labeled DNA assembled with IRIV, we detected a significant labeled DNA uptake in a subset of lymph node deriving cells expressing DC surface markers. Subsequent mRNA analysis of these lymph nodes showed that the trans-gene delivered by the virosomes was effectively expressed as mRNA. Finally, a further cytofluorimetric analysis performed on human DC-enriched-PMBC, infected in vitro with labeled DNA/IRIV lead to the conclusion that the majority of APC (DC, B lymphocytes and CD16+ cells) are able to incorporate the labeled DNA transported by the construct. These findings suggest that the virosome is an efficient delivery system for testing infectious, as well as anti-cancer, DNA-based vaccine research.