Dendritic cell responsiveness to stimulation with influenza vaccine is unimpaired in old age

We have previously demonstrated that whole virus influenza vaccine can activate dendritic cells (DC). In the present study we analyzed whether DC activation was affected by the aging process. For this reason the expression of immunoregulatory molecules and the production of cytokines were compared in blood-derived DC from old and young healthy individuals following stimulation with inactivated influenza virus. Unstimulated DC from young and old individuals had a similar surface expression of MHC class II and CD54 and secreted moderate amounts of IL-12 and TNF-alpha. Stimulation with influenza vaccine led to a marked increase in the production of surface molecules and cytokines. These changes were equally pronounced in cells from young and old individuals. Our results demonstrate that DC responsiveness to stimulation with a viral vaccine is unimpaired in old age. DC may, therefore, represent a potent tool for immunotherapy and may increase the efficacy of vaccines in the elderly.