Type I interferon as a link between innate and adaptive immunity through dendritic cell stimulation.

Type I interferon (IFN-alpha/beta) is expressed rapidly after infection and plays a key role in innate defense against pathogens. Recent studies have shown that a connection exists between IFN-alpha/beta and antigen-presenting dendritic cells (DCs) at two levels. Firstly, a specific DC precursor, the plasmacytoid pre-DC (p-preDC), was identified as a cell type able to secrete very high amounts of IFN-alpha/beta following stimulation with infectious agents. Secondly, IFN-alpha/beta has been shown to act as a differentiation/maturation factor for DCs. These findings will be discussed in association with evidence indicating that IFN-alpha/beta can enhance and modulate immune responses in vivo. Taken together, the available data suggest that IFN-alpha/beta serves as a link between the innate response to infection and the adaptive immune response.