Plasmacytoid Dendritic Cells Act as the Most Competent Cell Type in Linking Antiviral Innate and Adaptive Immune Responses

Appropriate in vivo control of plasmacytoid dendritic cell (pDC) recruitment and activation is a fundamentalrequirement for defense against viral infection.During this process,a pivotal event that influences the outcome ofviral infection is the production of high levels of type I interferon by pDCs.In particular,recent research findingsshowed that pDCs not only shape the nature of innate resistance,but are also responsible for the successfultransition from innate to adaptive immunity for viral resistance.In addition,pDCs can differentiate into antigenpresenting cells that may regulate tolerance to a given pathogen.Importantly,in a series of recent clinical studies,pDCs appeared to be defective in number and function in conditions of chronic viral diseases such as infected withHIV-1,HBV or HCV.pDC-associated clinical antiviral therapy is also emerging.This review describes researchfindings examining the functional and antiviral properties of in vivo pDC plasticity.Cellular & MolecularImmunology.2005;2(6):411-417.