CLEC9A and viral infectious disease: This DC subtype is especially efficient at taking up and processing Ag from dead cells, and cross-presenting these Ag on major histocompatibility complex (MHC) class I. Clec9A is a receptor involved in this process, binding filamentous actin exposed when the cell membrane is damaged and facilitating the cross-presentation of dead cell-associated Ag.13,14 Mice lacking Clec9A are more susceptible to viral infections.15 Thus, targeting vaccine Ags to Clec9A plugs them into a natural and efficient Ag uptake and processing system.