Issues

Cover picture: Virus (such as herpes simplex virus) invasion triggers natural interferon (IFN) pre­dendritic cell (DC)2 or IFN-alpha/beta­producing cells (IPCs) to produce vast amounts of antiviral IFN-alpha/beta and tumor necrosis factor (TNF)-alpha. IFN-alpha/beta and TNF-alpha induce pre-DC2/IPCs to differentiate into DCs (HSV-DC2). HSV-DCs stimulate naive CD4⁺ T cells to produce interleukin (IL)-3, which may induce pre-DC2/IPCs to differentiate into DCs (IL-3­DC2). IL-3­DC2s stimulate naive CD4⁺ T cells to produce T helper cell type 2 cytokines IL-4, IL-5, and IL-10. Thus, IPCs may play two master roles in antiviral immune response: directly inhibiting viral replication by producing large amounts of IFN-alpha/beta, and subsequently triggering and dictating adaptive T cell­mediated immunity by differentiating into DCs. See related article in this issue by Kadowaki et al., pp. 219-225.