Cells within the DC lineage of white blood cells are the sentinels of the immune system, the most potent of APCs; at various ports of entry, they specialize in capturing antigens and stimulating T cell–associated immunity (1–3). DCs regulate the activation of T cells not only by efficiently processing and presenting immunogenic peptides in association with self-MHC (1–4), but also via expression of coreceptor molecules such as CD80 and CD86 (5–7) and the production of cytokines such as IL-12 (8–11).
Although a role for DCs in the activation of T cells is well established, it is less clear to what extent DCs regulate other cells. It is known that DCs are essential for the development of antibody responses (12–15), but this has been thought to be simply a secondary...
