When a dendritic cell phagocytizes a microbe and processes it, the dendritic cell presents fragments of the microbe, called antigens, on its cell surface using a molecule called major histocompatibility complex (MHC). The dendritic cell then migrates to nearby lymph nodes, where it interacts with T cells and B cells to initiate an immune response against the microbe. The presentation of antigens by dendritic cells is a crucial step in the activation of the adaptive immune response. T cells recognize and respond to the presented antigens by proliferating and differentiating into effector T cells, which can directly kill infected cells or secrete cytokines to activate other immune cells. B cells can also interact with dendritic cells to produce antibodies against the presented antigens, which can neutralize or eliminate the microbe. In summary, when a dendritic cell phagocytizes and processes a microbe, it plays a critical role in initiating and coordinating the immune response against the microbe.