One of the main types of antigen-presenting cell in the immune system, responsible for presenting antigen to naive T cells and inducing them to become effective components of the adaptive immune response. Derived from precursors in bone marrow, dendritic cells initially are present in tissues, where they have a highly branched (i.e. dendritic) or spiky appearance. If infection arises they ingest antigen, become activated, and migrate to local lymphoid tissue. Here they activate T cells by expressing the processed antigen on their surface, in association with MHC class I and MHC class II proteins, as well as producing various co-stimulatory chemical signals. This combination of signals causes naive T cells to transiently bind to the dendritic cell and stimulates them to proliferate and differentiate into effector T cells that recognize and respond to the specific antigen presented by the dendritic cell.