Specialized cells of the hematopoietic system that have branch-like extensions. They are found throughout the lymphatic system, and in non-lymphoid tissues such as skin and the epithelia of the intestinal, respiratory, and reproductive tracts. They trap and process antigens, and present them to T-CELLS, thereby stimulating CELL-MEDIATED immunity. They are different from the non-hematopoietic FOLLICULAR dendritic cells, which have a similar morphology and immune system function, but with respect to humoral immunity (ANTIBODY PRODUCTION).