EVIDENCE THAT MACROPHAGES ARE PROGRAMMED TO DIE AFTER ACTIVATING AUTOLOGOUS, CLONED, ANTIGEN-SPECIFIC, CD4-CELLS( T)

The bone marrow produces large numbers of monocytes daily, but the mec hanisms balancing production and elimination are unknown. In this repo rt we demonstrate that macrophages (MPHI) undergo apoptosis after acti vating autologous CD4+ cells. Since apoptosis is a genetically program med response, these results argue that MPHI death can be part of a nor mal immune response. This event may have relevance to monocyte/MPHI ho meostasis, as well as immune response regulation and host defenses to intracellular organisms.