Evidence that macrophages are programmed to die after activating autologous, cloned, antigen‐specific, CD4+ T cells

Abstract
The bone marrow produces large numbers of monocytes daily, but the mechanisms balancing production and elimination are unknown. In this report we demonstrate that macrophages (Mϕ) undergo apoptosis after activating autologous CD4+ cells. Since apoptosis is a genetically programmed response, these results argue that MΦ death can be part of a normal immune response. This event may have relevance to monocyte/Mϕ homeostasis, as well as immune response regulation and host defenses to intracellular organisms.