Mononuclear phagocytes as targets for cytolytic T lymphocytes

Mouse peritoneal macrophages and human blood monocytes are excellent targets for the assay of cytolytic T lymphocytes that develop in the murine and human mixed leukocyte reactions, respectively. 51Cr release in a standard 4 h assay is equivalent to the best release that is obtained with conA-induced T lymphoblasts. Spontaneous release is consistently less than 20% of the total cell label, and syngeneic macrophages are not lysed. Unlike lymphoblasts, mononuclear phagocytes can be used either as freshly isolated cells or after prolonged periods (1-7 days) in culture.