Macrophage mediated tumor cell destruction measured by an alkaline phosphatase assay

A new assay to measure the cytotoxic or growth-inhibitory activity of macrophages against tumor cells is described. The method is based on the fact that, in contrast to macrophages, natural killer cells or cytotoxic lymphocytes, a variety of tumor cells have a very high content of alkaline phosphatase. The strong linearity between tumor cell number and alkaline phosphatase activity in the cultures permits evaluation of macrophage function with standard ELISA equipment.