Journal of Leukocyte Biology 37:475-479 (1985) SHORT COMMUMCATION The Strain of Mouse and Assay Conditions Influence Whether MuIFN- y Primes or Activates Macrophages for Tumor

Investigators from two difterent laboratories have compared several variables in the short-term macrophage-mediated cytotoxicity assays used by each group to study the role of MuIFN- y in macrophage activation. The findings suggest that the capacity of MuIFN- y to activate macrophages without the need for a second triggering stimulus is related to assay conditions and, most especially, the strain of mouse used to provide the macrophages. Key words: macrophage activation, gamma interferon, cytolysis Macrophage activation for nonspecific tumor cell killing has now been described by investigators in many different laboratories throughout the world. The extent to which this phenomenon is being investigated indicates the potential it is thought to have with regard to host defense against neoplasia. Increasingly, the focus of research is on understanding the subcellular changes that result in activation and the expression of cytolytic activity. Unraveling the sequence of events involved, if it is to be done as rapidly as possible, will take a coordinated effort on the part of the involved scientific community. A major impediment to achieving such a coordinated effort among investigators has been the lack of a standardized assay or assays for macrophage-mediated killing. An example of the confusion that can result is apparent in the results given by two outwardly similar, but slightly different, short-term assays that have consistentl