Current status of the host-mediated L5178Y system for detecting chemical mutagens.

Many chemicals which have been demonstrated to be mutagenic in a variety of organisms are either present in our environment or are used for human consumption. A variety of techniques have been developed for the detection of chemical mutagens. Some of these techniques have recently been reviewed and compiled (1). The important question, from the viewpoint of using these testing systems as a guide to human responsiveness, is one concerning the relevance of the results obtained from such tests to the actual or potential mutagenic hazard to man. We know too little to provide simple answers to the question, but a screening system utilizing the metabolism of potential mutagens or carcinogens by intact animals appears to be the most direct means of obtaining results that are as relevant as possible to man. Fischer first developed a cell culture system for detection of mutagens using mouse leukemic L5178Y cells; this system was later combined with the metabolic capability of the animal host in the development of a host-mediated assay system in 1969 (2). This system seems to be very useful for detecting potential mutagens in man since it detects mutagenic effects of compounds in mammalian cells. These compounds are